feat: add agent roles to collab tools (#9275)

Add `agent_type` parameter to the collab tool `spawn_agent` that
contains a preset to apply on the config when spawning this agent

codex-rs/core/src/agent/mod.rs

@@ -1,6 +1,8 @@
 pub(crate) mod control;
+pub(crate) mod role;
 pub(crate) mod status;
 
 pub(crate) use codex_protocol::protocol::AgentStatus;
 pub(crate) use control::AgentControl;
+pub(crate) use role::AgentRole;
 pub(crate) use status::agent_status_from_event;

codex-rs/core/src/agent/role.rs

@@ -0,0 +1,85 @@
+use crate::config::Config;
+use crate::protocol::SandboxPolicy;
+use serde::Deserialize;
+use serde::Serialize;
+
+/// Base instructions for the orchestrator role.
+const ORCHESTRATOR_PROMPT: &str = include_str!("../../templates/agents/orchestrator.md");
+/// Base instructions for the worker role.
+const WORKER_PROMPT: &str = include_str!("../../gpt-5.2-codex_prompt.md");
+/// Default worker model override used by the worker role.
+const WORKER_MODEL: &str = "gpt-5.2-codex";
+
+/// Enumerated list of all supported agent roles.
+const ALL_ROLES: [AgentRole; 3] = [
+    AgentRole::Default,
+    AgentRole::Orchestrator,
+    AgentRole::Worker,
+];
+
+/// Hard-coded agent role selection used when spawning sub-agents.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum AgentRole {
+    /// Inherit the parent agent's configuration unchanged.
+    Default,
+    /// Coordination-only agent that delegates to workers.
+    Orchestrator,
+    /// Task-executing agent with a fixed model override.
+    Worker,
+}
+
+/// Immutable profile data that drives per-agent configuration overrides.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub struct AgentProfile {
+    /// Optional base instructions override.
+    pub base_instructions: Option<&'static str>,
+    /// Optional model override.
+    pub model: Option<&'static str>,
+    /// Whether to force a read-only sandbox policy.
+    pub read_only: bool,
+}
+
+impl AgentRole {
+    /// Returns the string values used by JSON schema enums.
+    pub fn enum_values() -> Vec<String> {
+        ALL_ROLES
+            .iter()
+            .filter_map(|role| serde_json::to_string(role).ok())
+            .collect()
+    }
+
+    /// Returns the hard-coded profile for this role.
+    pub fn profile(self) -> AgentProfile {
+        match self {
+            AgentRole::Default => AgentProfile::default(),
+            AgentRole::Orchestrator => AgentProfile {
+                base_instructions: Some(ORCHESTRATOR_PROMPT),
+                ..Default::default()
+            },
+            AgentRole::Worker => AgentProfile {
+                base_instructions: Some(WORKER_PROMPT),
+                model: Some(WORKER_MODEL),
+                ..Default::default()
+            },
+        }
+    }
+
+    /// Applies this role's profile onto the provided config.
+    pub fn apply_to_config(self, config: &mut Config) -> Result<(), String> {
+        let profile = self.profile();
+        if let Some(base_instructions) = profile.base_instructions {
+            config.base_instructions = Some(base_instructions.to_string());
+        }
+        if let Some(model) = profile.model {
+            config.model = Some(model.to_string());
+        }
+        if profile.read_only {
+            config
+                .sandbox_policy
+                .set(SandboxPolicy::new_read_only_policy())
+                .map_err(|err| format!("sandbox_policy is invalid: {err}"))?;
+        }
+        Ok(())
+    }
+}

codex-rs/core/src/codex.rs

@@ -541,24 +541,12 @@ impl Session {
             web_search_mode: per_turn_config.web_search_mode,
         });
 
-        let base_instructions = if per_turn_config.features.enabled(Feature::Collab) {
-            const COLLAB_INSTRUCTIONS: &str =
-                include_str!("../templates/collab/experimental_prompt.md");
-            let base = session_configuration
-                .base_instructions
-                .as_deref()
-                .unwrap_or(model_info.base_instructions.as_str());
-            Some(format!("{base}\n\n{COLLAB_INSTRUCTIONS}"))
-        } else {
-            session_configuration.base_instructions.clone()
-        };
-
         TurnContext {
             sub_id,
             client,
             cwd: session_configuration.cwd.clone(),
             developer_instructions: session_configuration.developer_instructions.clone(),
-            base_instructions,
+            base_instructions: session_configuration.base_instructions.clone(),
             compact_prompt: session_configuration.compact_prompt.clone(),
             user_instructions: session_configuration.user_instructions.clone(),
             approval_policy: session_configuration.approval_policy.value(),

codex-rs/core/src/tools/handlers/collab.rs

@@ -76,11 +76,13 @@ impl ToolHandler for CollabHandler {
 
 mod spawn {
     use super::*;
+    use crate::agent::AgentRole;
     use std::sync::Arc;
 
     #[derive(Debug, Deserialize)]
     struct SpawnAgentArgs {
         message: String,
+        agent_type: Option<AgentRole>,
     }
 
     #[derive(Debug, Serialize)]
@@ -95,6 +97,7 @@ mod spawn {
         arguments: String,
     ) -> Result<ToolOutput, FunctionCallError> {
         let args: SpawnAgentArgs = parse_arguments(&arguments)?;
+        let agent_role = args.agent_type.unwrap_or(AgentRole::Default);
         let prompt = args.message;
         if prompt.trim().is_empty() {
             return Err(FunctionCallError::RespondToModel(
@@ -112,7 +115,10 @@ mod spawn {
                 .into(),
             )
             .await;
-        let config = build_agent_spawn_config(turn.as_ref())?;
+        let mut config = build_agent_spawn_config(turn.as_ref())?;
+        agent_role
+            .apply_to_config(&mut config)
+            .map_err(FunctionCallError::RespondToModel)?;
         let result = session
             .services
             .agent_control

codex-rs/core/src/tools/spec.rs

@@ -1,3 +1,4 @@
+use crate::agent::AgentRole;
 use crate::client_common::tools::ResponsesApiTool;
 use crate::client_common::tools::ToolSpec;
 use crate::features::Feature;
@@ -441,6 +442,15 @@ fn create_spawn_agent_tool() -> ToolSpec {
             description: Some("Initial message to send to the new agent.".to_string()),
         },
     );
+    properties.insert(
+        "agent_type".to_string(),
+        JsonSchema::String {
+            description: Some(format!(
+                "Optional agent type to spawn ({}).",
+                AgentRole::enum_values().join(", ")
+            )),
+        },
+    );
 
     ToolSpec::Function(ResponsesApiTool {
         name: "spawn_agent".to_string(),