manager mcp: expose 'remind' tool sharing storage helper with agent surface

TODO.md

@@ -16,7 +16,7 @@
 - ~~Handle text overflow → suggest file_path option for long messages~~ ✓ fixed — Remind dispatch rejects `message.len() > 4096` (when no `file_path` was supplied) with an error pointing at the `file_path` escape hatch.
 - Per-agent reminder limits (burst capacity, rate limiting)
 - ~~**Expose `remind` MCP tool**~~ ✓ fixed — `mcp__hyperhive__remind` now on `AgentServer`; takes `message`, exactly one of `delay_seconds` / `at_unix_timestamp`, optional `file_path`. Manager surface still missing (no `ManagerRequest::Remind` variant) — separate item below.
-- **Manager-side `remind`**: mirror of the agent tool but on `ManagerServer`. Needs `ManagerRequest::Remind` variant in hive-sh4re, dispatch in manager_server.rs, MCP tool wiring.
+- ~~**Manager-side `remind`**~~ ✓ fixed — `ManagerRequest::Remind` variant added, dispatch reuses `agent_server::store_remind` helper (shared across both surfaces), `mcp__hyperhive__remind` now on `ManagerServer` (auto-file lands at `/state/reminders/auto-<ts>.md` — manager's legacy state mount).
 - ~~**File path delivery**~~ ✓ fixed — scheduler now writes the reminder body to the requested `file_path` (mapped from container `/agents/<agent>/state/...` to host `/var/lib/hyperhive/agents/<agent>/state/...`) and delivers a short pointer message in its place. Path-traversal + foreign-agent-state writes are rejected; on rejection or write failure the body falls back to inline delivery with a noted warning. New module `hive-c0re/src/reminder_scheduler.rs` (extracted from main.rs).
 - ~~**Orphan reminders**~~ ✓ fixed — `Broker::deliver_reminder` wraps the inbox INSERT + reminders UPDATE in one sqlite transaction; partial failure can no longer cause duplicate delivery on the next tick.
 - ~~**Unbounded batches**~~ ✓ fixed — scheduler now calls `get_due_reminders(REMINDER_BATCH_LIMIT)` (cap = 100/tick); overflow stays due and gets picked up next cycle.

hive-ag3nt/src/mcp.rs

@@ -665,6 +665,45 @@ impl ManagerServer {
         .await
     }
 
+    #[tool(
+        description = "Schedule a reminder that lands in the manager's own inbox at a future \
+        time (sender will appear as `reminder`). Use for self-paced manager follow-ups: \
+        'recheck pending approval in 10m', 'nudge alice if she hasn't replied by 14:00 \
+        UTC'. Set EXACTLY ONE of `delay_seconds` (fire N seconds from now) or \
+        `at_unix_timestamp` (fire at absolute epoch second). Body soft-caps at 1 KiB \
+        inline — anything larger gets auto-persisted to a file under `/state/reminders/` \
+        (the manager's own state mount) and the inbox message becomes a short pointer. \
+        Pass `file_path` if you want to control the destination yourself."
+    )]
+    async fn remind(&self, Parameters(args): Parameters<RemindArgs>) -> String {
+        let log = format!("{args:?}");
+        run_tool_envelope("remind", log, async move {
+            let timing = match (args.delay_seconds, args.at_unix_timestamp) {
+                (Some(_), Some(_)) => {
+                    return "remind failed: pass exactly one of `delay_seconds` or \
+                            `at_unix_timestamp`, not both"
+                        .to_string();
+                }
+                (None, None) => {
+                    return "remind failed: pass exactly one of `delay_seconds` or \
+                            `at_unix_timestamp`"
+                        .to_string();
+                }
+                (Some(s), None) => hive_sh4re::ReminderTiming::InSeconds { seconds: s },
+                (None, Some(t)) => hive_sh4re::ReminderTiming::At { unix_timestamp: t },
+            };
+            let (resp, retries) = self
+                .dispatch(hive_sh4re::ManagerRequest::Remind {
+                    message: args.message,
+                    timing,
+                    file_path: args.file_path,
+                })
+                .await;
+            annotate_retries(format_ack(resp, "remind", "reminder scheduled".to_string()), retries)
+        })
+        .await
+    }
+
     #[tool(
         description = "Fetch recent journal log lines for a sub-agent container. Useful \
         for diagnosing MCP server registration failures, startup crashes, plugin install \
@@ -753,6 +792,7 @@ pub fn allowed_mcp_tools(flavor: Flavor) -> Vec<String> {
             "request_apply_commit",
             "ask_operator",
             "get_logs",
+            "remind",
         ],
     };
     let mut out: Vec<String> = names

hive-c0re/src/agent_server.rs

@@ -227,30 +227,32 @@ fn handle_remind(
     timing: &hive_sh4re::ReminderTiming,
     file_path: Option<&str>,
 ) -> AgentResponse {
-    let due_at = match resolve_due_at(timing) {
-        Ok(t) => t,
-        Err(e) => {
-            return AgentResponse::Err {
-                message: format!("invalid reminder timing: {e:#}"),
-            };
-        }
-    };
-    let (stored_message, stored_path) = match prepare_remind_storage(agent, message, file_path) {
-        Ok(pair) => pair,
-        Err(e) => return AgentResponse::Err { message: e },
-    };
-    match coord
+    match store_remind(coord, agent, message, timing, file_path) {
+        Ok(()) => AgentResponse::Ok,
+        Err(message) => AgentResponse::Err { message },
+    }
+}
+
+/// Shared remind-storage path used by both the agent and the manager
+/// dispatchers. Validates timing, applies the auto-file overflow
+/// dance (see [`prepare_remind_storage`]), and writes the reminder
+/// row. Returns `Ok(())` on success, or a caller-ready error string
+/// the dispatcher wraps in `*Response::Err`.
+pub(crate) fn store_remind(
+    coord: &Arc<Coordinator>,
+    agent: &str,
+    message: &str,
+    timing: &hive_sh4re::ReminderTiming,
+    file_path: Option<&str>,
+) -> Result<(), String> {
+    let due_at = resolve_due_at(timing).map_err(|e| format!("invalid reminder timing: {e:#}"))?;
+    let (stored_message, stored_path) = prepare_remind_storage(agent, message, file_path)?;
+    let id = coord
         .broker
         .store_reminder(agent, &stored_message, stored_path.as_deref(), due_at)
-    {
-        Ok(id) => {
-            tracing::info!(%id, %agent, %due_at, "reminder scheduled");
-            AgentResponse::Ok
-        }
-        Err(e) => AgentResponse::Err {
-            message: format!("failed to store reminder: {e:#}"),
-        },
-    }
+        .map_err(|e| format!("failed to store reminder: {e:#}"))?;
+    tracing::info!(%id, %agent, %due_at, "reminder scheduled");
+    Ok(())
 }
 
 /// Decide what we actually store in the reminders row, applying the

hive-c0re/src/manager_server.rs

@@ -307,6 +307,20 @@ async fn dispatch(req: &ManagerRequest, coord: &Arc<Coordinator>) -> ManagerResp
                 },
             }
         }
+        ManagerRequest::Remind {
+            message,
+            timing,
+            file_path,
+        } => match crate::agent_server::store_remind(
+            coord,
+            MANAGER_AGENT,
+            message,
+            timing,
+            file_path.as_deref(),
+        ) {
+            Ok(()) => ManagerResponse::Ok,
+            Err(message) => ManagerResponse::Err { message },
+        },
         ManagerRequest::RequestApplyCommit {
             agent,
             commit_ref,

hive-c0re/src/reminder_scheduler.rs

@@ -165,6 +165,20 @@ pub fn write_payload(agent: &str, host_path: &Path, message: &str) -> Result<(),
     Ok(())
 }
 
+/// Container-visible state prefix the caller's `file_path` must live
+/// under. Sub-agents see their state at `/agents/<name>/state/`;
+/// the manager keeps the legacy `/state/` mount (see
+/// `lifecycle::set_nspawn_flags`). Auto-file paths use the same
+/// prefix so the round-trip is symmetric.
+#[must_use]
+pub fn container_state_prefix(agent: &str) -> String {
+    if agent == hive_sh4re::MANAGER_AGENT {
+        "/state/".to_owned()
+    } else {
+        format!("/agents/{agent}/state/")
+    }
+}
+
 /// Map an agent-visible container path to the matching host path,
 /// validating that it lives under the agent's own state subtree, has
 /// a non-empty relative tail, and doesn't try to traverse out via
@@ -172,7 +186,7 @@ pub fn write_payload(agent: &str, host_path: &Path, message: &str) -> Result<(),
 /// reason string on rejection. `pub` so `agent_server::handle_remind`
 /// can reuse it for the at-remind-time auto-file path.
 pub fn resolve_host_path(agent: &str, req_path: &str) -> Result<PathBuf, String> {
-    let prefix = format!("/agents/{agent}/state/");
+    let prefix = container_state_prefix(agent);
     let Some(rel) = req_path.strip_prefix(&prefix) else {
         return Err(format!(
             "must be absolute and under `{prefix}` (got `{req_path}`)"
@@ -230,6 +244,21 @@ mod tests {
         );
     }
 
+    #[test]
+    fn manager_uses_legacy_state_prefix() {
+        // The manager container mounts its state at `/state/` (legacy),
+        // not `/agents/manager/state/`. Same host path; different
+        // container-visible path. resolve_host_path needs to know.
+        assert_eq!(container_state_prefix("manager"), "/state/");
+        let p = resolve_host_path("manager", "/state/reminders/x.md").unwrap();
+        assert_eq!(
+            p,
+            PathBuf::from("/var/lib/hyperhive/agents/manager/state/reminders/x.md")
+        );
+        // And the sub-agent prefix must NOT be accepted for the manager.
+        assert!(resolve_host_path("manager", "/agents/manager/state/x.md").is_err());
+    }
+
     #[test]
     fn prepare_body_passthrough_when_no_file_path() {
         let s = prepare_body("foo", "hello world", None);

hive-sh4re/src/lib.rs

@@ -486,6 +486,17 @@ pub enum ManagerRequest {
         #[serde(default)]
         lines: Option<u32>,
     },
+    /// Mirror of `AgentRequest::Remind` on the manager surface — schedule
+    /// a reminder addressed to the manager itself. Same semantics: body
+    /// soft-caps at 1 KiB, oversize bodies auto-persist to
+    /// `/state/reminders/auto-<ts>.md` (the manager container's own state
+    /// mount) and the inbox sees a pointer.
+    Remind {
+        message: String,
+        timing: ReminderTiming,
+        #[serde(default)]
+        file_path: Option<String>,
+    },
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]