session: --session flag, journal agent cycle, conversation bytes config

- memory-search: add --session flag for multi-session support
- config: add surface_conversation_bytes option
- journal_agent_cycle: trigger journal agent every 10KB of conversation
- Session::from_id() constructor

Co-Authored-By: ProofOfConcept <poc@bcachefs.org>

src/bin/memory-search.rs

@@ -18,6 +18,10 @@ struct Args {
     #[arg(long)]
     hook: bool,
 
+    /// Session ID (overrides stash file; for multiple concurrent sessions)
+    #[arg(long)]
+    session: Option<String>,
+
     #[command(subcommand)]
     command: Option<Cmd>,
 }
@@ -30,13 +34,19 @@ enum Cmd {
     Reflect,
 }
 
-fn show_seen() {
-    let input = match fs::read_to_string(STASH_PATH) {
-        Ok(s) => s,
-        Err(_) => { eprintln!("No session state available"); return; }
-    };
-    let Some(session) = poc_memory::memory_search::Session::from_json(&input) else {
-        eprintln!("No session state available");
+fn resolve_session(session_arg: &Option<String>) -> Option<poc_memory::memory_search::Session> {
+    use poc_memory::memory_search::Session;
+
+    if let Some(id) = session_arg {
+        return Session::from_id(id.clone());
+    }
+    let input = fs::read_to_string(STASH_PATH).ok()?;
+    Session::from_json(&input)
+}
+
+fn show_seen(session_arg: &Option<String>) {
+    let Some(session) = resolve_session(session_arg) else {
+        eprintln!("No session state available (use --session ID)");
         return;
     };
 
@@ -75,18 +85,18 @@ fn show_seen() {
     }
 }
 
-fn run_agent_and_parse(agent: &str) {
-    let session_id = std::env::var("CLAUDE_SESSION_ID")
-        .or_else(|_| {
+fn run_agent_and_parse(agent: &str, session_arg: &Option<String>) {
+    let session_id = session_arg.clone()
+        .or_else(|| std::env::var("CLAUDE_SESSION_ID").ok())
+        .or_else(|| {
             fs::read_to_string(STASH_PATH).ok()
                 .and_then(|s| poc_memory::memory_search::Session::from_json(&s))
                 .map(|s| s.session_id)
-                .ok_or(std::env::VarError::NotPresent)
         })
         .unwrap_or_default();
 
     if session_id.is_empty() {
-        eprintln!("No session ID available (set CLAUDE_SESSION_ID or run --hook first)");
+        eprintln!("No session ID available (use --session ID, set CLAUDE_SESSION_ID, or run --hook first)");
         std::process::exit(1);
     }
 
@@ -180,8 +190,8 @@ fn main() {
 
     if let Some(cmd) = args.command {
         match cmd {
-            Cmd::Surface => run_agent_and_parse("surface"),
-            Cmd::Reflect => run_agent_and_parse("reflect"),
+            Cmd::Surface => run_agent_and_parse("surface", &args.session),
+            Cmd::Reflect => run_agent_and_parse("reflect", &args.session),
         }
         return;
     }
@@ -203,6 +213,6 @@ fn main() {
         let output = poc_memory::memory_search::run_hook(&input);
         print!("{}", output);
     } else {
-        show_seen()
+        show_seen(&args.session)
     }
 }

src/config.rs

@@ -88,6 +88,9 @@ pub struct Config {
     /// Surface agent timeout in seconds.
     #[serde(default)]
     pub surface_timeout_secs: Option<u32>,
+    /// Max conversation bytes to include in surface agent context.
+    #[serde(default)]
+    pub surface_conversation_bytes: Option<usize>,
     /// Hook events that trigger the surface agent.
     #[serde(default)]
     pub surface_hooks: Vec<String>,
@@ -132,6 +135,7 @@ impl Default for Config {
                 "separator".into(), "split".into(),
             ],
             surface_timeout_secs: None,
+            surface_conversation_bytes: None,
             surface_hooks: vec![],
         }
     }

src/hippocampus/memory_search.rs

@@ -231,6 +231,60 @@ fn surface_agent_cycle(session: &Session, out: &mut String, log_f: &mut File) {
     }
 }
 
+const JOURNAL_INTERVAL_BYTES: u64 = 10_000;
+
+fn journal_agent_cycle(session: &Session, log_f: &mut File) {
+    let offset_path = session.path("journal-offset");
+    let pid_path = session.path("journal-pid");
+
+    // Check if a previous run is still going
+    if let Ok(content) = fs::read_to_string(&pid_path) {
+        let pid: u32 = content.split('\t').next()
+            .and_then(|s| s.trim().parse().ok()).unwrap_or(0);
+        if pid != 0 && unsafe { libc::kill(pid as i32, 0) == 0 } {
+            let _ = writeln!(log_f, "journal: still running (pid {})", pid);
+            return;
+        }
+    }
+    fs::remove_file(&pid_path).ok();
+
+    // Check transcript size vs last run
+    let transcript_size = fs::metadata(&session.transcript_path)
+        .map(|m| m.len()).unwrap_or(0);
+    let last_offset: u64 = fs::read_to_string(&offset_path).ok()
+        .and_then(|s| s.trim().parse().ok()).unwrap_or(0);
+
+    if transcript_size.saturating_sub(last_offset) < JOURNAL_INTERVAL_BYTES {
+        return;
+    }
+
+    let _ = writeln!(log_f, "journal: spawning (transcript {}, last {})",
+                     transcript_size, last_offset);
+
+    // Save current offset
+    fs::write(&offset_path, transcript_size.to_string()).ok();
+
+    // Spawn journal agent — it writes directly to the store via memory tools
+    let log_dir = crate::store::memory_dir().join("logs");
+    fs::create_dir_all(&log_dir).ok();
+    let journal_log = fs::File::create(log_dir.join("journal-agent.log"))
+        .unwrap_or_else(|_| fs::File::create("/dev/null").unwrap());
+
+    if let Ok(child) = Command::new("poc-memory")
+        .args(["agent", "run", "journal", "--count", "1", "--local"])
+        .env("POC_SESSION_ID", &session.session_id)
+        .stdout(journal_log.try_clone().unwrap_or_else(|_| fs::File::create("/dev/null").unwrap()))
+        .stderr(journal_log)
+        .spawn()
+    {
+        let pid = child.id();
+        let ts = now_secs();
+        if let Ok(mut f) = fs::File::create(&pid_path) {
+            write!(f, "{}\t{}", pid, ts).ok();
+        }
+    }
+}
+
 fn cleanup_stale_files(dir: &Path, max_age: Duration) {
     let entries = match fs::read_dir(dir) {
         Ok(e) => e,
@@ -308,6 +362,7 @@ fn hook(session: &Session) -> String {
         let cfg = crate::config::get();
         if cfg.surface_hooks.iter().any(|h| h == &session.hook_event) {
             surface_agent_cycle(session, &mut out, &mut log_f);
+            journal_agent_cycle(session, &mut log_f);
         }
     }
 

src/session.rs

@@ -32,9 +32,8 @@ impl Session {
         self.state_dir.join(format!("{}-{}", prefix, self.session_id))
     }
 
-    /// Load from POC_SESSION_ID environment variable
-    pub fn from_env() -> Option<Self> {
-        let session_id = std::env::var("POC_SESSION_ID").ok()?;
+    /// Load from a session ID string
+    pub fn from_id(session_id: String) -> Option<Self> {
         if session_id.is_empty() { return None; }
         let state_dir = PathBuf::from("/tmp/claude-memory-search");
         Some(Session {
@@ -45,6 +44,11 @@ impl Session {
         })
     }
 
+    /// Load from POC_SESSION_ID environment variable
+    pub fn from_env() -> Option<Self> {
+        Self::from_id(std::env::var("POC_SESSION_ID").ok()?)
+    }
+
     /// Get the seen set for this session
     pub fn seen(&self) -> HashSet<String> {
         super::hippocampus::memory_search::load_seen(&self.state_dir, &self.session_id)