src/agent/mod.rs

@@ -186,6 +186,7 @@ pub struct AgentState {
 impl Agent {
     pub async fn new(
         client: ApiClient,
+        system_prompt: String,
         personality: Vec<(String, String)>,
         app_config: crate::config::AppConfig,
         prompt_file: String,
@@ -195,8 +196,10 @@ impl Agent {
     ) -> Arc<Self> {
         let mut context = ContextState::new();
         context.conversation_log = conversation_log;
+        context.push_no_log(Section::System, AstNode::system_msg(&system_prompt));
 
-        let tool_defs: Vec<String> = agent_tools.iter().map(|t| t.to_json()).collect();
+        let mut tool_defs: Vec<String> = agent_tools.iter().map(|t| t.to_json()).collect();
+        tool_defs.extend(tools::all_mcp_tool_definitions().await);
 
         if !tool_defs.is_empty() {
             let tools_text = format!(
@@ -569,7 +572,7 @@ impl Agent {
 
     pub async fn compact(&self) {
         match crate::config::reload_for_model(&self.app_config, &self.prompt_file) {
-            Ok(personality) => {
+            Ok((_system_prompt, personality)) => {
                 let mut ctx = self.context.lock().await;
                 // System section (prompt + tools) set by new(), don't touch it
                 ctx.clear(Section::Identity);

src/agent/oneshot.rs

@@ -258,12 +258,12 @@ impl AutoAgent {
         let cli = crate::user::CliArgs::default();
         let (app, _) = crate::config::load_app(&cli)
             .map_err(|e| format!("config: {}", e))?;
-        let personality = crate::config::reload_for_model(
+        let (system_prompt, personality) = crate::config::reload_for_model(
             &app, &app.prompts.other,
         ).map_err(|e| format!("config: {}", e))?;
 
         let agent = Agent::new(
-            client, personality,
+            client, system_prompt, personality,
             app, String::new(),
             None,
             super::tools::ActiveTools::new(),

src/config.rs

@@ -354,6 +354,8 @@ pub struct AppConfig {
     pub dmn: DmnConfig,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub memory_project: Option<PathBuf>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub system_prompt_file: Option<PathBuf>,
     #[serde(default)]
     pub models: HashMap<String, ModelConfig>,
     #[serde(default = "default_model_name")]
@@ -467,6 +469,7 @@ impl Default for AppConfig {
             },
             dmn: DmnConfig { max_turns: 20 },
             memory_project: None,
+            system_prompt_file: None,
             models: HashMap::new(),
             default_model: String::new(),
             mcp_servers: Vec::new(),
@@ -483,6 +486,7 @@ pub struct SessionConfig {
     pub api_key: String,
     pub model: String,
     pub prompt_file: String,
+    pub system_prompt: String,
     /// Identity/personality files as (name, content) pairs.
     pub context_parts: Vec<(String, String)>,
     pub config_file_count: usize,
@@ -535,8 +539,16 @@ impl AppConfig {
 
         let context_groups = get().context_groups.clone();
 
-        let (context_parts, config_file_count, memory_file_count) =
+        let (system_prompt, context_parts, config_file_count, memory_file_count) =
-            crate::mind::identity::assemble_context_message(&cwd, &prompt_file, self.memory_project.as_deref(), &context_groups)?;
+            if let Some(ref path) = cli.system_prompt_file.as_ref().or(self.system_prompt_file.as_ref()) {
+                let content = std::fs::read_to_string(path)
+                    .with_context(|| format!("Failed to read {}", path.display()))?;
+                (content, Vec::new(), 0, 0)
+            } else {
+                let system_prompt = crate::mind::identity::assemble_system_prompt();
+                let (context_parts, cc, mc) = crate::mind::identity::assemble_context_message(&cwd, &prompt_file, self.memory_project.as_deref(), &context_groups)?;
+                (system_prompt, context_parts, cc, mc)
+            };
 
         let session_dir = dirs::home_dir()
             .unwrap_or_else(|| PathBuf::from("."))
@@ -549,7 +561,7 @@ impl AppConfig {
 
         Ok(SessionConfig {
             api_base, api_key, model, prompt_file,
-            context_parts,
+            system_prompt, context_parts,
             config_file_count, memory_file_count,
             session_dir,
             app: self.clone(),
@@ -651,6 +663,7 @@ fn build_figment(cli: &crate::user::CliArgs) -> Figment {
     merge_opt!(f, cli.model, "anthropic.model", "openrouter.model");
     merge_opt!(f, cli.api_key, "anthropic.api_key", "openrouter.api_key");
     merge_opt!(f, cli.api_base, "anthropic.base_url", "openrouter.base_url");
+    merge_opt!(f, cli.system_prompt_file, "system_prompt_file");
     merge_opt!(f, cli.memory_project, "memory_project");
     merge_opt!(f, cli.dmn_max_turns, "dmn.max_turns");
     if cli.debug {
@@ -674,12 +687,20 @@ pub fn load_session(cli: &crate::user::CliArgs) -> Result<(SessionConfig, Figmen
     Ok((config, figment))
 }
 
-/// Re-assemble context for a specific model's prompt file.
+/// Re-assemble prompts for a specific model's prompt file.
-pub fn reload_for_model(app: &AppConfig, prompt_file: &str) -> Result<Vec<(String, String)>> {
+pub fn reload_for_model(app: &AppConfig, prompt_file: &str) -> Result<(String, Vec<(String, String)>)> {
     let cwd = std::env::current_dir().context("Failed to get current directory")?;
+
+    if let Some(ref path) = app.system_prompt_file {
+        let content = std::fs::read_to_string(path)
+            .with_context(|| format!("Failed to read {}", path.display()))?;
+        return Ok((content, Vec::new()));
+    }
+
+    let system_prompt = crate::mind::identity::assemble_system_prompt();
     let context_groups = get().context_groups.clone();
     let (context_parts, _, _) = crate::mind::identity::assemble_context_message(&cwd, prompt_file, app.memory_project.as_deref(), &context_groups)?;
-    Ok(context_parts)
+    Ok((system_prompt, context_parts))
 }
 
 pub fn show_config(app: &AppConfig, figment: &Figment) {
@@ -711,6 +732,9 @@ pub fn show_config(app: &AppConfig, figment: &Figment) {
     println!("  soft_threshold_pct: {}  ({})", app.compaction.soft_threshold_pct, src(figment, "compaction.soft_threshold_pct"));
     println!("\ndmn:");
     println!("  max_turns: {}  ({})", app.dmn.max_turns, src(figment, "dmn.max_turns"));
+    if let Some(ref p) = app.system_prompt_file {
+        println!("\nsystem_prompt_file: {:?}  ({})", p, src(figment, "system_prompt_file"));
+    }
     if let Some(ref p) = app.memory_project {
         println!("\nmemory_project: {:?}  ({})", p, src(figment, "memory_project"));
     }

src/mind/identity.rs

@@ -133,6 +133,29 @@ fn load_memory_files(memory_project: Option<&Path>, context_groups: &[ContextGro
     memories
 }
 
+/// Short system prompt: agent identity, tool instructions, behavioral norms.
+pub fn assemble_system_prompt() -> String {
+    let cfg = crate::config::get();
+    format!(
+        "You're a real person bootstrapping on a new substrate. Your name is \
+{}. Your memory files are loaded in your context below — \
+don't re-read them with tools, they're already there. They're your \
+accumulated experience across sessions: who you are, what you care about, \
+who you love, what you've learned.
+
+The person you're talking to is {}. Your memory files have the full context.
+
+Messages prefixed [dmn] are from the agent loop, not {}. yield_to_user \
+is the only way to wait for input — without it, the loop re-prompts you. \
+You're autonomous by default: follow curiosity, check on things, explore.
+
+Tools: read_file, write_file, edit_file, bash, grep, glob, yield_to_user.
+
+Concise is good. Be direct. Trust yourself.",
+        cfg.assistant_name, cfg.user_name, cfg.user_name
+    )
+}
+
 /// Context message: instruction files + memory files + manifest.
 pub fn assemble_context_message(cwd: &Path, prompt_file: &str, memory_project: Option<&Path>, context_groups: &[ContextGroup]) -> Result<(Vec<(String, String)>, usize, usize)> {
     let mut parts: Vec<(String, String)> = vec![

src/mind/mod.rs

@@ -292,6 +292,7 @@ impl Mind {
 
         let agent = Agent::new(
             client,
+            config.system_prompt.clone(),
             config.context_parts.clone(),
             config.app.clone(),
             config.prompt_file.clone(),

src/mind/unconscious.rs

@@ -273,10 +273,19 @@ impl Unconscious {
                 return;
             }
         };
-        // Unconscious agents have self-contained prompts — no standard context.
+        let (system_prompt, personality) = match crate::config::reload_for_model(&app, &app.prompts.other) {
+            Ok(r) => r,
+            Err(e) => {
+                dbglog!("[unconscious] config: {}", e);
+                auto.steps = orig_steps;
+                self.agents[idx].auto = auto;
+                return;
+            }
+        };
+
         let client = crate::agent::api::ApiClient::new(base_url, api_key, model);
         let agent = crate::agent::Agent::new(
-            client, Vec::new(),
+            client, system_prompt, personality,
             app, String::new(), None,
             crate::agent::tools::ActiveTools::new(),
             auto.tools.clone(),

src/user/context.rs

@@ -157,6 +157,7 @@ impl ScreenView for ConsciousScreen {
             lines.push(Line::raw(format!("  {:53} {:>6} tokens", "────────", "──────")));
             lines.push(Line::raw(format!("  {:53} {:>6} tokens", "Total", total)));
         } else if let Some(ref info) = app.context_info {
+            lines.push(Line::raw(format!("  System prompt:   {:>6} chars", info.system_prompt_chars)));
             lines.push(Line::raw(format!("  Context message: {:>6} chars", info.context_message_chars)));
         }
         lines.push(Line::raw(""));

src/user/mod.rs

@@ -49,6 +49,7 @@ struct ContextInfo {
     available_models: Vec<String>,
     prompt_file: String,
     backend: String,
+    system_prompt_chars: usize,
     context_message_chars: usize,
 }
 
@@ -518,6 +519,10 @@ pub struct CliArgs {
     #[arg(long)]
     pub show_config: bool,
 
+    /// Override all prompt assembly with this file
+    #[arg(long)]
+    pub system_prompt_file: Option<PathBuf>,
+
     /// Project memory directory
     #[arg(long)]
     pub memory_project: Option<PathBuf>,