feat(#2): split harness-internal state from agent-visible state

hive-c0re/src/coordinator.rs

@@ -875,13 +875,22 @@ impl Coordinator {
     }
 
     /// Per-agent durable knowledge dir. Bind-mounted RW into the agent
-    /// container at `/state`. Survives destroy/recreate alongside the
-    /// claude dir. Agents are told (via the system prompt) to write
-    /// long-lived notes / scratch state here.
+    /// container at `/agents/{name}/state`. Survives destroy/recreate.
+    /// Agent-visible — claude is told to write long-lived notes here.
     pub fn agent_notes_dir(name: &str) -> PathBuf {
         Self::agent_state_root(name).join("state")
     }
 
+    /// Per-agent harness-internal state dir. Bind-mounted RW into the
+    /// agent container at `/agents/{name}/harness`. Holds sqlite dbs
+    /// and config files owned by the harness (`hyperhive-events.sqlite`,
+    /// `hyperhive-turn-stats.sqlite`, `hyperhive-model`) — kept separate
+    /// from the agent-visible `state/` so claude's "my notes" view is
+    /// uncluttered and the host vacuum has a clean sweep root.
+    pub fn agent_harness_dir(name: &str) -> PathBuf {
+        Self::agent_state_root(name).join("harness")
+    }
+
     /// Authoritative applied config repo. Hive-c0re-only.
     pub fn agent_applied_dir(name: &str) -> PathBuf {
         PathBuf::from(format!("{APPLIED_STATE_ROOT}/{name}"))

hive-c0re/src/events_vacuum.rs

@@ -1,7 +1,8 @@
 //! Host-side vacuum of every per-agent events.sqlite. The harness
-//! writes to `/state/hyperhive-events.sqlite` (bind-mounted from
-//! `/var/lib/hyperhive/agents/<name>/state/`); we open the same file
-//! from the host every hour and delete rows older than `KEEP_SECS`.
+//! writes to `/agents/<name>/harness/hyperhive-events.sqlite`
+//! (bind-mounted from `/var/lib/hyperhive/agents/<name>/harness/`);
+//! we open the same file from the host every hour and delete rows
+//! older than `KEEP_SECS`.
 //! Age-only — no row cap — so a chatty turn doesn't lose history
 //! sooner than a quiet one; disk pressure on a sustained burst is
 //! a cheaper problem than a missing event when the operator is
@@ -41,7 +42,7 @@ pub fn spawn(coord: &Arc<Coordinator>) {
 
 fn sweep_once() {
     for name in Coordinator::kept_state_names() {
-        let path = Coordinator::agent_notes_dir(&name).join("hyperhive-events.sqlite");
+        let path = Coordinator::agent_harness_dir(&name).join("hyperhive-events.sqlite");
         if !path.exists() {
             continue;
         }

hive-c0re/src/lifecycle.rs

@@ -755,12 +755,21 @@ pub fn ensure_claude_dir(claude_dir: &Path) -> Result<()> {
 }
 
 /// Public for the `InitConfig` approval path in `actions.rs` which seeds
-/// dirs without calling the full `spawn`.
+/// dirs without calling the full `spawn`. Also creates the sibling `harness/`
+/// dir so the first harness startup can write its sqlite files immediately.
 pub fn ensure_state_dir(notes_dir: &Path) -> Result<()> {
     if !notes_dir.exists() {
         std::fs::create_dir_all(notes_dir)
             .with_context(|| format!("create {}", notes_dir.display()))?;
     }
+    // Harness dir is a sibling of the agent-visible state dir.
+    if let Some(parent) = notes_dir.parent() {
+        let harness_dir = parent.join("harness");
+        if !harness_dir.exists() {
+            std::fs::create_dir_all(&harness_dir)
+                .with_context(|| format!("create {}", harness_dir.display()))?;
+        }
+    }
     Ok(())
 }
 
@@ -1086,15 +1095,30 @@ fn set_nspawn_flags(
         shared = HOST_SHARED_ROOT,
     );
 
-    // Per-agent state at `/agents/<container>/state`. Skipped for
-    // the manager — the `/agents` bind below already exposes its
-    // own state (along with every sub-agent's).
+    // Per-agent state + harness dirs. Skipped for the manager —
+    // the `/agents` bind below already exposes both (along with
+    // every sub-agent's). For regular agents the harness dir is
+    // the sibling of notes_dir (same parent, "harness" subdir).
     if container != MANAGER_NAME {
         let _ = write!(
             binds,
             " --bind={notes}:/agents/{agent_name}/state",
             notes = notes_dir.display(),
         );
+        // Harness dir: sibling of notes_dir under the agent state root.
+        // systemd-nspawn refuses to start when the bind source is missing;
+        // ensure_state_dir already creates it, but be defensive here.
+        if let Some(parent) = notes_dir.parent() {
+            let harness_dir = parent.join("harness");
+            if !harness_dir.exists() {
+                let _ = std::fs::create_dir_all(&harness_dir);
+            }
+            let _ = write!(
+                binds,
+                " --bind={harness}:/agents/{agent_name}/harness",
+                harness = harness_dir.display(),
+            );
+        }
     }
     if container == MANAGER_NAME {
         // systemd-nspawn refuses to start a container whose bind

hive-c0re/src/meta.rs

@@ -480,10 +480,12 @@ where
               environment.variables = {
                 HIVE_LABEL = name;
                 HYPERHIVE_STATE_DIR = "/agents/${name}/state";
+                HYPERHIVE_HARNESS_DIR = "/agents/${name}/harness";
               };
               systemd.globalEnvironment = {
                 HIVE_LABEL = name;
                 HYPERHIVE_STATE_DIR = "/agents/${name}/state";
+                HYPERHIVE_HARNESS_DIR = "/agents/${name}/harness";
               };
               systemd.services.${service}.environment = parentEnv // toolGroupsEnv // {
                 HIVE_PORT = toString port;
@@ -521,6 +523,7 @@ where
     }
     out.push_str(
         r#"                HYPERHIVE_STATE_DIR = "/agents/${name}/state";
+                HYPERHIVE_HARNESS_DIR = "/agents/${name}/harness";
               };
             }
           ];

hive-c0re/src/migrate.rs

@@ -47,6 +47,13 @@ pub async fn run(coord: &Arc<Coordinator>) -> Result<()> {
     let names = enumerate_agents().await;
     tracing::info!(count = names.len(), "migration: scanning");
 
+    // Phase 0: move harness-owned files out of state/ into harness/.
+    // Idempotent — rename is a no-op if the source doesn't exist and
+    // the destination already does.
+    for name in &names {
+        migrate_harness_files(name);
+    }
+
     // Phase 1 + 2: per-agent applied + proposed.
     for name in &names {
         if let Err(e) = migrate_applied_repo(name).await {
@@ -104,6 +111,35 @@ pub async fn run(coord: &Arc<Coordinator>) -> Result<()> {
     Ok(())
 }
 
+/// Move harness-owned sqlite/config files out of the agent-visible state dir
+/// and into the sibling harness dir. Best-effort: logs warnings but never
+/// fails. Idempotent — each file is only moved if present at the old path
+/// and absent at the new path.
+fn migrate_harness_files(name: &str) {
+    const HARNESS_FILES: &[&str] = &[
+        "hyperhive-events.sqlite",
+        "hyperhive-turn-stats.sqlite",
+        "hyperhive-model",
+    ];
+    let state_dir = Coordinator::agent_notes_dir(name);
+    let harness_dir = Coordinator::agent_harness_dir(name);
+    if let Err(e) = std::fs::create_dir_all(&harness_dir) {
+        tracing::warn!(%name, error = ?e, "migration: create harness dir failed");
+        return;
+    }
+    for file in HARNESS_FILES {
+        let src = state_dir.join(file);
+        let dst = harness_dir.join(file);
+        if !src.exists() || dst.exists() {
+            continue;
+        }
+        match std::fs::rename(&src, &dst) {
+            Ok(()) => tracing::info!(%name, %file, "migration: moved to harness dir"),
+            Err(e) => tracing::warn!(%name, %file, error = ?e, "migration: move to harness dir failed"),
+        }
+    }
+}
+
 async fn enumerate_agents() -> Vec<String> {
     let containers = lifecycle::list().await.unwrap_or_default();
     containers

hive-c0re/src/stats_vacuum.rs

@@ -1,6 +1,6 @@
 //! Host-side vacuum of every per-agent turn-stats.sqlite. The harness
-//! writes to `/state/hyperhive-turn-stats.sqlite` (bind-mounted from
-//! `/var/lib/hyperhive/agents/<name>/state/`); we open the same file
+//! writes to `/agents/<name>/harness/hyperhive-turn-stats.sqlite`
+//! (bind-mounted from `/var/lib/hyperhive/agents/<name>/harness/`); we open the same file
 //! from the host every hour and delete rows older than `KEEP_SECS`.
 //! Mirrors `events_vacuum` in structure — host-side so the harness
 //! can't disable it, age-only so a chatty burst doesn't evict old
@@ -40,7 +40,7 @@ pub fn spawn(coord: &Arc<Coordinator>) {
 fn sweep_once() {
     for name in Coordinator::kept_state_names() {
         let path =
-            Coordinator::agent_notes_dir(&name).join("hyperhive-turn-stats.sqlite");
+            Coordinator::agent_harness_dir(&name).join("hyperhive-turn-stats.sqlite");
         if !path.exists() {
             continue;
         }