huskies: merge 1218 story Remembered/sticky permission approvals so constrained agents stop re-prompting for the same action class

server/src/service/permission_router.rs

@@ -20,7 +20,7 @@
 //! part of the server.
 
 use crate::http::context::{PermissionDecision, PermissionForward};
-use std::collections::{HashMap, VecDeque};
+use std::collections::{HashMap, HashSet, VecDeque};
 use std::sync::Arc;
 use std::sync::Mutex as StdMutex;
 use std::sync::atomic::{AtomicU64, Ordering};
@@ -241,6 +241,57 @@ impl PendingPermReplies {
     }
 }
 
+// ── Remembered permissions ───────────────────────────────────────────────
+
+/// In-memory "don't ask again for this tool + target-pattern" store, scoped
+/// per requesting agent session (story 1218).
+///
+/// Keyed by session id (see `http::mcp::session`) — for a per-story coding
+/// agent this is the story id, stable across a `--resume` of the same story
+/// since the worktree (and its `.mcp.json` header) doesn't change. Rules
+/// remembered here are visible only within the session that recorded them,
+/// so one agent's "don't ask again" never widens what another agent or
+/// story is auto-approved for.
+///
+/// Deliberately **not** persisted to disk: this store lives only as long as
+/// the server process does. Restarting the server clears every remembered
+/// rule (agents will be prompted again once), which is an explicit tradeoff
+/// — durability across restarts would require writing into each worktree's
+/// own `.claude/settings.json`, which adds a second persistence path for a
+/// case (server restarts mid-story) rare enough not to justify the added
+/// complexity.
+pub struct RememberedPermissions {
+    inner: StdMutex<HashMap<String, HashSet<String>>>,
+}
+
+impl RememberedPermissions {
+    /// Create an empty store.
+    pub fn new() -> Arc<Self> {
+        Arc::new(Self {
+            inner: StdMutex::new(HashMap::new()),
+        })
+    }
+
+    /// Record that `rule` is approved for `session_id` going forward.
+    pub fn remember(&self, session_id: &str, rule: &str) {
+        self.inner
+            .lock()
+            .unwrap()
+            .entry(session_id.to_string())
+            .or_default()
+            .insert(rule.to_string());
+    }
+
+    /// `true` if `rule` was previously remembered for `session_id`.
+    pub fn is_remembered(&self, session_id: &str, rule: &str) -> bool {
+        self.inner
+            .lock()
+            .unwrap()
+            .get(session_id)
+            .is_some_and(|rules| rules.contains(rule))
+    }
+}
+
 // ── Tests ─────────────────────────────────────────────────────────────────
 
 #[cfg(test)]
@@ -394,4 +445,36 @@ mod tests {
         let pending = PendingPermReplies::new();
         assert!(pending.resolve_oldest("no-such-room").await.is_none());
     }
+
+    // ── RememberedPermissions ───────────────────────────────────────
+
+    #[test]
+    fn remembered_permissions_starts_empty() {
+        let store = RememberedPermissions::new();
+        assert!(!store.is_remembered("1218", "Bash(git *)"));
+    }
+
+    #[test]
+    fn remembered_permissions_recalls_after_remember() {
+        let store = RememberedPermissions::new();
+        store.remember("1218", "Bash(git *)");
+        assert!(store.is_remembered("1218", "Bash(git *)"));
+    }
+
+    #[test]
+    fn remembered_permissions_scoped_per_session() {
+        let store = RememberedPermissions::new();
+        store.remember("1218", "Bash(git *)");
+        assert!(
+            !store.is_remembered("1216", "Bash(git *)"),
+            "a rule remembered for one story must not apply to another"
+        );
+    }
+
+    #[test]
+    fn remembered_permissions_scoped_per_rule() {
+        let store = RememberedPermissions::new();
+        store.remember("1218", "Bash(git *)");
+        assert!(!store.is_remembered("1218", "Write"));
+    }
 }