crates/common/src/auth/permissions.rs

@@ -296,6 +296,17 @@ impl Default for DefaultPermissions {
                     default.superuser.push(permission);
                     default.tenant.push(permission);
                 }
+                // inbuxa: DLP and mail flow rules, and held mail, are the
+                // server's: never a tenant's (dlp-and-mail-flow-rules spec,
+                // settled answer 3)
+                Permission::SysMailRuleGet
+                | Permission::SysMailRuleUpdate
+                | Permission::SysDlpPolicyGet
+                | Permission::SysDlpPolicyUpdate
+                | Permission::SysDlpReviewGet
+                | Permission::SysDlpReviewUpdate => {
+                    default.superuser.push(permission);
+                }
                 // inbuxa: AL-12: tenant administrators lock and delegate
                 // within their tenant
                 Permission::SysAccountLockGet

crates/common/src/manager/compliance_roles.rs

@@ -65,6 +65,10 @@ const OFFICER: &[Permission] = &[
     Permission::SysLegalHoldUpdate,
     Permission::SysLegalHoldExport,
     Permission::SysAccountLockGet,
+    // dlp-and-mail-flow-rules spec, §2.8: see DLP rules, review held mail
+    Permission::SysDlpPolicyGet,
+    Permission::SysDlpReviewGet,
+    Permission::SysDlpReviewUpdate,
 ];
 
 /// What a tenant's officer holds besides [`READS`].
@@ -113,6 +117,11 @@ fn created_key(tenant: Option<Id>) -> ValueClass {
     })
 }
 
+/// The server-level Compliance Officer role the server made, if it has.
+pub async fn server_role(data: &Store) -> trc::Result<Option<Id>> {
+    recorded(data, None).await
+}
+
 async fn recorded(data: &Store, tenant: Option<Id>) -> trc::Result<Option<Id>> {
     Ok(data
         .get_value::<u64>(ValueKey::from(created_key(tenant)))
@@ -172,13 +181,19 @@ pub async fn ensure_compliance_roles(registry: &RegistryStore, data: &Store) ->
 
 /// A new tenant gets its Compliance Officer role.
 pub async fn tenant_created(registry: &RegistryStore, data: &Store, tenant: Id) -> trc::Result<()> {
-    create_once(registry, data, Some(tenant), tenant_role(tenant)).await.map(|_| ())
+    create_once(registry, data, Some(tenant), tenant_role(tenant))
+        .await
+        .map(|_| ())
 }
 
 /// Before a tenant is deleted: removes its Compliance Officer role if nobody
 /// holds it, so the role doesn't block the delete. Returns whether it did,
 /// so a delete refused for another reason can put it back.
-pub async fn tenant_deleting(registry: &RegistryStore, data: &Store, tenant: Id) -> trc::Result<bool> {
+pub async fn tenant_deleting(
+    registry: &RegistryStore,
+    data: &Store,
+    tenant: Id,
+) -> trc::Result<bool> {
     let Some(role) = recorded(data, Some(tenant)).await? else {
         return Ok(false);
     };
@@ -220,7 +235,9 @@ mod tests {
             // Beyond what any user holds for their own account
             for permission in all.into_iter().filter(|p| !user.contains(p)) {
                 let name = permission.as_str();
-                let holds = name.starts_with("sysLegalHold");
+                // Placing holds and reviewing held mail are the officer's
+                // job, not settings (settled answers 2 and 4)
+                let holds = name.starts_with("sysLegalHold") || name.starts_with("sysDlpReview");
                 assert!(
                     !(name.ends_with("Update") && !holds)
                         && !(name.ends_with("Create") && !holds)
@@ -249,7 +266,11 @@ mod tests {
             assert!(officer.contains(&hold));
             assert!(!tenant.contains(&hold));
         }
-        for both in [Permission::SysComplianceGet, Permission::SysAuditGet, Permission::SysAccountGet] {
+        for both in [
+            Permission::SysComplianceGet,
+            Permission::SysAuditGet,
+            Permission::SysAccountGet,
+        ] {
             assert!(officer.contains(&both) && tenant.contains(&both));
         }
         assert!(!officer.contains(&Permission::SysAuditSettingsUpdate));
@@ -257,9 +278,15 @@ mod tests {
 
     #[test]
     fn records_are_per_place() {
-        let ValueClass::Any(server) = created_key(None) else { panic!() };
+        let ValueClass::Any(server) = created_key(None) else {
-        let ValueClass::Any(a) = created_key(Some(Id::from(1u64))) else { panic!() };
+            panic!()
-        let ValueClass::Any(b) = created_key(Some(Id::from(2u64))) else { panic!() };
+        };
+        let ValueClass::Any(a) = created_key(Some(Id::from(1u64))) else {
+            panic!()
+        };
+        let ValueClass::Any(b) = created_key(Some(Id::from(2u64))) else {
+            panic!()
+        };
         assert_eq!(server.key, b"Pc");
         assert_ne!(a.key, b.key);
         assert!(a.key.starts_with(b"Pc"));

crates/common/src/manager/granted_permissions.rs

@@ -46,6 +46,21 @@ const ADMIN_GRANTS: &[Permission] = &[
     Permission::SysLegalHoldUpdate,
     Permission::SysLegalHoldExport,
     Permission::SysComplianceGet,
+    Permission::SysMailRuleGet,
+    Permission::SysMailRuleUpdate,
+    Permission::SysDlpPolicyGet,
+    Permission::SysDlpPolicyUpdate,
+    Permission::SysDlpReviewGet,
+    Permission::SysDlpReviewUpdate,
+];
+
+/// Granted to the server-level Compliance Officer role once it exists:
+/// seeing DLP rules and reviewing held mail (dlp-and-mail-flow-rules spec,
+/// §2.8, settled answer 4). A new install's role has them from the start.
+const OFFICER_GRANTS: &[Permission] = &[
+    Permission::SysDlpPolicyGet,
+    Permission::SysDlpReviewGet,
+    Permission::SysDlpReviewUpdate,
 ];
 
 /// Granted to the default tenant administrator roles: reading and exporting
@@ -65,13 +80,16 @@ const TENANT_GRANTS: &[Permission] = &[
 enum Audience {
     Admin,
     Tenant,
+    Officer,
 }
 
 fn granted_key(permission: Permission, audience: Audience) -> ValueClass {
     let mut key = b"Pg".to_vec();
     // Admin grants keep the key they were first recorded under
-    if audience == Audience::Tenant {
+    match audience {
-        key.extend_from_slice(b"tenant:");
+        Audience::Admin => {}
+        Audience::Tenant => key.extend_from_slice(b"tenant:"),
+        Audience::Officer => key.extend_from_slice(b"officer:"),
     }
     key.extend_from_slice(permission.as_str().as_bytes());
     ValueClass::Any(AnyClass {
@@ -82,7 +100,8 @@ fn granted_key(permission: Permission, audience: Audience) -> ValueClass {
 
 pub(crate) async fn grant_new_admin_permissions(bp: &mut Bootstrap) -> trc::Result<()> {
     grant(bp, Audience::Admin, ADMIN_GRANTS).await?;
-    grant(bp, Audience::Tenant, TENANT_GRANTS).await
+    grant(bp, Audience::Tenant, TENANT_GRANTS).await?;
+    grant(bp, Audience::Officer, OFFICER_GRANTS).await
 }
 
 async fn grant(bp: &mut Bootstrap, audience: Audience, grants: &[Permission]) -> trc::Result<()> {
@@ -101,39 +120,47 @@ async fn grant(bp: &mut Bootstrap, audience: Audience, grants: &[Permission]) ->
     if pending.is_empty() {
         return Ok(());
     }
-    // An administrator's default roles include the plain User role, which
+    // The officer role is the one the server made, if it has made it yet: a
-    // every user also holds; only roles that are the audience's alone get it
+    // new install makes it after this, with the permissions already in it
-    let admin_roles: Vec<Id> = bp
+    let admin_roles: Vec<Id> = if audience == Audience::Officer {
-        .registry
+        super::compliance_roles::server_role(&bp.data_store)
-        .object::<Authentication>(Id::singleton())
+            .await?
-        .await?
+            .into_iter()
-        .map(|auth| {
+            .collect()
-            let (own, shared) = match audience {
+    } else {
-                Audience::Admin => (
+        // An administrator's default roles include the plain User role, which
-                    auth.default_admin_role_ids.as_slice(),
+        // every user also holds; only roles that are the audience's alone get it
-                    [
+        bp.registry
-                        auth.default_user_role_ids.as_slice(),
+            .object::<Authentication>(Id::singleton())
-                        auth.default_group_role_ids.as_slice(),
+            .await?
-                        auth.default_tenant_role_ids.as_slice(),
+            .map(|auth| {
-                    ]
+                let (own, shared) = match audience {
-                    .concat(),
+                    Audience::Admin => (
-                ),
-                Audience::Tenant => (
-                    auth.default_tenant_role_ids.as_slice(),
-                    [
-                        auth.default_user_role_ids.as_slice(),
-                        auth.default_group_role_ids.as_slice(),
                         auth.default_admin_role_ids.as_slice(),
-                    ]
+                        [
-                    .concat(),
+                            auth.default_user_role_ids.as_slice(),
-                ),
+                            auth.default_group_role_ids.as_slice(),
-            };
+                            auth.default_tenant_role_ids.as_slice(),
-            own.iter()
+                        ]
-                .filter(|id| !shared.contains(id))
+                        .concat(),
-                .copied()
+                    ),
-                .collect()
+                    Audience::Tenant | Audience::Officer => (
-        })
+                        auth.default_tenant_role_ids.as_slice(),
-        .unwrap_or_default();
+                        [
+                            auth.default_user_role_ids.as_slice(),
+                            auth.default_group_role_ids.as_slice(),
+                            auth.default_admin_role_ids.as_slice(),
+                        ]
+                        .concat(),
+                    ),
+                };
+                own.iter()
+                    .filter(|id| !shared.contains(id))
+                    .copied()
+                    .collect()
+            })
+            .unwrap_or_default()
+    };
     // Fetched by id: the registry's listing doesn't reach stored roles
     for role_id in admin_roles {
         let Some(stored) = bp

crates/features/src/mailflow/cache.rs

@@ -0,0 +1,53 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! The compiled rules, kept per node so a message doesn't read the store.
+//! A change made on this node applies at once; one made on another node
+//! within [`TTL`], when the copy here is next refreshed.
+
+use super::{engine::Compiled, rules};
+use std::{
+    sync::{Arc, RwLock},
+    time::{Duration, Instant},
+};
+use store::Store;
+
+/// How long a node keeps its copy before reading the rules again.
+pub const TTL: Duration = Duration::from_secs(30);
+
+static CACHE: RwLock<Option<(Instant, Arc<Compiled>)>> = RwLock::new(None);
+
+/// Forgets the copy, so the next message reads the rules again.
+pub fn invalidate() {
+    if let Ok(mut cache) = CACHE.write() {
+        *cache = None;
+    }
+}
+
+/// The enabled rules, compiled. A rule that no longer compiles is left out
+/// and reported, once per refresh.
+pub async fn compiled(data: &Store) -> trc::Result<Arc<Compiled>> {
+    if let Ok(cache) = CACHE.read()
+        && let Some((at, compiled)) = cache.as_ref()
+        && at.elapsed() < TTL
+    {
+        return Ok(compiled.clone());
+    }
+    let (compiled, skipped) = Compiled::new(&rules::all(data).await?);
+    for (id, reason) in skipped {
+        trc::event!(
+            Store(trc::StoreEvent::DataCorruption),
+            Id = u64::from(id),
+            Reason = reason,
+            Details = "Mail rule skipped: it no longer compiles"
+        );
+    }
+    let compiled = Arc::new(compiled);
+    if let Ok(mut cache) = CACHE.write() {
+        *cache = Some((Instant::now(), compiled.clone()));
+    }
+    Ok(compiled)
+}

crates/features/src/mailflow/engine.rs

@@ -0,0 +1,695 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! Evaluating rules against a message (§2.1–§2.4). Rules are compiled once,
+//! when they change: word lists become automata, patterns regexes. A message
+//! is then checked against every enabled rule in order; each detector runs
+//! at most once per message, and only when some rule asks for it.
+//!
+//! Pure: the caller parses the message, extracts attachment text
+//! ([`super::extract`]) and knows the sender's groups and tenant. What comes
+//! back is which rules matched, with each detector's count, and what DLP
+//! decided; the matched text itself never leaves here (§2.7).
+
+use super::{
+    detectors::{self, Findings},
+    extract::Extracted,
+    rules::{Action, Condition, Direction, Kind, Rule},
+    words::{Pattern, WordList},
+};
+use ahash::AHashMap;
+use std::borrow::Cow;
+
+/// Who sent a message, and to whom.
+#[derive(Debug, Clone, Default)]
+pub struct Envelope<'a> {
+    /// Outgoing (an authenticated sender) or incoming.
+    pub outgoing: bool,
+    pub sender: &'a str,
+    pub sender_groups: &'a [u32],
+    pub sender_tenant: Option<u32>,
+    pub recipients: Vec<Recipient<'a>>,
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct Recipient<'a> {
+    pub address: &'a str,
+    /// At a domain this server hosts.
+    pub local: bool,
+    pub groups: &'a [u32],
+}
+
+#[derive(Debug, Clone)]
+pub struct Attachment<'a> {
+    pub name: Option<&'a str>,
+    /// Declared type, or detected where the caller knows better.
+    pub content_type: &'a str,
+    pub size: u64,
+    pub extracted: Extracted,
+}
+
+/// What rules look at.
+#[derive(Debug, Clone, Default)]
+pub struct Content<'a> {
+    pub subject: &'a str,
+    /// Each text and HTML part, as text.
+    pub bodies: Vec<Cow<'a, str>>,
+    pub headers: Vec<(&'a str, &'a str)>,
+    pub attachments: Vec<Attachment<'a>>,
+    pub size: u64,
+    /// Text past the inspection limit wasn't read.
+    pub truncated: bool,
+}
+
+impl Content<'_> {
+    fn texts(&self) -> impl Iterator<Item = &str> {
+        std::iter::once(self.subject)
+            .chain(self.bodies.iter().map(|b| b.as_ref()))
+            .chain(self.attachments.iter().filter_map(|a| match &a.extracted {
+                Extracted::Text(text) => Some(text.as_str()),
+                _ => None,
+            }))
+    }
+
+    fn cant_be_inspected(&self) -> bool {
+        self.truncated
+            || self
+                .attachments
+                .iter()
+                .any(|a| matches!(a.extracted, Extracted::NotInspectable(_)))
+    }
+}
+
+enum Check {
+    Plain(Condition),
+    Words(WordList, u32),
+    Pattern(Pattern, u32),
+    Header {
+        name: String,
+        contains: Option<String>,
+        matches: Option<Pattern>,
+    },
+    AttachmentName(Pattern),
+}
+
+struct CompiledRule {
+    rule: Rule,
+    conditions: Vec<Check>,
+    exceptions: Vec<Check>,
+}
+
+/// The enabled rules, ready to run.
+pub struct Compiled {
+    rules: Vec<CompiledRule>,
+}
+
+/// A rule reference, for notices and the audit record.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct RuleRef {
+    pub id: u32,
+    pub name: String,
+    pub notice: String,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Match {
+    pub rule_id: u32,
+    pub name: String,
+    pub kind: Kind,
+    pub actions: Vec<Action>,
+    /// Each detector (or `words`, `pattern`) that counted, and its count.
+    pub counts: Vec<(String, usize)>,
+}
+
+#[derive(Debug, Default)]
+pub struct Outcome {
+    pub matched: Vec<Match>,
+    pub blocks: Vec<RuleRef>,
+    pub holds: Vec<(RuleRef, bool)>,
+    pub warns: Vec<RuleRef>,
+}
+
+/// What DLP decided, strictest first (§2.4).
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum Decision {
+    Pass,
+    Block(Vec<RuleRef>),
+    Hold {
+        rules: Vec<RuleRef>,
+        notify_sender: bool,
+    },
+    Warn(Vec<RuleRef>),
+}
+
+impl Outcome {
+    /// Block beats hold beats warn. An override (§2.5) answers the warnings
+    /// only: a block or hold still applies.
+    pub fn decision(&self, overridden: bool) -> Decision {
+        if !self.blocks.is_empty() {
+            Decision::Block(self.blocks.clone())
+        } else if !self.holds.is_empty() {
+            Decision::Hold {
+                rules: self.holds.iter().map(|(r, _)| r.clone()).collect(),
+                notify_sender: self.holds.iter().any(|(_, notify)| *notify),
+            }
+        } else if !self.warns.is_empty() && !overridden {
+            Decision::Warn(self.warns.clone())
+        } else {
+            Decision::Pass
+        }
+    }
+}
+
+fn compile_check(condition: &Condition) -> Result<Check, String> {
+    Ok(match condition {
+        Condition::Words { words, at_least } => Check::Words(WordList::new(words)?, *at_least),
+        Condition::Pattern { pattern, at_least } => {
+            Check::Pattern(Pattern::new(pattern)?, *at_least)
+        }
+        Condition::Header {
+            name,
+            contains,
+            matches,
+        } => Check::Header {
+            name: name.to_ascii_lowercase(),
+            contains: contains.as_ref().map(|c| c.to_lowercase()),
+            matches: matches.as_deref().map(Pattern::new).transpose()?,
+        },
+        Condition::AttachmentName { pattern } => Check::AttachmentName(Pattern::new(pattern)?),
+        other => Check::Plain(other.clone()),
+    })
+}
+
+impl Compiled {
+    /// Compiles the enabled rules; one that no longer compiles (a detector
+    /// renamed since it was saved) is skipped and named in the second list.
+    pub fn new(rules: &[Rule]) -> (Self, Vec<(u32, String)>) {
+        let mut compiled = Vec::new();
+        let mut skipped = Vec::new();
+        for rule in rules.iter().filter(|r| r.enabled) {
+            let result = rule.validate().map_err(|e| e.reason).and_then(|_| {
+                Ok(CompiledRule {
+                    rule: rule.clone(),
+                    conditions: rule
+                        .conditions
+                        .iter()
+                        .map(compile_check)
+                        .collect::<Result<_, _>>()?,
+                    exceptions: rule
+                        .exceptions
+                        .iter()
+                        .map(compile_check)
+                        .collect::<Result<_, _>>()?,
+                })
+            });
+            match result {
+                Ok(c) => compiled.push(c),
+                Err(reason) => skipped.push((rule.id, reason)),
+            }
+        }
+        compiled.sort_by_key(|c| (c.rule.priority, c.rule.id));
+        (Self { rules: compiled }, skipped)
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.rules.is_empty()
+    }
+
+    /// Whether any rule could apply to mail going this way, so a caller can
+    /// skip parsing when none can.
+    pub fn applies_to(&self, outgoing: bool) -> bool {
+        self.rules
+            .iter()
+            .any(|c| direction_matches(c.rule.direction, outgoing))
+    }
+
+    pub fn evaluate(&self, envelope: &Envelope<'_>, content: &Content<'_>) -> Outcome {
+        let mut state = State {
+            content,
+            detected: AHashMap::new(),
+        };
+        let mut outcome = Outcome::default();
+        for compiled in &self.rules {
+            let rule = &compiled.rule;
+            if !direction_matches(rule.direction, envelope.outgoing) {
+                continue;
+            }
+            let mut counts = Vec::new();
+            let all_match = compiled
+                .conditions
+                .iter()
+                .all(|check| state.check(check, envelope, &mut counts));
+            if !all_match {
+                continue;
+            }
+            let mut ignored = Vec::new();
+            if compiled
+                .exceptions
+                .iter()
+                .any(|check| state.check(check, envelope, &mut ignored))
+            {
+                continue;
+            }
+            for action in &rule.actions {
+                let reference = |notice: &str| RuleRef {
+                    id: rule.id,
+                    name: rule.name.clone(),
+                    notice: notice.to_string(),
+                };
+                match action {
+                    Action::Block { notice } => outcome.blocks.push(reference(notice)),
+                    Action::Hold {
+                        notice,
+                        notify_sender,
+                    } => outcome.holds.push((reference(notice), *notify_sender)),
+                    Action::Warn { notice } => outcome.warns.push(reference(notice)),
+                    _ => {}
+                }
+            }
+            outcome.matched.push(Match {
+                rule_id: rule.id,
+                name: rule.name.clone(),
+                kind: rule.kind,
+                actions: rule.actions.clone(),
+                counts,
+            });
+            if rule.stop_processing {
+                break;
+            }
+        }
+        outcome
+    }
+}
+
+fn direction_matches(direction: Direction, outgoing: bool) -> bool {
+    match direction {
+        Direction::Any => true,
+        Direction::Outgoing => outgoing,
+        Direction::Incoming => !outgoing,
+    }
+}
+
+fn domain_of(address: &str) -> &str {
+    address.rsplit_once('@').map_or("", |(_, d)| d)
+}
+
+fn in_list(value: &str, list: &[String]) -> bool {
+    list.iter().any(|v| v.eq_ignore_ascii_case(value))
+}
+
+struct State<'c, 'a> {
+    content: &'c Content<'a>,
+    /// Each detector's count, run once per message.
+    detected: AHashMap<&'static str, usize>,
+}
+
+impl State<'_, '_> {
+    fn detector_count(&mut self, id: &str) -> usize {
+        let Some(detector) = detectors::by_id(id) else {
+            return 0;
+        };
+        if let Some(count) = self.detected.get(detector.id) {
+            return *count;
+        }
+        let mut findings = Findings::default();
+        for text in self.content.texts() {
+            detector.find(text, &mut findings);
+        }
+        self.detected.insert(detector.id, findings.len());
+        findings.len()
+    }
+
+    fn check(
+        &mut self,
+        check: &Check,
+        envelope: &Envelope<'_>,
+        counts: &mut Vec<(String, usize)>,
+    ) -> bool {
+        let content = self.content;
+        match check {
+            Check::Words(list, at_least) => {
+                let n: usize = content.texts().map(|t| list.count(t)).sum();
+                counts.push(("words".into(), n));
+                n >= *at_least as usize
+            }
+            Check::Pattern(pattern, at_least) => {
+                let n: usize = content.texts().map(|t| pattern.count(t)).sum();
+                counts.push(("pattern".into(), n));
+                n >= *at_least as usize
+            }
+            Check::Header {
+                name,
+                contains,
+                matches,
+            } => content
+                .headers
+                .iter()
+                .filter(|(n, _)| n.eq_ignore_ascii_case(name))
+                .any(|(_, value)| match (contains, matches) {
+                    (Some(needle), _) => value.to_lowercase().contains(needle.as_str()),
+                    (_, Some(pattern)) => pattern.count(value) > 0,
+                    _ => true,
+                }),
+            Check::AttachmentName(pattern) => content
+                .attachments
+                .iter()
+                .any(|a| a.name.is_some_and(|n| pattern.count(n) > 0)),
+            Check::Plain(condition) => match condition {
+                Condition::SenderAddress { addresses } => in_list(envelope.sender, addresses),
+                Condition::SenderDomain { domains } => in_list(domain_of(envelope.sender), domains),
+                Condition::SenderGroup { groups } => {
+                    envelope.sender_groups.iter().any(|g| groups.contains(g))
+                }
+                Condition::SenderTenant { tenants } => {
+                    envelope.sender_tenant.is_some_and(|t| tenants.contains(&t))
+                }
+                Condition::RecipientAddress { addresses } => envelope
+                    .recipients
+                    .iter()
+                    .any(|r| in_list(r.address, addresses)),
+                Condition::RecipientDomain { domains } => envelope
+                    .recipients
+                    .iter()
+                    .any(|r| in_list(domain_of(r.address), domains)),
+                Condition::RecipientGroup { groups } => envelope
+                    .recipients
+                    .iter()
+                    .any(|r| r.groups.iter().any(|g| groups.contains(g))),
+                Condition::RecipientOutside => envelope.recipients.iter().any(|r| !r.local),
+                Condition::AttachmentType { types } => content.attachments.iter().any(|a| {
+                    let ct = a.content_type.to_ascii_lowercase();
+                    types
+                        .iter()
+                        .any(|t| ct.starts_with(&t.to_ascii_lowercase()))
+                }),
+                Condition::AttachmentExtension { extensions } => {
+                    content.attachments.iter().any(|a| {
+                        a.name
+                            .and_then(|n| n.rsplit_once('.'))
+                            .is_some_and(|(_, ext)| {
+                                extensions
+                                    .iter()
+                                    .any(|e| e.trim_start_matches('.').eq_ignore_ascii_case(ext))
+                            })
+                    })
+                }
+                Condition::AttachmentSizeOver { bytes } => {
+                    content.attachments.iter().any(|a| a.size > *bytes)
+                }
+                Condition::AttachmentCountOver { count } => {
+                    content.attachments.len() > *count as usize
+                }
+                Condition::CantBeInspected => content.cant_be_inspected(),
+                Condition::MessageSizeOver { bytes } => content.size > *bytes,
+                Condition::Detected { detectors } => {
+                    let mut any = false;
+                    for d in detectors {
+                        let n = self.detector_count(&d.id);
+                        counts.push((d.id.clone(), n));
+                        any |= n >= d.at_least as usize;
+                    }
+                    any
+                }
+                // Compiled into their own checks
+                Condition::Words { .. }
+                | Condition::Pattern { .. }
+                | Condition::Header { .. }
+                | Condition::AttachmentName { .. } => false,
+            },
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::mailflow::{
+        extract::Why,
+        rules::{DetectorMin, Position},
+    };
+
+    fn rule(id: u32, kind: Kind, conditions: Vec<Condition>, action: Action) -> Rule {
+        Rule {
+            id,
+            name: format!("rule {id}"),
+            description: String::new(),
+            kind,
+            enabled: true,
+            priority: id as i32,
+            direction: if kind == Kind::Dlp {
+                Direction::Outgoing
+            } else {
+                Direction::Any
+            },
+            conditions,
+            exceptions: vec![],
+            actions: vec![action],
+            stop_processing: false,
+            created_by: String::new(),
+            created_at: 0,
+            updated_at: 0,
+        }
+    }
+
+    fn envelope(outside: bool) -> Envelope<'static> {
+        Envelope {
+            outgoing: true,
+            sender: "[email protected]",
+            sender_groups: &[7],
+            sender_tenant: None,
+            recipients: vec![Recipient {
+                address: if outside {
+                    "[email protected]"
+                } else {
+                    "[email protected]"
+                },
+                local: !outside,
+                groups: &[],
+            }],
+        }
+    }
+
+    fn cards(n: usize) -> Content<'static> {
+        let body: String = [
+            "4242 4242 4242 4242",
+            "5555-5555-5555-4444",
+            "378282246310005",
+            "6011111111111117",
+            "3566002020360505",
+        ]
+        .iter()
+        .take(n)
+        .map(|c| format!("card {c}\n"))
+        .collect();
+        Content {
+            subject: "Numbers",
+            bodies: vec![body.into()],
+            ..Default::default()
+        }
+    }
+
+    fn five_cards_outside(action: Action) -> Rule {
+        rule(
+            1,
+            Kind::Dlp,
+            vec![
+                Condition::RecipientOutside,
+                Condition::Detected {
+                    detectors: vec![DetectorMin {
+                        id: "payment-card".into(),
+                        at_least: 5,
+                    }],
+                },
+            ],
+            action,
+        )
+    }
+
+    #[test]
+    fn detector_threshold_and_recipients() {
+        let (rules, skipped) = Compiled::new(&[five_cards_outside(Action::Hold {
+            notice: "Held".into(),
+            notify_sender: true,
+        })]);
+        assert!(skipped.is_empty());
+        let outcome = rules.evaluate(&envelope(true), &cards(5));
+        assert_eq!(
+            outcome.matched[0].counts,
+            vec![("payment-card".to_string(), 5)]
+        );
+        assert!(matches!(
+            outcome.decision(false),
+            Decision::Hold {
+                notify_sender: true,
+                ..
+            }
+        ));
+        // Four cards, or everyone inside: nothing
+        assert_eq!(
+            rules.evaluate(&envelope(true), &cards(4)).decision(false),
+            Decision::Pass
+        );
+        assert_eq!(
+            rules.evaluate(&envelope(false), &cards(5)).decision(false),
+            Decision::Pass
+        );
+    }
+
+    #[test]
+    fn strictest_wins_and_override_answers_warnings_only() {
+        let warn = five_cards_outside(Action::Warn {
+            notice: "Sure?".into(),
+        });
+        let mut block = five_cards_outside(Action::Block {
+            notice: "No".into(),
+        });
+        block.id = 2;
+        let (rules, _) = Compiled::new(&[warn.clone(), block]);
+        let outcome = rules.evaluate(&envelope(true), &cards(5));
+        assert!(matches!(outcome.decision(true), Decision::Block(_)));
+        let (rules, _) = Compiled::new(&[warn]);
+        let outcome = rules.evaluate(&envelope(true), &cards(5));
+        assert!(matches!(outcome.decision(false), Decision::Warn(ref w) if w[0].notice == "Sure?"));
+        assert_eq!(outcome.decision(true), Decision::Pass);
+    }
+
+    #[test]
+    fn exceptions_order_and_stop_processing() {
+        let disclaimer = |id| {
+            rule(
+                id,
+                Kind::Transport,
+                vec![Condition::RecipientOutside],
+                Action::AddDisclaimer {
+                    text: "t".into(),
+                    html: None,
+                    position: Position::Bottom,
+                },
+            )
+        };
+        let mut first = disclaimer(1);
+        first.stop_processing = true;
+        let (rules, _) = Compiled::new(&[disclaimer(2), first.clone()]);
+        let outcome = rules.evaluate(&envelope(true), &cards(0));
+        assert_eq!(
+            outcome
+                .matched
+                .iter()
+                .map(|m| m.rule_id)
+                .collect::<Vec<_>>(),
+            vec![1]
+        );
+
+        first.stop_processing = false;
+        first.exceptions = vec![Condition::SenderGroup { groups: vec![7] }];
+        let (rules, _) = Compiled::new(&[disclaimer(2), first]);
+        let outcome = rules.evaluate(&envelope(true), &cards(0));
+        assert_eq!(
+            outcome
+                .matched
+                .iter()
+                .map(|m| m.rule_id)
+                .collect::<Vec<_>>(),
+            vec![2]
+        );
+    }
+
+    #[test]
+    fn content_conditions() {
+        let content = Content {
+            subject: "Project Falcon",
+            bodies: vec!["see attached".into()],
+            headers: vec![("X-Class", "Internal only")],
+            attachments: vec![
+                Attachment {
+                    name: Some("plan.docx"),
+                    content_type: "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+                    size: 40_000,
+                    extracted: Extracted::Text("IBAN GB29 NWBK 6016 1331 9268 19".into()),
+                },
+                Attachment {
+                    name: Some("scan.pdf"),
+                    content_type: "application/pdf",
+                    size: 900_000,
+                    extracted: Extracted::NotInspectable(Why::Pdf),
+                },
+            ],
+            size: 1_000_000,
+            truncated: false,
+        };
+        let block = || Action::Block { notice: "n".into() };
+        let checks = [
+            (
+                Condition::Words {
+                    words: vec!["project falcon".into()],
+                    at_least: 1,
+                },
+                true,
+            ),
+            (
+                Condition::Header {
+                    name: "x-class".into(),
+                    contains: Some("internal".into()),
+                    matches: None,
+                },
+                true,
+            ),
+            (
+                Condition::AttachmentExtension {
+                    extensions: vec![".PDF".into()],
+                },
+                true,
+            ),
+            (
+                Condition::AttachmentType {
+                    types: vec!["image/".into()],
+                },
+                false,
+            ),
+            (Condition::AttachmentSizeOver { bytes: 500_000 }, true),
+            (Condition::AttachmentCountOver { count: 2 }, false),
+            (Condition::CantBeInspected, true),
+            (Condition::MessageSizeOver { bytes: 2_000_000 }, false),
+            (
+                Condition::Detected {
+                    detectors: vec![DetectorMin {
+                        id: "iban".into(),
+                        at_least: 1,
+                    }],
+                },
+                true,
+            ),
+            (
+                Condition::SenderDomain {
+                    domains: vec!["EXAMPLE.com".into()],
+                },
+                true,
+            ),
+        ];
+        for (condition, expected) in checks {
+            let (rules, skipped) =
+                Compiled::new(&[rule(1, Kind::Dlp, vec![condition.clone()], block())]);
+            assert!(skipped.is_empty(), "{condition:?}");
+            let matched = !rules.evaluate(&envelope(true), &content).matched.is_empty();
+            assert_eq!(matched, expected, "{condition:?}");
+        }
+    }
+
+    #[test]
+    fn direction_and_disabled_rules() {
+        let mut r = five_cards_outside(Action::Block { notice: "n".into() });
+        let (rules, _) = Compiled::new(std::slice::from_ref(&r));
+        assert!(rules.applies_to(true) && !rules.applies_to(false));
+        let mut incoming = envelope(true);
+        incoming.outgoing = false;
+        assert_eq!(
+            rules.evaluate(&incoming, &cards(5)).decision(false),
+            Decision::Pass
+        );
+        r.enabled = false;
+        assert!(Compiled::new(&[r]).0.is_empty());
+    }
+}

crates/features/src/mailflow/mod.rs

@@ -6,18 +6,24 @@
 
 //! Data loss prevention and mail flow rules (dlp-and-mail-flow-rules spec).
 //!
-//! Pure functions over text and attachment bytes, so everything here is
+//! Mostly pure functions over text and attachment bytes, unit-tested
-//! unit-tested without a server:
+//! without a server:
 //!
 //! - [`detectors`]: find identifiers in text (payment cards, IBANs,
 //!   national ID numbers, keys), each by its published format and check
 //!   (§2.3);
 //! - [`words`]: an organization's own word lists and patterns;
-//! - [`extract`]: the text of an attachment, or why it can't be read.
+//! - [`extract`]: the text of an attachment, or why it can't be read;
+//! - [`rules`]: what a rule is, its checks, and where rules are kept;
+//! - [`engine`]: rules compiled and run against a message;
+//! - [`cache`]: each node's compiled copy.
 //!
 //! Nothing here writes what it finds anywhere: callers get counts, and the
 //! matched text never leaves the evaluation (§2.7).
 
+pub mod cache;
 pub mod detectors;
+pub mod engine;
 pub mod extract;
+pub mod rules;
 pub mod words;

crates/features/src/mailflow/rules.rs

@@ -0,0 +1,717 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! Mail flow rules and DLP rules (dlp-and-mail-flow-rules spec, §2.2–§2.4):
+//! what a rule is, what makes one valid, and where it's kept.
+//!
+//! Kept in the fork's subspace (`store::SUBSPACE_INBUXA`), never in the
+//! registry, so an upstream schema import never touches them. Every key
+//! starts with `R`, then one byte for the kind:
+//!
+//! - `r` + rule id (u32): the rule, as JSON.
+//!
+//! Numbers are big-endian. There are few rules, so they're read whole.
+
+use super::{detectors, words};
+use serde::{Deserialize as SerdeDeserialize, Serialize as SerdeSerialize, de::DeserializeOwned};
+use store::{
+    Deserialize, IterateParams, SUBSPACE_INBUXA, Serialize, Store, ValueKey,
+    write::{AnyClass, BatchBuilder, ValueClass, assert::AssertValue},
+};
+use trc::AddContext;
+
+const FEATURE: u8 = b'R';
+const KIND_RULE: u8 = b'r';
+const CREATE_ATTEMPTS: usize = 5;
+
+/// Longest text a rule may carry (a notice, a disclaimer), in bytes.
+const MAX_TEXT: usize = 16 * 1024;
+/// Most entries in one list (words, addresses, domains).
+const MAX_LIST: usize = 5_000;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, SerdeSerialize, SerdeDeserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum Kind {
+    Dlp,
+    Transport,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, SerdeSerialize, SerdeDeserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum Direction {
+    /// Mail an authenticated sender submits, over SMTP or JMAP.
+    Outgoing,
+    /// Everything else the server accepts.
+    Incoming,
+    Any,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, SerdeSerialize, SerdeDeserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum Position {
+    Top,
+    Bottom,
+}
+
+fn one() -> u32 {
+    1
+}
+
+/// A detector and the least it must find.
+#[derive(Debug, Clone, PartialEq, Eq, SerdeSerialize, SerdeDeserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct DetectorMin {
+    pub id: String,
+    #[serde(default = "one")]
+    pub at_least: u32,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, SerdeSerialize, SerdeDeserialize)]
+#[serde(
+    tag = "type",
+    rename_all = "camelCase",
+    rename_all_fields = "camelCase"
+)]
+pub enum Condition {
+    SenderAddress {
+        addresses: Vec<String>,
+    },
+    SenderDomain {
+        domains: Vec<String>,
+    },
+    SenderGroup {
+        groups: Vec<u32>,
+    },
+    SenderTenant {
+        tenants: Vec<u32>,
+    },
+    /// Any recipient is one of these.
+    RecipientAddress {
+        addresses: Vec<String>,
+    },
+    RecipientDomain {
+        domains: Vec<String>,
+    },
+    RecipientGroup {
+        groups: Vec<u32>,
+    },
+    /// Any recipient isn't at a domain this server hosts.
+    RecipientOutside,
+    /// Words or phrases in the subject, body or readable attachments.
+    Words {
+        words: Vec<String>,
+        #[serde(default = "one")]
+        at_least: u32,
+    },
+    /// The organization's regular expression, in the same places.
+    Pattern {
+        pattern: String,
+        #[serde(default = "one")]
+        at_least: u32,
+    },
+    /// A header exists, or its value contains or matches.
+    Header {
+        name: String,
+        #[serde(default)]
+        contains: Option<String>,
+        #[serde(default)]
+        matches: Option<String>,
+    },
+    /// An attachment's declared or detected type starts with one of these.
+    AttachmentType {
+        types: Vec<String>,
+    },
+    AttachmentExtension {
+        extensions: Vec<String>,
+    },
+    AttachmentName {
+        pattern: String,
+    },
+    AttachmentSizeOver {
+        bytes: u64,
+    },
+    AttachmentCountOver {
+        count: u32,
+    },
+    /// An attachment is encrypted, a PDF, a legacy Office file, an archive
+    /// inside an archive, or past the inspection limit.
+    CantBeInspected,
+    MessageSizeOver {
+        bytes: u64,
+    },
+    /// Any of these detectors finds at least its minimum (DLP rules only).
+    Detected {
+        detectors: Vec<DetectorMin>,
+    },
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, SerdeSerialize, SerdeDeserialize)]
+#[serde(
+    tag = "type",
+    rename_all = "camelCase",
+    rename_all_fields = "camelCase"
+)]
+pub enum Action {
+    // Transport actions
+    AddDisclaimer {
+        text: String,
+        #[serde(default)]
+        html: Option<String>,
+        position: Position,
+    },
+    AddHeader {
+        name: String,
+        value: String,
+    },
+    RemoveHeader {
+        name: String,
+    },
+    PrefixSubject {
+        text: String,
+    },
+    AddRecipient {
+        address: String,
+    },
+    Redirect {
+        addresses: Vec<String>,
+    },
+    Refuse {
+        text: String,
+    },
+    Route {
+        queue: String,
+    },
+    // DLP actions
+    Block {
+        notice: String,
+    },
+    Warn {
+        notice: String,
+    },
+    Hold {
+        notice: String,
+        #[serde(default)]
+        notify_sender: bool,
+    },
+}
+
+impl Action {
+    pub fn is_dlp(&self) -> bool {
+        matches!(
+            self,
+            Action::Block { .. } | Action::Warn { .. } | Action::Hold { .. }
+        )
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, SerdeSerialize, SerdeDeserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct Rule {
+    #[serde(default)]
+    pub id: u32,
+    pub name: String,
+    #[serde(default)]
+    pub description: String,
+    pub kind: Kind,
+    #[serde(default = "enabled")]
+    pub enabled: bool,
+    #[serde(default)]
+    pub priority: i32,
+    pub direction: Direction,
+    #[serde(default)]
+    pub conditions: Vec<Condition>,
+    #[serde(default)]
+    pub exceptions: Vec<Condition>,
+    pub actions: Vec<Action>,
+    #[serde(default)]
+    pub stop_processing: bool,
+    #[serde(default)]
+    pub created_by: String,
+    #[serde(default)]
+    pub created_at: u64,
+    #[serde(default)]
+    pub updated_at: u64,
+}
+
+fn enabled() -> bool {
+    true
+}
+
+/// Why a rule can't be saved: the property at fault, and a sentence.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Invalid {
+    pub property: &'static str,
+    pub reason: String,
+}
+
+fn invalid(property: &'static str, reason: impl Into<String>) -> Invalid {
+    Invalid {
+        property,
+        reason: reason.into(),
+    }
+}
+
+impl Rule {
+    /// Everything that can be checked without the rest of the server: the
+    /// shape (§2.2, §2.4), the detectors, word lists and patterns.
+    pub fn validate(&self) -> Result<(), Invalid> {
+        if self.name.trim().is_empty() {
+            return Err(invalid("name", "A rule needs a name."));
+        }
+        if self.name.len() > 200 || self.description.len() > MAX_TEXT {
+            return Err(invalid("name", "The name or description is too long."));
+        }
+        if self.actions.is_empty() {
+            return Err(invalid("actions", "A rule needs something to do."));
+        }
+        let dlp_actions = self.actions.iter().filter(|a| a.is_dlp()).count();
+        match self.kind {
+            Kind::Dlp => {
+                if self.direction != Direction::Outgoing {
+                    return Err(invalid("direction", "DLP rules check outgoing mail only."));
+                }
+                if dlp_actions != 1 || self.actions.len() != 1 {
+                    return Err(invalid(
+                        "actions",
+                        "A DLP rule has exactly one action: block, warn or hold.",
+                    ));
+                }
+            }
+            Kind::Transport => {
+                if dlp_actions > 0 {
+                    return Err(invalid(
+                        "actions",
+                        "Block, warn and hold belong to DLP rules.",
+                    ));
+                }
+                if self
+                    .conditions
+                    .iter()
+                    .chain(&self.exceptions)
+                    .any(|c| matches!(c, Condition::Detected { .. }))
+                {
+                    return Err(invalid("conditions", "Detectors belong to DLP rules."));
+                }
+            }
+        }
+        for (property, list) in [
+            ("conditions", &self.conditions),
+            ("exceptions", &self.exceptions),
+        ] {
+            for condition in list {
+                validate_condition(condition).map_err(|reason| invalid(property, reason))?;
+            }
+        }
+        for action in &self.actions {
+            validate_action(action).map_err(|reason| invalid("actions", reason))?;
+        }
+        Ok(())
+    }
+}
+
+fn nonempty_list<T>(list: &[T], what: &str) -> Result<(), String> {
+    if list.is_empty() {
+        Err(format!("The {what} list is empty."))
+    } else if list.len() > MAX_LIST {
+        Err(format!(
+            "The {what} list is longer than {MAX_LIST} entries."
+        ))
+    } else {
+        Ok(())
+    }
+}
+
+fn header_name(name: &str) -> Result<(), String> {
+    if !name.is_empty()
+        && name.len() <= 100
+        && name.bytes().all(|b| b.is_ascii_graphic() && b != b':')
+    {
+        Ok(())
+    } else {
+        Err(format!("\"{name}\" isn't a header name."))
+    }
+}
+
+fn text(value: &str, what: &str) -> Result<(), String> {
+    if value.trim().is_empty() {
+        Err(format!("The {what} is empty."))
+    } else if value.len() > MAX_TEXT {
+        Err(format!("The {what} is longer than {MAX_TEXT} bytes."))
+    } else {
+        Ok(())
+    }
+}
+
+fn validate_condition(condition: &Condition) -> Result<(), String> {
+    match condition {
+        Condition::SenderAddress { addresses } | Condition::RecipientAddress { addresses } => {
+            nonempty_list(addresses, "address")
+        }
+        Condition::SenderDomain { domains } | Condition::RecipientDomain { domains } => {
+            nonempty_list(domains, "domain")
+        }
+        Condition::SenderGroup { groups } | Condition::RecipientGroup { groups } => {
+            nonempty_list(groups, "group")
+        }
+        Condition::SenderTenant { tenants } => nonempty_list(tenants, "tenant"),
+        Condition::Words { words, at_least } => {
+            nonempty_list(words, "word")?;
+            if *at_least == 0 {
+                return Err("The least number of words must be 1 or more.".into());
+            }
+            words::WordList::new(words).map(|_| ())
+        }
+        Condition::Pattern { pattern, at_least } => {
+            if *at_least == 0 {
+                return Err("The least number of matches must be 1 or more.".into());
+            }
+            words::Pattern::new(pattern).map(|_| ())
+        }
+        Condition::Header {
+            name,
+            contains,
+            matches,
+        } => {
+            header_name(name)?;
+            if let Some(pattern) = matches {
+                words::Pattern::new(pattern)?;
+            }
+            if contains.is_some() && matches.is_some() {
+                return Err("A header condition is either contains or matches.".into());
+            }
+            Ok(())
+        }
+        Condition::AttachmentType { types } => nonempty_list(types, "type"),
+        Condition::AttachmentExtension { extensions } => nonempty_list(extensions, "extension"),
+        Condition::AttachmentName { pattern } => words::Pattern::new(pattern).map(|_| ()),
+        Condition::Detected { detectors } => {
+            nonempty_list(detectors, "detector")?;
+            for d in detectors {
+                if detectors::by_id(&d.id).is_none() {
+                    return Err(format!("There is no detector \"{}\".", d.id));
+                }
+                if d.at_least == 0 {
+                    return Err("A detector's least count must be 1 or more.".into());
+                }
+            }
+            Ok(())
+        }
+        Condition::RecipientOutside
+        | Condition::AttachmentSizeOver { .. }
+        | Condition::AttachmentCountOver { .. }
+        | Condition::CantBeInspected
+        | Condition::MessageSizeOver { .. } => Ok(()),
+    }
+}
+
+fn validate_action(action: &Action) -> Result<(), String> {
+    match action {
+        Action::AddDisclaimer { text: t, html, .. } => {
+            text(t, "disclaimer")?;
+            html.as_deref()
+                .map_or(Ok(()), |h| text(h, "disclaimer's HTML"))
+        }
+        Action::AddHeader { name, value } => {
+            header_name(name)?;
+            if value.len() > 998 || value.contains(['\r', '\n']) {
+                Err("A header value is one line of at most 998 characters.".into())
+            } else {
+                Ok(())
+            }
+        }
+        Action::RemoveHeader { name } => header_name(name),
+        Action::PrefixSubject { text: t } => text(t, "subject prefix"),
+        Action::AddRecipient { address } => {
+            if address.contains('@') {
+                Ok(())
+            } else {
+                Err(format!("\"{address}\" isn't an address."))
+            }
+        }
+        Action::Redirect { addresses } => {
+            nonempty_list(addresses, "address")?;
+            match addresses.iter().find(|a| !a.contains('@')) {
+                Some(a) => Err(format!("\"{a}\" isn't an address.")),
+                None => Ok(()),
+            }
+        }
+        Action::Refuse { text: t } => text(t, "refusal text"),
+        Action::Route { queue } => text(queue, "queue"),
+        Action::Block { notice } | Action::Warn { notice } | Action::Hold { notice, .. } => {
+            text(notice, "notice")
+        }
+    }
+}
+
+// --- Storage --------------------------------------------------------------
+
+struct Json<T>(T);
+
+impl<T: SerdeSerialize> Serialize for Json<T> {
+    fn serialize(&self) -> trc::Result<Vec<u8>> {
+        serde_json::to_vec(&self.0).map_err(|err| {
+            trc::StoreEvent::UnexpectedError
+                .into_err()
+                .details("Failed to serialize mail rule")
+                .reason(err)
+        })
+    }
+}
+
+impl<T: DeserializeOwned + Sync + Send> Deserialize for Json<T> {
+    fn deserialize(bytes: &[u8]) -> trc::Result<Self> {
+        serde_json::from_slice(bytes).map(Json).map_err(|err| {
+            trc::StoreEvent::DataCorruption
+                .into_err()
+                .details("Invalid mail rule")
+                .reason(err)
+        })
+    }
+}
+
+fn class(id: u32) -> ValueClass {
+    let mut key = Vec::with_capacity(6);
+    key.push(FEATURE);
+    key.push(KIND_RULE);
+    key.extend_from_slice(&id.to_be_bytes());
+    ValueClass::Any(AnyClass {
+        subspace: SUBSPACE_INBUXA,
+        key,
+    })
+}
+
+fn key(id: u32) -> ValueKey<ValueClass> {
+    ValueKey::from(class(id))
+}
+
+pub async fn get(data: &Store, id: u32) -> trc::Result<Option<Rule>> {
+    Ok(data
+        .get_value::<Json<Rule>>(key(id))
+        .await
+        .caused_by(trc::location!())?
+        .map(|Json(rule)| rule))
+}
+
+/// Every rule, in the order they run: by priority, then oldest first.
+pub async fn all(data: &Store) -> trc::Result<Vec<Rule>> {
+    let mut rules = Vec::new();
+    data.iterate(IterateParams::new(key(0), key(u32::MAX)), |_, value| {
+        if let Ok(Json(rule)) = Json::<Rule>::deserialize(value) {
+            rules.push(rule);
+        }
+        Ok(true)
+    })
+    .await
+    .caused_by(trc::location!())?;
+    rules.sort_by_key(|rule| (rule.priority, rule.id));
+    Ok(rules)
+}
+
+/// Writes a new rule under the next free id, which it returns. Two nodes
+/// creating rules at once can't take the same id: the key must be absent.
+pub async fn create(data: &Store, rule: &Rule) -> trc::Result<u32> {
+    let mut attempt = 0;
+    loop {
+        attempt += 1;
+        let id = all(data).await?.iter().map(|r| r.id).max().unwrap_or(0) + 1;
+        let stored = Rule { id, ..rule.clone() };
+        let mut batch = BatchBuilder::new();
+        batch.assert_value(class(id), AssertValue::None);
+        batch.set(class(id), Json(&stored).serialize()?);
+        match data.write(batch.build_all()).await {
+            Ok(_) => {
+                super::cache::invalidate();
+                return Ok(id);
+            }
+            Err(err)
+                if attempt < CREATE_ATTEMPTS
+                    && matches!(
+                        err.as_ref(),
+                        trc::EventType::Store(trc::StoreEvent::AssertValueFailed)
+                    ) => {}
+            Err(err) => return Err(err.caused_by(trc::location!())),
+        }
+    }
+}
+
+/// Replaces a stored rule (same id).
+pub async fn update(data: &Store, rule: &Rule) -> trc::Result<()> {
+    let mut batch = BatchBuilder::new();
+    batch.set(class(rule.id), Json(rule).serialize()?);
+    data.write(batch.build_all())
+        .await
+        .caused_by(trc::location!())?;
+    super::cache::invalidate();
+    Ok(())
+}
+
+pub async fn delete(data: &Store, id: u32) -> trc::Result<()> {
+    let mut batch = BatchBuilder::new();
+    batch.clear(class(id));
+    data.write(batch.build_all())
+        .await
+        .caused_by(trc::location!())?;
+    super::cache::invalidate();
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn rule(kind: Kind, actions: Vec<Action>) -> Rule {
+        Rule {
+            id: 0,
+            name: "Cards outside".into(),
+            description: String::new(),
+            kind,
+            enabled: true,
+            priority: 0,
+            direction: Direction::Outgoing,
+            conditions: vec![Condition::RecipientOutside],
+            exceptions: vec![],
+            actions,
+            stop_processing: false,
+            created_by: String::new(),
+            created_at: 0,
+            updated_at: 0,
+        }
+    }
+
+    #[test]
+    fn wire_format() {
+        let json = r#"{"name":"Cards","kind":"dlp","direction":"outgoing",
+            "conditions":[{"type":"recipientOutside"},{"type":"detected","detectors":[{"id":"payment-card","atLeast":5}]}],
+            "actions":[{"type":"hold","notice":"Held for review","notifySender":true}]}"#;
+        let parsed: Rule = serde_json::from_str(json).unwrap();
+        assert!(parsed.enabled);
+        assert_eq!(
+            parsed.conditions[1],
+            Condition::Detected {
+                detectors: vec![DetectorMin {
+                    id: "payment-card".into(),
+                    at_least: 5
+                }]
+            }
+        );
+        assert_eq!(
+            parsed.actions[0],
+            Action::Hold {
+                notice: "Held for review".into(),
+                notify_sender: true
+            }
+        );
+        assert!(parsed.validate().is_ok());
+        let back = serde_json::to_value(&parsed).unwrap();
+        assert_eq!(back["actions"][0]["notifySender"], true);
+    }
+
+    #[test]
+    fn dlp_rules_have_one_dlp_action_on_outgoing_mail() {
+        let block = Action::Block {
+            notice: "No.".into(),
+        };
+        assert!(rule(Kind::Dlp, vec![block.clone()]).validate().is_ok());
+        let two = rule(
+            Kind::Dlp,
+            vec![
+                block.clone(),
+                Action::Warn {
+                    notice: "Hm.".into(),
+                },
+            ],
+        );
+        assert_eq!(two.validate().unwrap_err().property, "actions");
+        let mixed = rule(
+            Kind::Dlp,
+            vec![block.clone(), Action::PrefixSubject { text: "[x]".into() }],
+        );
+        assert_eq!(mixed.validate().unwrap_err().property, "actions");
+        let mut inbound = rule(Kind::Dlp, vec![block.clone()]);
+        inbound.direction = Direction::Incoming;
+        assert_eq!(inbound.validate().unwrap_err().property, "direction");
+        assert_eq!(
+            rule(Kind::Transport, vec![block])
+                .validate()
+                .unwrap_err()
+                .property,
+            "actions"
+        );
+    }
+
+    #[test]
+    fn conditions_and_actions_are_checked() {
+        let disclaimer = Action::AddDisclaimer {
+            text: "Sent from Example Co.".into(),
+            html: None,
+            position: Position::Bottom,
+        };
+        let mut r = rule(Kind::Transport, vec![disclaimer]);
+        assert!(r.validate().is_ok());
+        r.conditions.push(Condition::Detected {
+            detectors: vec![DetectorMin {
+                id: "iban".into(),
+                at_least: 1,
+            }],
+        });
+        assert_eq!(r.validate().unwrap_err().property, "conditions");
+
+        let mut r = rule(
+            Kind::Dlp,
+            vec![Action::Block {
+                notice: "No.".into(),
+            }],
+        );
+        r.conditions = vec![Condition::Detected {
+            detectors: vec![DetectorMin {
+                id: "nope".into(),
+                at_least: 1,
+            }],
+        }];
+        assert!(r.validate().unwrap_err().reason.contains("nope"));
+        r.conditions = vec![Condition::Pattern {
+            pattern: "(".into(),
+            at_least: 1,
+        }];
+        assert!(r.validate().is_err());
+        r.conditions = vec![Condition::Words {
+            words: vec![],
+            at_least: 1,
+        }];
+        assert!(r.validate().is_err());
+        r.exceptions = vec![Condition::Header {
+            name: "X-Bad: yes".into(),
+            contains: None,
+            matches: None,
+        }];
+        r.conditions = vec![];
+        assert_eq!(r.validate().unwrap_err().property, "exceptions");
+
+        let header = rule(
+            Kind::Transport,
+            vec![Action::AddHeader {
+                name: "X-Tag".into(),
+                value: "a\r\nBcc: x@y".into(),
+            }],
+        );
+        assert!(header.validate().is_err());
+        let redirect = rule(
+            Kind::Transport,
+            vec![Action::Redirect {
+                addresses: vec!["nobody".into()],
+            }],
+        );
+        assert!(redirect.validate().is_err());
+        let mut unnamed = rule(
+            Kind::Transport,
+            vec![Action::RemoveHeader {
+                name: "X-Tag".into(),
+            }],
+        );
+        unnamed.name = " ".into();
+        assert_eq!(unnamed.validate().unwrap_err().property, "name");
+    }
+}

crates/jmap-proto/src/object/inbuxa_mail_rule.rs

@@ -0,0 +1,218 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! `inbuxa:MailRule/get` and `/set` under `urn:inbuxa:jmap`: mail flow rules
+//! and DLP rules (dlp-and-mail-flow-rules spec, §2.2). `kind` says which,
+//! and which permissions reach it. The set call's `reason` argument, if
+//! given, goes into the audit log with the change.
+
+use crate::{
+    object::{AnyId, JmapObject, JmapObjectId},
+    request::deserialize::DeserializeArguments,
+};
+use jmap_tools::{Element, Key, Property};
+use std::{borrow::Cow, str::FromStr};
+use types::id::Id;
+
+#[derive(Debug, Clone, Default)]
+pub struct MailRule;
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum MailRuleProperty {
+    Id,
+    Name,
+    Description,
+    /// `dlp` or `transport`.
+    Kind,
+    Enabled,
+    /// Lower runs first.
+    Priority,
+    /// `outgoing`, `incoming` or `any`.
+    Direction,
+    Conditions,
+    Exceptions,
+    Actions,
+    StopProcessing,
+    CreatedBy,
+    CreatedAt,
+    UpdatedAt,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum MailRuleValue {
+    Id(Id),
+}
+
+impl Property for MailRuleProperty {
+    fn try_parse(parent: Option<&Key<'_, Self>>, value: &str) -> Option<Self> {
+        // Keys inside conditions and actions stay plain keys
+        match parent {
+            None => MailRuleProperty::parse(value),
+            Some(_) => None,
+        }
+    }
+
+    fn to_cow(&self) -> Cow<'static, str> {
+        match self {
+            MailRuleProperty::Id => "id",
+            MailRuleProperty::Name => "name",
+            MailRuleProperty::Description => "description",
+            MailRuleProperty::Kind => "kind",
+            MailRuleProperty::Enabled => "enabled",
+            MailRuleProperty::Priority => "priority",
+            MailRuleProperty::Direction => "direction",
+            MailRuleProperty::Conditions => "conditions",
+            MailRuleProperty::Exceptions => "exceptions",
+            MailRuleProperty::Actions => "actions",
+            MailRuleProperty::StopProcessing => "stopProcessing",
+            MailRuleProperty::CreatedBy => "createdBy",
+            MailRuleProperty::CreatedAt => "createdAt",
+            MailRuleProperty::UpdatedAt => "updatedAt",
+        }
+        .into()
+    }
+}
+
+impl MailRuleProperty {
+    fn parse(value: &str) -> Option<Self> {
+        hashify::tiny_map!(value.as_bytes(),
+            b"id" => MailRuleProperty::Id,
+            b"name" => MailRuleProperty::Name,
+            b"description" => MailRuleProperty::Description,
+            b"kind" => MailRuleProperty::Kind,
+            b"enabled" => MailRuleProperty::Enabled,
+            b"priority" => MailRuleProperty::Priority,
+            b"direction" => MailRuleProperty::Direction,
+            b"conditions" => MailRuleProperty::Conditions,
+            b"exceptions" => MailRuleProperty::Exceptions,
+            b"actions" => MailRuleProperty::Actions,
+            b"stopProcessing" => MailRuleProperty::StopProcessing,
+            b"createdBy" => MailRuleProperty::CreatedBy,
+            b"createdAt" => MailRuleProperty::CreatedAt,
+            b"updatedAt" => MailRuleProperty::UpdatedAt,
+        )
+    }
+}
+
+impl FromStr for MailRuleProperty {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        MailRuleProperty::parse(s).ok_or(())
+    }
+}
+
+impl Element for MailRuleValue {
+    type Property = MailRuleProperty;
+
+    fn try_parse<P>(key: &Key<'_, Self::Property>, value: &str) -> Option<Self> {
+        match key {
+            Key::Property(MailRuleProperty::Id) => Id::from_str(value).ok().map(MailRuleValue::Id),
+            _ => None,
+        }
+    }
+
+    fn to_cow(&self) -> Cow<'static, str> {
+        match self {
+            MailRuleValue::Id(id) => id.to_string().into(),
+        }
+    }
+}
+
+/// The set call's own argument: why, for the audit log.
+#[derive(Debug, Clone, Default)]
+pub struct MailRuleSetArguments {
+    pub reason: Option<String>,
+}
+
+impl<'de> DeserializeArguments<'de> for MailRuleSetArguments {
+    fn deserialize_argument<A>(&mut self, key: &str, map: &mut A) -> Result<(), A::Error>
+    where
+        A: serde::de::MapAccess<'de>,
+    {
+        if key == "reason" {
+            self.reason = map.next_value()?;
+        } else {
+            let _ = map.next_value::<serde::de::IgnoredAny>()?;
+        }
+        Ok(())
+    }
+}
+
+impl JmapObject for MailRule {
+    type Property = MailRuleProperty;
+
+    type Element = MailRuleValue;
+
+    type Id = Id;
+
+    type Filter = ();
+
+    type Comparator = ();
+
+    type GetArguments = ();
+
+    type SetArguments<'de> = MailRuleSetArguments;
+
+    type QueryArguments = ();
+
+    type CopyArguments = ();
+
+    type ParseArguments = ();
+
+    const ID_PROPERTY: Self::Property = MailRuleProperty::Id;
+}
+
+impl From<Id> for MailRuleValue {
+    fn from(id: Id) -> Self {
+        MailRuleValue::Id(id)
+    }
+}
+
+impl JmapObjectId for MailRuleValue {
+    fn as_id(&self) -> Option<Id> {
+        match self {
+            MailRuleValue::Id(id) => Some(*id),
+        }
+    }
+
+    fn as_any_id(&self) -> Option<AnyId> {
+        match self {
+            MailRuleValue::Id(id) => Some(AnyId::Id(*id)),
+        }
+    }
+
+    fn as_id_ref(&self) -> Option<&str> {
+        None
+    }
+
+    fn try_set_id(&mut self, new_id: AnyId) -> bool {
+        if let AnyId::Id(id) = new_id {
+            *self = MailRuleValue::Id(id);
+            true
+        } else {
+            false
+        }
+    }
+}
+
+impl JmapObjectId for MailRuleProperty {
+    fn as_id(&self) -> Option<Id> {
+        None
+    }
+
+    fn as_any_id(&self) -> Option<AnyId> {
+        None
+    }
+
+    fn as_id_ref(&self) -> Option<&str> {
+        None
+    }
+
+    fn try_set_id(&mut self, _: AnyId) -> bool {
+        false
+    }
+}

crates/jmap-proto/src/object/mod.rs

@@ -28,6 +28,7 @@ pub mod inbuxa_data_inventory; // inbuxa: personal-data catalog
 pub mod inbuxa_inventory_snapshot; // inbuxa: personal-data catalog
 pub mod inbuxa_audit; // inbuxa: the audit log
 pub mod inbuxa_legal_hold; // inbuxa: legal hold
+pub mod inbuxa_mail_rule; // inbuxa: DLP and mail flow rules
 pub mod inbuxa_hold_export; // inbuxa: legal hold exports
 pub mod inbuxa_explanation; // inbuxa: "Explain this" with the local model
 pub mod inbuxa_protocol_policy; // inbuxa: legacy protocols off

crates/jmap-proto/src/references/eval.rs

@@ -82,6 +82,9 @@ impl Response<'_> {
                         GetResponseMethod::LegalHold(response) => {
                             response.eval_jptr(path, &mut results)
                         }
+                        GetResponseMethod::MailRule(response) => {
+                            response.eval_jptr(path, &mut results)
+                        }
                         GetResponseMethod::HoldExport(response) => {
                             response.eval_jptr(path, &mut results)
                         }

crates/jmap-proto/src/references/resolve.rs

@@ -53,6 +53,7 @@ impl Response<'_> {
                 GetRequestMethod::AuditSettings(request) => request.resolve_references(self)?,
                 GetRequestMethod::AccountLock(request) => request.resolve_references(self)?,
                 GetRequestMethod::LegalHold(request) => request.resolve_references(self)?,
+                GetRequestMethod::MailRule(request) => request.resolve_references(self)?,
                 GetRequestMethod::HoldExport(request) => request.resolve_references(self)?,
                 GetRequestMethod::ProtocolPolicy(request) => request.resolve_references(self)?,
                 GetRequestMethod::TenantProtocolPolicy(request) => {
@@ -122,6 +123,9 @@ impl Response<'_> {
                 SetRequestMethod::LegalHold(request) => {
                     request.resolve_references(self, 1, false)?
                 }
+                SetRequestMethod::MailRule(request) => {
+                    request.resolve_references(self, 1, false)?
+                }
                 SetRequestMethod::HoldExport(request) => {
                     request.resolve_references(self, 1, false)?
                 }

crates/jmap-proto/src/request/method.rs

@@ -65,6 +65,8 @@ pub enum MethodObject {
     LegalHold,
     HoldExport,
     ProtocolPolicy,
+    // inbuxa: DLP and mail flow rules
+    MailRule,
     TenantProtocolPolicy,
 }
 
@@ -102,7 +104,8 @@ impl MethodObject {
             | MethodObject::AuditVerification
             | MethodObject::AccountLock
             | MethodObject::LegalHold
-            | MethodObject::HoldExport => Capability::Inbuxa,
+            | MethodObject::HoldExport
+            | MethodObject::MailRule => Capability::Inbuxa,
             MethodObject::ProtocolPolicy => Capability::Inbuxa,
             MethodObject::TenantProtocolPolicy => Capability::Inbuxa,
         }
@@ -296,6 +299,8 @@ impl MethodName {
             (MethodFunction::Set, MethodObject::AccountLock) => "inbuxa:AccountLock/set",
             (MethodFunction::Get, MethodObject::LegalHold) => "inbuxa:LegalHold/get",
             (MethodFunction::Set, MethodObject::LegalHold) => "inbuxa:LegalHold/set",
+            (MethodFunction::Get, MethodObject::MailRule) => "inbuxa:MailRule/get",
+            (MethodFunction::Set, MethodObject::MailRule) => "inbuxa:MailRule/set",
             (MethodFunction::Get, MethodObject::HoldExport) => "inbuxa:HoldExport/get",
             (MethodFunction::Set, MethodObject::HoldExport) => "inbuxa:HoldExport/set",
             (MethodFunction::Set, MethodObject::AuditVerification) => {
@@ -448,6 +453,8 @@ impl MethodName {
             "inbuxa:AccountLock/set" => (MethodObject::AccountLock, MethodFunction::Set),
             "inbuxa:LegalHold/get" => (MethodObject::LegalHold, MethodFunction::Get),
             "inbuxa:LegalHold/set" => (MethodObject::LegalHold, MethodFunction::Set),
+            "inbuxa:MailRule/get" => (MethodObject::MailRule, MethodFunction::Get),
+            "inbuxa:MailRule/set" => (MethodObject::MailRule, MethodFunction::Set),
             "inbuxa:HoldExport/get" => (MethodObject::HoldExport, MethodFunction::Get),
             "inbuxa:HoldExport/set" => (MethodObject::HoldExport, MethodFunction::Set),
             "inbuxa:AuditVerification/set" => (MethodObject::AuditVerification, MethodFunction::Set),
@@ -518,6 +525,7 @@ impl Display for MethodObject {
             MethodObject::AuditVerification => "inbuxa:AuditVerification",
             MethodObject::AccountLock => "inbuxa:AccountLock",
             MethodObject::LegalHold => "inbuxa:LegalHold",
+            MethodObject::MailRule => "inbuxa:MailRule",
             MethodObject::HoldExport => "inbuxa:HoldExport",
             MethodObject::ProtocolPolicy => "inbuxa:ProtocolPolicy",
             MethodObject::TenantProtocolPolicy => "inbuxa:TenantProtocolPolicy",

crates/jmap-proto/src/request/mod.rs

@@ -123,6 +123,7 @@ pub enum GetRequestMethod {
     AuditSettings(Box<GetRequest<crate::object::inbuxa_audit::AuditSettings>>),
     AccountLock(Box<GetRequest<crate::object::inbuxa_account_lock::AccountLock>>),
     LegalHold(Box<GetRequest<crate::object::inbuxa_legal_hold::LegalHold>>),
+    MailRule(Box<GetRequest<crate::object::inbuxa_mail_rule::MailRule>>),
     HoldExport(Box<GetRequest<crate::object::inbuxa_hold_export::HoldExport>>),
     ProtocolPolicy(Box<GetRequest<crate::object::inbuxa_protocol_policy::ProtocolPolicy>>),
     TenantProtocolPolicy(
@@ -158,6 +159,7 @@ pub enum SetRequestMethod<'x> {
     AuditVerification(Box<SetRequest<'x, crate::object::inbuxa_audit::AuditVerification>>),
     AccountLock(Box<SetRequest<'x, crate::object::inbuxa_account_lock::AccountLock>>),
     LegalHold(Box<SetRequest<'x, crate::object::inbuxa_legal_hold::LegalHold>>),
+    MailRule(Box<SetRequest<'x, crate::object::inbuxa_mail_rule::MailRule>>),
     HoldExport(Box<SetRequest<'x, crate::object::inbuxa_hold_export::HoldExport>>),
     ProtocolPolicy(Box<SetRequest<'x, crate::object::inbuxa_protocol_policy::ProtocolPolicy>>),
     TenantProtocolPolicy(

crates/jmap-proto/src/request/parser.rs

@@ -609,6 +609,21 @@ impl<'de> Visitor<'de> for CallVisitor {
                     return Err(de::Error::invalid_length(1, &self));
                 }
             },
+            // inbuxa: DLP and mail flow rules
+            (MethodFunction::Get, MethodObject::MailRule) => match seq.next_element() {
+                Ok(Some(value)) => RequestMethod::Get(GetRequestMethod::MailRule(value)),
+                Err(err) => RequestMethod::invalid(err),
+                Ok(None) => {
+                    return Err(de::Error::invalid_length(1, &self));
+                }
+            },
+            (MethodFunction::Set, MethodObject::MailRule) => match seq.next_element() {
+                Ok(Some(value)) => RequestMethod::Set(SetRequestMethod::MailRule(value)),
+                Err(err) => RequestMethod::invalid(err),
+                Ok(None) => {
+                    return Err(de::Error::invalid_length(1, &self));
+                }
+            },
             // inbuxa: legal hold
             (MethodFunction::Get, MethodObject::LegalHold) => match seq.next_element() {
                 Ok(Some(value)) => RequestMethod::Get(GetRequestMethod::LegalHold(value)),

crates/jmap-proto/src/response/mod.rs

@@ -110,6 +110,7 @@ pub enum GetResponseMethod {
     AuditSettings(GetResponse<crate::object::inbuxa_audit::AuditSettings>),
     AccountLock(GetResponse<crate::object::inbuxa_account_lock::AccountLock>),
     LegalHold(GetResponse<crate::object::inbuxa_legal_hold::LegalHold>),
+    MailRule(GetResponse<crate::object::inbuxa_mail_rule::MailRule>),
     HoldExport(GetResponse<crate::object::inbuxa_hold_export::HoldExport>),
     ProtocolPolicy(GetResponse<crate::object::inbuxa_protocol_policy::ProtocolPolicy>),
     TenantProtocolPolicy(
@@ -145,6 +146,7 @@ pub enum SetResponseMethod {
     AuditVerification(Box<SetResponse<crate::object::inbuxa_audit::AuditVerification>>),
     AccountLock(Box<SetResponse<crate::object::inbuxa_account_lock::AccountLock>>),
     LegalHold(Box<SetResponse<crate::object::inbuxa_legal_hold::LegalHold>>),
+    MailRule(Box<SetResponse<crate::object::inbuxa_mail_rule::MailRule>>),
     HoldExport(Box<SetResponse<crate::object::inbuxa_hold_export::HoldExport>>),
     Explanation(Box<SetResponse<crate::object::inbuxa_explanation::Explanation>>),
     ProtocolPolicy(Box<SetResponse<crate::object::inbuxa_protocol_policy::ProtocolPolicy>>),
@@ -799,6 +801,18 @@ impl<'x> From<SetResponse<crate::object::inbuxa_account_lock::AccountLock>> for
 }
 
 // inbuxa: legal hold
+impl<'x> From<GetResponse<crate::object::inbuxa_mail_rule::MailRule>> for ResponseMethod<'x> {
+    fn from(value: GetResponse<crate::object::inbuxa_mail_rule::MailRule>) -> Self {
+        ResponseMethod::Get(GetResponseMethod::MailRule(value))
+    }
+}
+
+impl<'x> From<SetResponse<crate::object::inbuxa_mail_rule::MailRule>> for ResponseMethod<'x> {
+    fn from(value: SetResponse<crate::object::inbuxa_mail_rule::MailRule>) -> Self {
+        ResponseMethod::Set(SetResponseMethod::MailRule(Box::new(value)))
+    }
+}
+
 impl<'x> From<GetResponse<crate::object::inbuxa_legal_hold::LegalHold>> for ResponseMethod<'x> {
     fn from(value: GetResponse<crate::object::inbuxa_legal_hold::LegalHold>) -> Self {
         ResponseMethod::Get(GetResponseMethod::LegalHold(value))

crates/jmap/src/api/auth.rs

@@ -103,6 +103,16 @@ impl JmapAuthorization for AccessToken {
                 // inbuxa: account lock (AL-12)
                 GetRequestMethod::AccountLock(_) => Permission::SysAccountLockGet,
                 GetRequestMethod::LegalHold(_) => Permission::SysLegalHoldGet,
+                // inbuxa: DLP and mail flow rules share an object; either
+                // permission reaches it, and the handler shows each kind
+                // only to those who may see it
+                GetRequestMethod::MailRule(_) => {
+                    if self.has_permission(Permission::SysMailRuleGet) {
+                        Permission::SysMailRuleGet
+                    } else {
+                        Permission::SysDlpPolicyGet
+                    }
+                }
                 GetRequestMethod::HoldExport(_) => Permission::SysLegalHoldExport,
                 // inbuxa: legacy protocols off. It takes listeners away and
                 // puts them back, so it takes the listener's permissions
@@ -247,6 +257,19 @@ impl JmapAuthorization for AccessToken {
                         Permission::SysLegalHoldUpdate,
                         Permission::SysLegalHoldUpdate,
                     ),
+                    // inbuxa: DLP and mail flow rules: either change
+                    // permission gets in; the handler checks each rule's kind
+                    SetRequestMethod::MailRule(_) => {
+                        if self.has_permission(Permission::SysMailRuleUpdate)
+                            || self.has_permission(Permission::SysDlpPolicyUpdate)
+                        {
+                            Ok(())
+                        } else {
+                            Err(trc::JmapEvent::Forbidden
+                                .into_err()
+                                .details("You are not authorized to change mail rules"))
+                        }
+                    }
                     // inbuxa: LH-12, exporting held data
                     SetRequestMethod::HoldExport(s) => validate_set(
                         s,
@@ -407,6 +430,7 @@ impl JmapAuthorization for AccessToken {
                 | MethodObject::AccountLock
                 | MethodObject::LegalHold
                 | MethodObject::HoldExport
+                | MethodObject::MailRule
                 | MethodObject::ProtocolPolicy
                 | MethodObject::TenantProtocolPolicy => Permission::JmapEmailChanges,
                 // inbuxa: x:MaskedEmail/changes reads what /get reads

crates/jmap/src/api/request.rs

@@ -279,6 +279,9 @@ impl RequestHandler for Server {
                                     SetResponseMethod::LegalHold(set_response) => {
                                         set_response.update_created_ids(&mut response);
                                     }
+                                    SetResponseMethod::MailRule(set_response) => {
+                                        set_response.update_created_ids(&mut response);
+                                    }
                                     SetResponseMethod::HoldExport(set_response) => {
                                         set_response.update_created_ids(&mut response);
                                     }
@@ -486,6 +489,11 @@ impl RequestHandler for Server {
                     resolve_account_id(&mut req.account_id, method_name.obj, access_token)?;
                     crate::inbuxa::legal_hold::get(self, *req).await?.into()
                 }
+                // inbuxa: DLP and mail flow rules
+                GetRequestMethod::MailRule(mut req) => {
+                    resolve_account_id(&mut req.account_id, method_name.obj, access_token)?;
+                    crate::inbuxa::mail_rule::get(self, access_token, *req).await?.into()
+                }
                 // inbuxa: the audit log (AU-9)
                 GetRequestMethod::AuditEvent(mut req) => {
                     resolve_account_id(&mut req.account_id, method_name.obj, access_token)?;
@@ -910,6 +918,22 @@ impl RequestHandler for Server {
                     .await?
                     .into()
                 }
+                SetRequestMethod::MailRule(mut req) => {
+                    resolve_account_id(&mut req.account_id, method_name.obj, access_token)?;
+                    let reason = req.arguments.reason.clone();
+                    crate::inbuxa::audit::recorded(
+                        self,
+                        access_token,
+                        session,
+                        &method_name.obj.to_string(),
+                        None,
+                        reason,
+                        *req,
+                        |req| Box::pin(crate::inbuxa::mail_rule::set(self, access_token, req)),
+                    )
+                    .await?
+                    .into()
+                }
                 SetRequestMethod::AuditExport(mut req) => {
                     resolve_account_id(&mut req.account_id, method_name.obj, access_token)?;
                     crate::inbuxa::audit_log::export_set(self, access_token, session, *req)

crates/jmap/src/changes/get.rs

@@ -429,6 +429,7 @@ impl IntermediateChangesResponse {
             | MethodObject::AccountLock
             | MethodObject::LegalHold
             | MethodObject::HoldExport
+            | MethodObject::MailRule
             | MethodObject::ProtocolPolicy
             | MethodObject::TenantProtocolPolicy
             | MethodObject::Registry(_) => unreachable!(),

crates/jmap/src/inbuxa/mail_rule.rs

@@ -0,0 +1,327 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! `inbuxa:MailRule` (dlp-and-mail-flow-rules spec, §2.2, §2.8): mail flow
+//! rules and DLP rules. One object, two kinds, each with its own
+//! permissions: `sysMailRuleGet`/`Update` for transport rules,
+//! `sysDlpPolicyGet`/`Update` for DLP rules. Rules are the server's: nobody
+//! in a tenant reaches them (settled answer 3). The request layer records
+//! every change in the audit log.
+
+use common::{Server, auth::AccessToken};
+use inbuxa_features::mailflow::rules::{self, Kind, Rule};
+use jmap_proto::{
+    error::set::SetError,
+    method::{
+        get::{GetRequest, GetResponse},
+        set::{SetRequest, SetResponse},
+    },
+    object::inbuxa_mail_rule::{MailRule, MailRuleProperty as P, MailRuleValue},
+    request::IntoValid,
+    types::date::UTCDate,
+};
+use jmap_tools::{Key, Map, Property, Value};
+use registry::schema::enums::Permission;
+use std::borrow::Cow;
+use store::write::now;
+use types::id::Id;
+
+type RValue = Value<'static, P, MailRuleValue>;
+
+const ALL: &[P] = &[
+    P::Id,
+    P::Name,
+    P::Description,
+    P::Kind,
+    P::Enabled,
+    P::Priority,
+    P::Direction,
+    P::Conditions,
+    P::Exceptions,
+    P::Actions,
+    P::StopProcessing,
+    P::CreatedBy,
+    P::CreatedAt,
+    P::UpdatedAt,
+];
+
+/// Properties the server sets; a client that sends them is refused.
+const SERVER_SET: &[P] = &[P::Id, P::CreatedBy, P::CreatedAt, P::UpdatedAt];
+
+fn can_see(access_token: &AccessToken, kind: Kind) -> bool {
+    access_token.has_permission(match kind {
+        Kind::Dlp => Permission::SysDlpPolicyGet,
+        Kind::Transport => Permission::SysMailRuleGet,
+    })
+}
+
+fn can_change(access_token: &AccessToken, kind: Kind) -> bool {
+    access_token.has_permission(match kind {
+        Kind::Dlp => Permission::SysDlpPolicyUpdate,
+        Kind::Transport => Permission::SysMailRuleUpdate,
+    })
+}
+
+fn server_level(access_token: &AccessToken) -> trc::Result<()> {
+    if access_token.tenant_id().is_some() {
+        Err(trc::JmapEvent::Forbidden
+            .into_err()
+            .details("Mail rules are the server's."))
+    } else {
+        Ok(())
+    }
+}
+
+fn json_to_value(json: serde_json::Value) -> RValue {
+    match json {
+        serde_json::Value::Null => Value::Null,
+        serde_json::Value::Bool(b) => Value::Bool(b),
+        serde_json::Value::Number(n) => {
+            if let Some(n) = n.as_u64() {
+                Value::Number(n.into())
+            } else if let Some(n) = n.as_i64() {
+                Value::Number(n.into())
+            } else {
+                Value::Number(n.as_f64().unwrap_or_default().into())
+            }
+        }
+        serde_json::Value::String(s) => Value::Str(Cow::Owned(s)),
+        serde_json::Value::Array(items) => {
+            Value::Array(items.into_iter().map(json_to_value).collect())
+        }
+        serde_json::Value::Object(map) => {
+            let mut out = Map::with_capacity(map.len());
+            for (key, value) in map {
+                out.insert_unchecked(Key::Owned(key), json_to_value(value));
+            }
+            Value::Object(out)
+        }
+    }
+}
+
+fn date(seconds: u64) -> RValue {
+    Value::Str(UTCDate::from_timestamp(seconds as i64).to_string().into())
+}
+
+fn to_value(rule: &Rule, properties: &[P]) -> RValue {
+    let json = serde_json::to_value(rule).unwrap_or_default();
+    let mut out = Map::with_capacity(properties.len());
+    for property in properties {
+        let value = match property {
+            P::Id => Value::Element(MailRuleValue::Id(Id::from(rule.id))),
+            P::CreatedAt => date(rule.created_at),
+            P::UpdatedAt => date(rule.updated_at),
+            other => json
+                .get(other.to_cow().as_ref())
+                .cloned()
+                .map_or(Value::Null, json_to_value),
+        };
+        out.insert_unchecked(Key::Property(property.clone()), value);
+    }
+    Value::Object(out)
+}
+
+/// A rule as sent: its JSON object, top-level keys only those a client may
+/// set.
+fn client_json(value: Value<'_, P, MailRuleValue>) -> Result<serde_json::Map<String, serde_json::Value>, SetError<P>> {
+    let mut map = serde_json::Map::new();
+    for (key, value) in value.into_expanded_object() {
+        match &key {
+            Key::Property(p) if SERVER_SET.contains(p) => {
+                return Err(SetError::invalid_properties()
+                    .with_property(p.clone())
+                    .with_description("The server sets this."));
+            }
+            Key::Property(p) => {
+                map.insert(p.to_cow().into_owned(), value.into());
+            }
+            _ => {
+                return Err(SetError::invalid_properties().with_property(key.clone().into_owned()));
+            }
+        }
+    }
+    Ok(map)
+}
+
+fn parse(json: serde_json::Map<String, serde_json::Value>) -> Result<Rule, SetError<P>> {
+    let rule: Rule = serde_json::from_value(serde_json::Value::Object(json)).map_err(|err| {
+        SetError::invalid_properties().with_description(format!("Not a valid rule: {err}"))
+    })?;
+    rule.validate().map_err(|invalid| {
+        let property = invalid.property.parse::<P>().unwrap_or(P::Name);
+        SetError::invalid_properties()
+            .with_property(property)
+            .with_description(invalid.reason)
+    })?;
+    Ok(rule)
+}
+
+fn forbidden(kind: Kind) -> SetError<P> {
+    SetError::forbidden().with_description(match kind {
+        Kind::Dlp => "Changing DLP rules needs the permission to change DLP rules.",
+        Kind::Transport => "Changing mail flow rules needs the permission to change them.",
+    })
+}
+
+fn rule_id(id: Id) -> Option<u32> {
+    u32::try_from(id.id()).ok()
+}
+
+/// `inbuxa:MailRule/get`: the rules the caller may see, in the order they
+/// run.
+pub async fn get(
+    server: &Server,
+    access_token: &AccessToken,
+    mut request: GetRequest<MailRule>,
+) -> trc::Result<GetResponse<MailRule>> {
+    server_level(access_token)?;
+    let properties = request.unwrap_properties(ALL);
+    let (ids, not_found) = request.unwrap_ids(server.core.jmap.get_max_objects)?;
+    let mut response = GetResponse {
+        account_id: request.account_id.into(),
+        state: None,
+        list: Vec::new(),
+        not_found,
+    };
+    let visible: Vec<Rule> = rules::all(server.store())
+        .await?
+        .into_iter()
+        .filter(|rule| can_see(access_token, rule.kind))
+        .collect();
+    match ids {
+        None => {
+            response.list = visible
+                .iter()
+                .map(|rule| to_value(rule, &properties))
+                .collect()
+        }
+        Some(ids) => {
+            for id in ids {
+                match rule_id(id).and_then(|id| visible.iter().find(|r| r.id == id)) {
+                    Some(rule) => response.list.push(to_value(rule, &properties)),
+                    None => response.push_not_found(id),
+                }
+            }
+        }
+    }
+    Ok(response)
+}
+
+/// `inbuxa:MailRule/set`: create, change or delete rules, each checked
+/// against the permissions for its kind (and, on a change of kind, both).
+pub async fn set(
+    server: &Server,
+    access_token: &AccessToken,
+    mut request: SetRequest<'_, MailRule>,
+) -> trc::Result<SetResponse<MailRule>> {
+    server_level(access_token)?;
+    let mut response = SetResponse::from_request(&request, server.core.jmap.set_max_objects)?;
+    let data = server.store();
+    let actor = server.audit_actor(access_token).await;
+
+    for (client_id, value) in request.unwrap_create() {
+        let rule = match client_json(value).and_then(parse) {
+            Ok(rule) => rule,
+            Err(error) => {
+                response.not_created.append(client_id, error);
+                continue;
+            }
+        };
+        if !can_change(access_token, rule.kind) {
+            response.not_created.append(client_id, forbidden(rule.kind));
+            continue;
+        }
+        let at = now();
+        let rule = Rule {
+            created_by: actor.name.clone(),
+            created_at: at,
+            updated_at: at,
+            ..rule
+        };
+        let id = rules::create(data, &rule).await?;
+        let mut out = Map::with_capacity(1);
+        out.insert_unchecked(
+            Key::Property(P::Id),
+            Value::Element(MailRuleValue::Id(Id::from(id))),
+        );
+        response.created.insert(client_id, Value::Object(out));
+    }
+
+    for (id, value) in request.unwrap_update().into_valid() {
+        let Some(current) = (match rule_id(id) {
+            Some(rule_id) => rules::get(data, rule_id).await?,
+            None => None,
+        }) else {
+            response.not_updated.append(id, SetError::not_found());
+            continue;
+        };
+        if !can_see(access_token, current.kind) {
+            response.not_updated.append(id, SetError::not_found());
+            continue;
+        }
+        if !can_change(access_token, current.kind) {
+            response.not_updated.append(id, forbidden(current.kind));
+            continue;
+        }
+        // The stored rule, with each property sent replacing its own
+        let mut json = match serde_json::to_value(&current) {
+            Ok(serde_json::Value::Object(map)) => map,
+            _ => serde_json::Map::new(),
+        };
+        let changes = match client_json(value) {
+            Ok(changes) => changes,
+            Err(error) => {
+                response.not_updated.append(id, error);
+                continue;
+            }
+        };
+        json.extend(changes);
+        let next = match parse(json) {
+            Ok(next) => next,
+            Err(error) => {
+                response.not_updated.append(id, error);
+                continue;
+            }
+        };
+        if next.kind != current.kind && !can_change(access_token, next.kind) {
+            response.not_updated.append(id, forbidden(next.kind));
+            continue;
+        }
+        let next = Rule {
+            id: current.id,
+            created_by: current.created_by.clone(),
+            created_at: current.created_at,
+            updated_at: now(),
+            ..next
+        };
+        if next != current {
+            rules::update(data, &next).await?;
+        }
+        response.updated.append(id, None);
+    }
+
+    for id in request.unwrap_destroy().into_valid() {
+        let Some(current) = (match rule_id(id) {
+            Some(rule_id) => rules::get(data, rule_id).await?,
+            None => None,
+        }) else {
+            response.not_destroyed.append(id, SetError::not_found());
+            continue;
+        };
+        if !can_see(access_token, current.kind) {
+            response.not_destroyed.append(id, SetError::not_found());
+            continue;
+        }
+        if !can_change(access_token, current.kind) {
+            response.not_destroyed.append(id, forbidden(current.kind));
+            continue;
+        }
+        rules::delete(data, current.id).await?;
+        response.destroyed.push(id);
+    }
+
+    Ok(response)
+}

crates/jmap/src/inbuxa/mod.rs

@@ -10,6 +10,7 @@
 pub mod access;
 pub mod account_lock;
 pub mod legal_hold;
+pub mod mail_rule;
 pub mod hold_export;
 pub mod hold_export_api;
 pub mod audit;

crates/registry/src/schema/enums.rs

@@ -1748,6 +1748,13 @@ pub enum Permission {
     SysLegalHoldExport = 672,
     // inbuxa: personal-data catalog, the data inventory and compliance overview
     SysComplianceGet = 673,
+    // inbuxa: DLP and mail flow rules
+    SysMailRuleGet = 674,
+    SysMailRuleUpdate = 675,
+    SysDlpPolicyGet = 676,
+    SysDlpPolicyUpdate = 677,
+    SysDlpReviewGet = 678,
+    SysDlpReviewUpdate = 679,
     SysAccountGet = 219,
     SysAccountCreate = 220,
     SysAccountUpdate = 221,

crates/registry/src/schema/enums_impl.rs

@@ -7091,6 +7091,12 @@ impl EnumImpl for Permission {
             b"sysLegalHoldUpdate" => Permission::SysLegalHoldUpdate,
             b"sysLegalHoldExport" => Permission::SysLegalHoldExport,
             b"sysComplianceGet" => Permission::SysComplianceGet,
+            b"sysMailRuleGet" => Permission::SysMailRuleGet,
+            b"sysMailRuleUpdate" => Permission::SysMailRuleUpdate,
+            b"sysDlpPolicyGet" => Permission::SysDlpPolicyGet,
+            b"sysDlpPolicyUpdate" => Permission::SysDlpPolicyUpdate,
+            b"sysDlpReviewGet" => Permission::SysDlpReviewGet,
+            b"sysDlpReviewUpdate" => Permission::SysDlpReviewUpdate,
             b"sysAccountGet" => Permission::SysAccountGet,
             b"sysAccountCreate" => Permission::SysAccountCreate,
             b"sysAccountUpdate" => Permission::SysAccountUpdate,
@@ -7781,6 +7787,12 @@ impl EnumImpl for Permission {
             Permission::SysLegalHoldUpdate => "sysLegalHoldUpdate",
             Permission::SysLegalHoldExport => "sysLegalHoldExport",
             Permission::SysComplianceGet => "sysComplianceGet",
+            Permission::SysMailRuleGet => "sysMailRuleGet",
+            Permission::SysMailRuleUpdate => "sysMailRuleUpdate",
+            Permission::SysDlpPolicyGet => "sysDlpPolicyGet",
+            Permission::SysDlpPolicyUpdate => "sysDlpPolicyUpdate",
+            Permission::SysDlpReviewGet => "sysDlpReviewGet",
+            Permission::SysDlpReviewUpdate => "sysDlpReviewUpdate",
             Permission::SysAccountGet => "sysAccountGet",
             Permission::SysAccountCreate => "sysAccountCreate",
             Permission::SysAccountUpdate => "sysAccountUpdate",
@@ -8464,6 +8476,12 @@ impl EnumImpl for Permission {
             671 => Some(Permission::SysLegalHoldUpdate),
             672 => Some(Permission::SysLegalHoldExport),
             673 => Some(Permission::SysComplianceGet),
+            674 => Some(Permission::SysMailRuleGet),
+            675 => Some(Permission::SysMailRuleUpdate),
+            676 => Some(Permission::SysDlpPolicyGet),
+            677 => Some(Permission::SysDlpPolicyUpdate),
+            678 => Some(Permission::SysDlpReviewGet),
+            679 => Some(Permission::SysDlpReviewUpdate),
             219 => Some(Permission::SysAccountGet),
             220 => Some(Permission::SysAccountCreate),
             221 => Some(Permission::SysAccountUpdate),
@@ -8908,7 +8926,7 @@ impl EnumImpl for Permission {
         }
     }
 
-    const COUNT: usize = 674;
+    const COUNT: usize = 680;
 }
 
 impl serde::Serialize for Permission {

resources/privacy/catalog.toml

@@ -79,6 +79,21 @@ lockedAt = ["metadata"]
 lockedBy = ["identifier"]
 delegates = ["identifier"]
 
+[object."inbuxa:MailRule"]
+file = "inbuxa_mail_rule.rs"
+default = "none"
+whose = ["administrator", "holder", "correspondent"]
+where = ["data-store"]
+scope = "server"
+retention = "unbounded"
+[object."inbuxa:MailRule".properties]
+name = ["content"]
+description = ["content"]
+conditions = ["contact", "content"]
+exceptions = ["contact", "content"]
+actions = ["contact", "content"]
+createdBy = ["identifier"]
+
 [object."inbuxa:LegalHold"]
 file = "inbuxa_legal_hold.rs"
 default = "none"

resources/schema/schema.json.sha256

@@ -1 +1 @@
-k496pjVWlQ2p4bkZCh8agzaCKMLD4c3Z9WtoxpckYDU
+yF7PlBR3UBqxlabhW5zZ5WacQWsynG1wNYEiJVAl6w4

tests/src/system/mail_rules.rs

@@ -0,0 +1,201 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+//! `inbuxa:MailRule` (dlp-and-mail-flow-rules spec, §2.2, §2.8): rules are
+//! stored, listed in the order they run, checked when written, kept apart
+//! by kind for permissions, and every change is audited.
+
+use crate::utils::{
+    account::Account,
+    server::{TestServer, TestServerBuilder},
+};
+use registry::schema::{
+    prelude::{ObjectType, Property},
+    structs::{CustomRoles, Role, UserRoles},
+};
+use registry::types::map::Map;
+use serde_json::{Value, json};
+
+const USING: &[&str] = &[
+    "urn:ietf:params:jmap:core",
+    "urn:inbuxa:jmap",
+    "urn:inbuxa:jmap:registry",
+];
+
+async fn call(account: &Account, method: &str, mut arguments: Value) -> (String, Value) {
+    if arguments.get("accountId").is_none() {
+        arguments["accountId"] = account.id_string().into();
+    }
+    let response = account.jmap_request(USING, json!([[method, arguments, "0"]])).await;
+    let call = response
+        .0
+        .pointer("/methodResponses/0")
+        .cloned()
+        .unwrap_or_else(|| panic!("{method}: {}", response.0));
+    (call[0].as_str().unwrap_or_default().to_string(), call[1].clone())
+}
+
+fn dlp_rule() -> Value {
+    json!({
+        "name": "Cards leaving",
+        "kind": "dlp",
+        "direction": "outgoing",
+        "priority": 10,
+        "conditions": [
+            {"type": "recipientOutside"},
+            {"type": "detected", "detectors": [{"id": "payment-card", "atLeast": 5}]}
+        ],
+        "actions": [{"type": "hold", "notice": "Held for review", "notifySender": true}]
+    })
+}
+
+fn transport_rule() -> Value {
+    json!({
+        "name": "Disclaimer",
+        "kind": "transport",
+        "direction": "outgoing",
+        "priority": 1,
+        "conditions": [{"type": "recipientOutside"}],
+        "actions": [{"type": "addDisclaimer", "text": "Sent by Example Co.", "position": "bottom"}]
+    })
+}
+
+async fn names(account: &Account) -> Vec<String> {
+    let (name, response) = call(account, "inbuxa:MailRule/get", json!({"ids": null})).await;
+    assert_eq!(name, "inbuxa:MailRule/get", "{response}");
+    response["list"]
+        .as_array()
+        .unwrap()
+        .iter()
+        .map(|r| r["name"].as_str().unwrap().to_string())
+        .collect()
+}
+
+pub async fn test(test: &mut TestServer) {
+    println!("Running mail rule tests...");
+    let admin = test.account("[email protected]");
+
+    // Created, then listed in the order they run
+    let (_, response) = call(
+        &admin,
+        "inbuxa:MailRule/set",
+        json!({"create": {"d": dlp_rule(), "t": transport_rule()}}),
+    )
+    .await;
+    let dlp_id = response["created"]["d"]["id"]
+        .as_str()
+        .unwrap_or_else(|| panic!("DLP rule created: {response}"))
+        .to_string();
+    let transport_id = response["created"]["t"]["id"].as_str().unwrap().to_string();
+    assert_eq!(names(&admin).await, vec!["Disclaimer", "Cards leaving"]);
+
+    let (_, response) = call(&admin, "inbuxa:MailRule/get", json!({"ids": [dlp_id]})).await;
+    let rule = &response["list"][0];
+    assert_eq!(rule["conditions"][1]["detectors"][0]["atLeast"], 5, "{rule}");
+    assert_eq!(rule["actions"][0]["notifySender"], true);
+    assert_eq!(rule["createdBy"], "[email protected]");
+    assert!(rule["createdAt"].as_str().is_some_and(|d| d.ends_with('Z')), "{rule}");
+
+    // Checked when written
+    let mut inbound = dlp_rule();
+    inbound["direction"] = "incoming".into();
+    let mut unknown = dlp_rule();
+    unknown["conditions"][1]["detectors"][0]["id"] = "no-such-detector".into();
+    let (_, response) = call(
+        &admin,
+        "inbuxa:MailRule/set",
+        json!({"create": {"a": inbound, "b": unknown, "c": {"name": "x", "kind": "dlp"}}}),
+    )
+    .await;
+    assert_eq!(response["notCreated"]["a"]["properties"][0], "direction", "{response}");
+    assert!(
+        response["notCreated"]["b"]["description"].as_str().unwrap().contains("no-such-detector"),
+        "{response}"
+    );
+    assert!(response["notCreated"].get("c").is_some(), "{response}");
+
+    // Changed in place; what the server sets can't be sent
+    let (_, response) = call(
+        &admin,
+        "inbuxa:MailRule/set",
+        json!({"update": {
+            transport_id.as_str(): {"name": "Footer", "priority": 50},
+            dlp_id.as_str(): {"createdBy": "someone else"}
+        }}),
+    )
+    .await;
+    assert!(response["updated"].get(transport_id.as_str()).is_some(), "{response}");
+    assert_eq!(response["notUpdated"][dlp_id.as_str()]["properties"][0], "createdBy", "{response}");
+    assert_eq!(names(&admin).await, vec!["Cards leaving", "Footer"]);
+
+    // A compliance officer sees DLP rules, not mail flow rules, and changes
+    // neither (settled answer 4)
+    let mut officer_role = None;
+    for id in admin
+        .registry_query_ids(ObjectType::Role, Vec::<(&str, &str)>::new(), Vec::<&str>::new())
+        .await
+    {
+        let role = admin.registry_get::<Role>(id).await;
+        if role.description == "Compliance Officer" && role.member_tenant_id.is_none() {
+            officer_role = Some(id);
+        }
+    }
+    let officer = admin
+        .create_user_account("[email protected]", "officer-secret-7731", "Officer", &[], vec![])
+        .await;
+    admin
+        .registry_update_object(
+            ObjectType::Account,
+            officer.id(),
+            json!({Property::Roles: UserRoles::Custom(CustomRoles {
+                role_ids: Map::new(vec![officer_role.expect("the officer role")]),
+            })}),
+        )
+        .await;
+    assert_eq!(names(&officer).await, vec!["Cards leaving"]);
+    let (name, response) =
+        call(&officer, "inbuxa:MailRule/set", json!({"create": {"d": dlp_rule()}})).await;
+    assert_eq!(name, "error", "the officer created a DLP rule: {response}");
+
+    // Deleted
+    let (_, response) = call(
+        &admin,
+        "inbuxa:MailRule/set",
+        json!({"destroy": [transport_id]}),
+    )
+    .await;
+    assert_eq!(response["destroyed"][0], transport_id.as_str(), "{response}");
+    assert_eq!(names(&admin).await, vec!["Cards leaving"]);
+
+    // Every change is in the audit log
+    let (_, response) = call(
+        &admin,
+        "inbuxa:AuditEvent/query",
+        json!({"filter": {"targetKind": "inbuxa:MailRule"}, "calculateTotal": true}),
+    )
+    .await;
+    assert!(
+        response["total"].as_u64().unwrap_or(0) >= 4,
+        "creates, update and destroy audited: {response}"
+    );
+}
+
+#[ignore]
+#[tokio::test(flavor = "multi_thread")]
+pub async fn mail_rules_tests() {
+    let mut test = TestServerBuilder::new("mail_rules_tests")
+        .await
+        .with_default_listeners()
+        .await
+        .build()
+        .await;
+    let admin = test.create_admin_account("[email protected]").await;
+    test.insert_account(admin);
+    self::test(&mut test).await;
+    if test.is_reset() {
+        test.temp_dir.delete();
+    }
+}

tests/src/system/mod.rs

@@ -14,6 +14,7 @@ pub mod ai_explain;
 pub mod account_lock; // inbuxa: account lock with delegation
 pub mod legal_hold; // inbuxa: legal hold
 pub mod compliance; // inbuxa: the compliance roles
+pub mod mail_rules; // inbuxa: DLP and mail flow rules
 pub mod audit; // inbuxa: the audit log
 pub mod authorization;
 pub mod auto_reload; // inbuxa: registry writes apply at once