Disallow subagents with no extensions (#5825)

crates/goose/src/agents/agent.rs

@@ -640,6 +640,28 @@ impl Agent {
         Ok(())
     }
 
+    pub async fn subagents_enabled(&self) -> bool {
+        let config = crate::config::Config::global();
+        let is_autonomous = config.get_goose_mode().unwrap_or(GooseMode::Auto) == GooseMode::Auto;
+        if !is_autonomous {
+            return false;
+        }
+        if self
+            .provider()
+            .await
+            .map(|provider| provider.get_active_model_name().starts_with("gemini"))
+            .unwrap_or(false)
+        {
+            return false;
+        }
+        !self
+            .extension_manager
+            .list_extensions()
+            .await
+            .map(|ext| ext.is_empty())
+            .unwrap_or(true)
+    }
+
     pub async fn list_tools(&self, extension_name: Option<String>) -> Vec<Tool> {
         let mut prefixed_tools = self
             .extension_manager
@@ -647,8 +669,9 @@ impl Agent {
             .await
             .unwrap_or_default();
 
+        let subagents_enabled = self.subagents_enabled().await;
         if extension_name.is_none() || extension_name.as_deref() == Some("platform") {
-            prefixed_tools.extend([platform_tools::manage_schedule_tool()]);
+            prefixed_tools.push(platform_tools::manage_schedule_tool());
         }
 
         if extension_name.is_none() {
@@ -656,10 +679,11 @@ impl Agent {
                 prefixed_tools.push(final_output_tool.tool());
             }
 
-            // Add the unified subagent tool
-            let sub_recipes = self.sub_recipes.lock().await;
-            let sub_recipes_vec: Vec<_> = sub_recipes.values().cloned().collect();
-            prefixed_tools.push(create_subagent_tool(&sub_recipes_vec));
+            if subagents_enabled {
+                let sub_recipes = self.sub_recipes.lock().await;
+                let sub_recipes_vec: Vec<_> = sub_recipes.values().cloned().collect();
+                prefixed_tools.push(create_subagent_tool(&sub_recipes_vec));
+            }
         }
 
         prefixed_tools
@@ -1374,7 +1398,7 @@ impl Agent {
 
         let prompt_manager = self.prompt_manager.lock().await;
         let system_prompt = prompt_manager
-            .builder(model_name)
+            .builder()
             .with_extensions(extensions_info.into_iter())
             .with_frontend_instructions(self.frontend_instructions.lock().await.clone())
             .with_extension_and_tool_counts(extension_count, tool_count)
@@ -1594,7 +1618,7 @@ mod tests {
         );
 
         let prompt_manager = agent.prompt_manager.lock().await;
-        let system_prompt = prompt_manager.builder("gpt-4o").build();
+        let system_prompt = prompt_manager.builder().build();
 
         let final_output_tool_ref = agent.final_output_tool.lock().await;
         let final_output_tool_system_prompt =

crates/goose/src/agents/prompt_manager.rs

@@ -7,7 +7,6 @@ use std::collections::HashMap;
 
 use crate::agents::extension::ExtensionInfo;
 use crate::agents::router_tools::llm_search_tool_prompt;
-use crate::agents::subagent_tool::should_enable_subagents;
 use crate::hints::load_hints::{load_hint_files, AGENTS_MD_FILENAME, GOOSE_HINTS_FILENAME};
 use crate::{
     config::{Config, GooseMode},
@@ -47,13 +46,13 @@ struct SystemPromptContext {
 }
 
 pub struct SystemPromptBuilder<'a, M> {
-    model_name: String,
     manager: &'a M,
 
     extensions_info: Vec<ExtensionInfo>,
     frontend_instructions: Option<String>,
     extension_tool_count: Option<(usize, usize)>,
     router_enabled: bool,
+    subagents_enabled: bool,
     hints: Option<String>,
 }
 
@@ -116,6 +115,11 @@ impl<'a> SystemPromptBuilder<'a, PromptManager> {
         self
     }
 
+    pub fn with_enable_subagents(mut self, subagents_enabled: bool) -> Self {
+        self.subagents_enabled = subagents_enabled;
+        self
+    }
+
     pub fn build(self) -> String {
         let mut extensions_info = self.extensions_info;
 
@@ -152,7 +156,7 @@ impl<'a> SystemPromptBuilder<'a, PromptManager> {
             extension_tool_limits,
             goose_mode,
             is_autonomous: goose_mode == GooseMode::Auto,
-            enable_subagents: should_enable_subagents(self.model_name.as_str()),
+            enable_subagents: self.subagents_enabled,
             max_extensions: MAX_EXTENSIONS,
             max_tools: MAX_TOOLS,
         };
@@ -228,15 +232,15 @@ impl PromptManager {
         self.system_prompt_override = Some(template);
     }
 
-    pub fn builder<'a>(&'a self, model_name: &str) -> SystemPromptBuilder<'a, Self> {
+    pub fn builder<'a>(&'a self) -> SystemPromptBuilder<'a, Self> {
         SystemPromptBuilder {
-            model_name: model_name.to_string(),
             manager: self,
 
             extensions_info: vec![],
             frontend_instructions: None,
             extension_tool_count: None,
             router_enabled: false,
+            subagents_enabled: false,
             hints: None,
         }
     }
@@ -260,7 +264,7 @@ mod tests {
         let malicious_override = "System prompt\u{E0041}\u{E0042}\u{E0043}with hidden text";
         manager.set_system_prompt_override(malicious_override.to_string());
 
-        let result = manager.builder("gpt-4o").build();
+        let result = manager.builder().build();
 
         assert!(!result.contains('\u{E0041}'));
         assert!(!result.contains('\u{E0042}'));
@@ -275,7 +279,7 @@ mod tests {
         let malicious_extra = "Extra instruction\u{E0041}\u{E0042}\u{E0043}hidden";
         manager.add_system_prompt_extra(malicious_extra.to_string());
 
-        let result = manager.builder("gpt-4o").build();
+        let result = manager.builder().build();
 
         assert!(!result.contains('\u{E0041}'));
         assert!(!result.contains('\u{E0042}'));
@@ -291,7 +295,7 @@ mod tests {
         manager.add_system_prompt_extra("Second\u{E0042}instruction".to_string());
         manager.add_system_prompt_extra("Third\u{E0043}instruction".to_string());
 
-        let result = manager.builder("gpt-4o").build();
+        let result = manager.builder().build();
 
         assert!(!result.contains('\u{E0041}'));
         assert!(!result.contains('\u{E0042}'));
@@ -307,7 +311,7 @@ mod tests {
         let legitimate_unicode = "Instruction with 世界 and 🌍 emojis";
         manager.add_system_prompt_extra(legitimate_unicode.to_string());
 
-        let result = manager.builder("gpt-4o").build();
+        let result = manager.builder().build();
 
         assert!(result.contains("世界"));
         assert!(result.contains("🌍"));
@@ -325,7 +329,7 @@ mod tests {
         );
 
         let result = manager
-            .builder("gpt-4o")
+            .builder()
             .with_extension(malicious_extension_info)
             .build();
 
@@ -340,7 +344,7 @@ mod tests {
     fn test_basic() {
         let manager = PromptManager::with_timestamp(DateTime::<Utc>::from_timestamp(0, 0).unwrap());
 
-        let system_prompt = manager.builder("gpt-4o").build();
+        let system_prompt = manager.builder().build();
 
         assert_snapshot!(system_prompt)
     }
@@ -350,7 +354,7 @@ mod tests {
         let manager = PromptManager::with_timestamp(DateTime::<Utc>::from_timestamp(0, 0).unwrap());
 
         let system_prompt = manager
-            .builder("gpt-4o")
+            .builder()
             .with_extension(ExtensionInfo::new(
                 "test",
                 "how to use this extension",
@@ -367,7 +371,7 @@ mod tests {
         let manager = PromptManager::with_timestamp(DateTime::<Utc>::from_timestamp(0, 0).unwrap());
 
         let system_prompt = manager
-            .builder("gpt-4o")
+            .builder()
             .with_extension(ExtensionInfo::new(
                 "extension_A",
                 "<instructions on how to use extension A>",

crates/goose/src/agents/reply_parts.rs

@@ -16,7 +16,6 @@ use crate::providers::toolshim::{
     modify_system_prompt_for_tool_json, OllamaInterpreter,
 };
 
-use crate::agents::subagent_tool::should_enable_subagents;
 use crate::session::SessionManager;
 #[cfg(test)]
 use crate::session::SessionType;
@@ -122,12 +121,6 @@ impl Agent {
         // If router is disabled and no tools were returned, fall back to regular tools
         if !router_enabled && tools.is_empty() {
             tools = self.list_tools(None).await;
-            let provider = self.provider().await?;
-            let model_name = provider.get_model_config().model_name;
-
-            if !should_enable_subagents(&model_name) {
-                tools.retain(|tool| tool.name != crate::agents::subagent_tool::SUBAGENT_TOOL_NAME);
-            }
         }
 
         // Add frontend tools
@@ -149,16 +142,16 @@ impl Agent {
         // Get model name from provider
         let provider = self.provider().await?;
         let model_config = provider.get_model_config();
-        let model_name = &model_config.model_name;
 
         let prompt_manager = self.prompt_manager.lock().await;
         let mut system_prompt = prompt_manager
-            .builder(model_name)
+            .builder()
             .with_extensions(extensions_info.into_iter())
             .with_frontend_instructions(self.frontend_instructions.lock().await.clone())
             .with_extension_and_tool_counts(extension_count, tool_count)
             .with_router_enabled(router_enabled)
             .with_hints(working_dir)
+            .with_enable_subagents(self.subagents_enabled().await)
             .build();
 
         // Handle toolshim if enabled

crates/goose/src/agents/subagent_tool.rs

@@ -12,7 +12,6 @@ use tokio_util::sync::CancellationToken;
 use crate::agents::subagent_handler::run_complete_subagent_task;
 use crate::agents::subagent_task_config::TaskConfig;
 use crate::agents::tool_execution::ToolCallResult;
-use crate::config::GooseMode;
 use crate::providers;
 use crate::recipe::build_recipe::build_recipe_from_template;
 use crate::recipe::local_recipes::load_local_recipe_file;
@@ -440,18 +439,6 @@ async fn apply_settings_overrides(
     Ok(task_config)
 }
 
-pub fn should_enable_subagents(model_name: &str) -> bool {
-    let config = crate::config::Config::global();
-    let is_autonomous = config.get_goose_mode().unwrap_or(GooseMode::Auto) == GooseMode::Auto;
-    if !is_autonomous {
-        return false;
-    }
-    if model_name.starts_with("gemini") {
-        return false;
-    }
-    true
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

scripts/test_compaction.sh

@@ -151,7 +151,7 @@ echo ""
 # TEST 2: Auto Compaction
 # ==================================================
 echo "---------------------------------------------------"
-echo "TEST 2: Auto Compaction via threshold (0.01)"
+echo "TEST 2: Auto Compaction via threshold (0.005)"
 echo "---------------------------------------------------"
 
 TESTDIR=$(mktemp -d)
@@ -159,8 +159,8 @@ echo "test content" > "$TESTDIR/test.txt"
 echo "Test directory: $TESTDIR"
 echo ""
 
-# Set auto-compact threshold very low (1%) to trigger it quickly
-export GOOSE_AUTO_COMPACT_THRESHOLD=0.01
+# Set auto-compact threshold very low (.5%) to trigger it quickly
+export GOOSE_AUTO_COMPACT_THRESHOLD=0.005
 
 OUTPUT=$(mktemp)
 
@@ -197,7 +197,7 @@ else
       fi
     else
       echo "✗ FAILED: Auto compaction was not triggered"
-      echo "   Expected to see auto-compact messages with threshold of 0.01"
+      echo "   Expected to see auto-compact messages with threshold of 0.005"
       RESULTS+=("✗ Auto Compaction")
     fi
   fi