feat(rap-protocol): let RAP servers inject system-prompt fragments via their manifest

* `ToolsetManifest` gains an optional `systemPrompt` field (omitted when
  `None`; servers and runtimes that predate it are unaffected).
* When building a session's toolset, the daemon appends each booted
  server's fragment to the session's `extra_system_prompt` under a
  "## Instructions from the `<server>` tool server" header, in config
  order, so every thread of the session sees it. A server that is down
  contributes neither tools nor a fragment.

Author: akainth015

crates/infinity-daemon/src/mcp_proxy.rs

@@ -42,6 +42,7 @@ async fn handle(req: Request<Incoming>, client: McpClient, port: u16) -> Respons
             endpoint: format!("http://127.0.0.1:{port}"),
             tools: descriptor.tools.into_iter().map(Into::into).collect(),
             needs_migration: false,
+            system_prompt: None,
         };
         let manifest =
             serde_json::to_string(&manifest).expect("bug: failed to serialize RAP manifest");

crates/infinity-daemon/src/rap_servers.rs

@@ -500,13 +500,20 @@ impl SessionRapManager {
             }
         }
 
-        // Boot each server once to discover its tools.
+        // Boot each server once to discover its tools and system-prompt fragment.
         let http_client = SimpleHttpClient::new();
         let mut tools: Vec<Rc<dyn Tool<ChannelSender>>> = Vec::new();
         let mut tool_count = 0usize;
+        let mut server_prompts = String::new();
         for server in &servers {
             match server.ensure_up().await {
                 Ok(manifest) => {
+                    if let Some(prompt) = &manifest.system_prompt {
+                        server_prompts.push_str(&format!(
+                            "\n\n## Instructions from the `{}` tool server\n\n{prompt}",
+                            manifest.name
+                        ));
+                    }
                     for def in manifest.tools {
                         tool_count += 1;
                         tools.push(Rc::new(ManagedRapTool {
@@ -537,7 +544,7 @@ impl SessionRapManager {
              Use the `set_title` tool to give the current thread a short, descriptive title. \
              Set it once at the start when the user's intent becomes clear, and update it only \
              when the overall scope of work changes significantly. Do not call it repeatedly \
-             for minor follow-ups within the same task."
+             for minor follow-ups within the same task.{server_prompts}"
         );
 
         let toolset = Rc::new(SessionToolset {

crates/rap-github-event-poller/src/main.rs

@@ -27,6 +27,7 @@ fn build_manifest(endpoint: &str) -> ToolsetManifest {
         description: Some("Subscribe to GitHub repository events via polling (no webhooks required)".to_owned()),
         endpoint: endpoint.to_owned(),
         needs_migration: false,
+        system_prompt: None,
         tools: vec![ToolDef {
             name: "subscribe_github_events".to_owned(),
             description:

crates/rap-protocol/src/lib.rs

@@ -218,6 +218,14 @@ pub struct ToolsetManifest {
     pub tools: Vec<ToolDef>,
     #[serde(default, rename = "needsMigration")]
     pub needs_migration: bool,
+    /// Instructions the runtime appends to the system prompt of every thread
+    /// that can use this server's tools.
+    #[serde(
+        default,
+        rename = "systemPrompt",
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub system_prompt: Option<String>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]

crates/rap-steering-server/src/main.rs

@@ -32,6 +32,7 @@ fn build_manifest(endpoint: &str) -> ToolsetManifest {
         description: Some("Discover and load project steering files (CLAUDE.md, AGENTS.md, .kiro/steering/, etc.)".to_owned()),
         endpoint: endpoint.to_owned(),
         needs_migration: false,
+        system_prompt: None,
         tools: vec![
             ToolDef {
                 name: "list_steering".to_owned(),

crates/sandbox-core/src/server.rs

@@ -2147,6 +2147,7 @@ fn build_manifest(endpoint: &str, needs_migration: bool) -> ToolsetManifest {
         description: Some("Sandboxed code editing and execution tools using jujutsu for filesystem versioning".to_owned()),
         endpoint: endpoint.to_owned(),
         needs_migration,
+        system_prompt: None,
         tools: vec![
             ToolDef {
                 name: "clone_repo".to_owned(),