feat(acp): session rotation on context window exhaustion

crates/sprout-acp/src/config.rs

@@ -185,6 +185,12 @@ pub struct CliArgs {
           value_parser = clap::value_parser!(u32).range(0..=100))]
     pub context_message_limit: u32,
 
+    /// Maximum turns per session before proactive rotation. 0 = disabled
+    /// (rotate only on MaxTokens / MaxTurnRequests).
+    #[arg(long, env = "SPROUT_ACP_MAX_TURNS_PER_SESSION", default_value_t = 0,
+          value_parser = clap::value_parser!(u32))]
+    pub max_turns_per_session: u32,
+
     /// Disable automatic presence (online/offline) status.
     #[arg(long, env = "SPROUT_ACP_NO_PRESENCE")]
     pub no_presence: bool,
@@ -234,6 +240,8 @@ pub struct Config {
     pub no_mention_filter: bool,
     pub config_path: PathBuf,
     pub context_message_limit: u32,
+    /// Maximum turns per session before proactive rotation. 0 = disabled.
+    pub max_turns_per_session: u32,
     pub presence_enabled: bool,
     pub typing_enabled: bool,
     /// Desired LLM model ID. Applied after every `session_new_full()`.
@@ -373,6 +381,7 @@ impl Config {
             no_mention_filter: args.no_mention_filter,
             config_path: args.config,
             context_message_limit: args.context_message_limit,
+            max_turns_per_session: args.max_turns_per_session,
             presence_enabled: !args.no_presence,
             typing_enabled: !args.no_typing,
             model: args.model,
@@ -382,7 +391,7 @@ impl Config {
     /// Human-readable summary (no secrets).
     pub fn summary(&self) -> String {
         format!(
-            "relay={} pubkey={} agent_cmd={} {} mcp_cmd={} timeout={}s agents={} heartbeat={}s subscribe={:?} dedup={:?} ignore_self={} context_limit={} presence={} typing={} model={}",
+            "relay={} pubkey={} agent_cmd={} {} mcp_cmd={} timeout={}s agents={} heartbeat={}s subscribe={:?} dedup={:?} ignore_self={} context_limit={} max_turns_per_session={} presence={} typing={} model={}",
             self.relay_url,
             self.keys.public_key().to_hex(),
             self.agent_command,
@@ -395,6 +404,7 @@ impl Config {
             self.dedup_mode,
             self.ignore_self,
             self.context_message_limit,
+            self.max_turns_per_session,
             self.presence_enabled,
             self.typing_enabled,
             self.model.as_deref().unwrap_or("(agent default)"),
@@ -692,6 +702,7 @@ mod tests {
             no_mention_filter: false,
             config_path: PathBuf::from("./sprout-acp.toml"),
             context_message_limit: 12,
+            max_turns_per_session: 0,
             presence_enabled: true,
             typing_enabled: true,
             model: None,

crates/sprout-acp/src/main.rs

@@ -18,7 +18,9 @@ use config::{Config, DedupMode, ModelsArgs, SubscribeMode};
 use filter::SubscriptionRule;
 use futures_util::FutureExt;
 use nostr::ToBech32;
-use pool::{AgentPool, OwnedAgent, PromptContext, PromptOutcome, PromptResult, PromptSource};
+use pool::{
+    AgentPool, OwnedAgent, PromptContext, PromptOutcome, PromptResult, PromptSource, SessionState,
+};
 use queue::{EventQueue, QueuedEvent};
 use relay::HarnessRelay;
 use sprout_core::kind::{
@@ -82,8 +84,7 @@ async fn main() -> Result<()> {
         agents.push(OwnedAgent {
             index: i,
             acp,
-            sessions: HashMap::new(),
-            heartbeat_session: None,
+            state: SessionState::default(),
             model_capabilities: None,
             desired_model: config.model.clone(),
         });
@@ -228,6 +229,7 @@ async fn main() -> Result<()> {
         rest_client: relay.rest_client(),
         channel_info: channel_info_map,
         context_message_limit: config.context_message_limit,
+        max_turns_per_session: config.max_turns_per_session,
     });
 
     // ── Step 6: Heartbeat timer ───────────────────────────────────────────────
@@ -808,11 +810,8 @@ async fn handle_prompt_result(
     // Strip sessions for channels the agent was removed from while this
     // agent was checked out. This covers the gap where invalidate_channel_sessions
     // only touches idle agents.
-    if !removed_channels.is_empty() {
-        result
-            .agent
-            .sessions
-            .retain(|ch, _| !removed_channels.contains(ch));
+    for ch in removed_channels {
+        result.agent.state.invalidate_channel(ch);
     }
 
     let outcome_label = match &result.outcome {
@@ -899,8 +898,7 @@ async fn recover_panicked_agent(
             pool.agents_mut()[i] = Some(OwnedAgent {
                 index: i,
                 acp,
-                sessions: HashMap::new(),
-                heartbeat_session: None,
+                state: SessionState::default(),
                 model_capabilities: None,
                 desired_model: config.model.clone(),
             });
@@ -1011,8 +1009,7 @@ async fn respawn_agent_into(old_agent: OwnedAgent, config: &Config) -> Result<Ow
     Ok(OwnedAgent {
         index,
         acp,
-        sessions: HashMap::new(),
-        heartbeat_session: None,
+        state: SessionState::default(),
         model_capabilities: None,
         desired_model: config.model.clone(),
     })