Add configurable goal token budget limits (#37878)

## What changed

- Add `goals.max_goal_token_budget` as a positive-integer configuration setting.
- Use the configured maximum as the default budget for new goals and when `tokenBudget` is reset to `null`.
- Reject goal creation and updates whose token budget exceeds the configured maximum, including requests through goal tools and `thread/goal/set`.
- Respect managed configuration precedence and per-thread configuration overrides.

## Testing

- Cover configuration parsing and managed overrides.
- Cover defaulting, resetting, and rejecting oversized budgets through the goal service, goal tools, and app-server API.

GitOrigin-RevId: f8d7e6418cdc237d454c8cf47bb32ba0d44a60cf

codex-rs/app-server/README.md

@@ -717,6 +717,8 @@ Experimental: use `memory/reset` to clear local memory artifacts and sqlite-back
 
 Use `thread/goal/set` to create or update the current goal for a materialized thread. Clients can set `budgetLimited` when they stop because a token budget is exhausted or nearly exhausted, `blocked` when progress is waiting on outside intervention, and `usageLimited` when usage availability stops further work. The system also sets `budgetLimited` when accounting crosses a configured token budget and `usageLimited` when a turn ends on a hard usage-limit error.
 
+When `goals.max_goal_token_budget` is configured, new goals default to that limit, larger budgets are rejected, and setting `tokenBudget` to `null` resets the budget to the configured limit instead of removing it.
+
 ```json
 { "method": "thread/goal/set", "id": 27, "params": {
     "threadId": "thr_123",

codex-rs/app-server/src/extensions.rs

@@ -18,6 +18,7 @@ use codex_extension_api::ExtensionEventSink;
 use codex_extension_api::ExtensionRegistry;
 use codex_extension_api::ExtensionRegistryBuilder;
 use codex_extension_api::ExtensionWarning;
+use codex_goal_extension::GoalExtensionConfig;
 use codex_goal_extension::GoalService;
 use codex_http_client::HttpClientFactory;
 use codex_login::AuthManager;
@@ -85,7 +86,10 @@ where
             codex_otel::global(),
             thread_manager,
             goal_service,
-            |config: &Config| config.features.enabled(codex_features::Feature::Goals),
+            |config: &Config| GoalExtensionConfig {
+                enabled: config.features.enabled(codex_features::Feature::Goals),
+                max_goal_token_budget: config.max_goal_token_budget,
+            },
         );
     }
     codex_git_attribution::install(

codex-rs/app-server/src/request_processors/thread_goal_processor.rs

@@ -122,6 +122,10 @@ impl ThreadGoalRequestProcessor {
         let state_db = self.state_db_for_materialized_thread(thread_id).await?;
         self.reconcile_thread_goal_rollout(thread_id, &state_db)
             .await?;
+        let max_goal_token_budget = match self.thread_manager.get_thread(thread_id).await {
+            Ok(thread) => thread.config().await.max_goal_token_budget,
+            Err(_) => self.config.max_goal_token_budget,
+        };
 
         let listener_command_tx = {
             let thread_state = self.thread_state_manager.thread_state(thread_id).await;
@@ -145,6 +149,7 @@ impl ThreadGoalRequestProcessor {
                         Some(token_budget) => GoalTokenBudgetUpdate::Set(token_budget),
                         None => GoalTokenBudgetUpdate::Keep,
                     },
+                    max_goal_token_budget,
                 },
             )
             .await

codex-rs/app-server/tests/suite/v2/thread_resume.rs

@@ -2051,6 +2051,103 @@ async fn thread_resume_keeps_paused_goal_paused() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test]
+async fn thread_goal_set_enforces_configured_maximum_token_budget() -> Result<()> {
+    let server = create_mock_responses_server_repeating_assistant("Done").await;
+    let codex_home = TempDir::new()?;
+    mock_responses_config(&server.uri()).write(codex_home.path())?;
+    let config_path = codex_home.path().join("config.toml");
+    let config = std::fs::read_to_string(&config_path)?;
+    let config = config.replace("personality = true\n", "personality = true\ngoals = true\n");
+    std::fs::write(
+        config_path,
+        format!("{config}\n[goals]\nmax_goal_token_budget = 200\n"),
+    )?;
+
+    let mut mcp = TestAppServer::builder()
+        .with_codex_home(codex_home.path())
+        .without_managed_config()
+        .build_initialized()
+        .await?;
+    let start_id = mcp
+        .send_thread_start_request_with_auto_env(ThreadStartParams {
+            model: Some("gpt-5.2-codex".to_string()),
+            config: Some(
+                [("goals.max_goal_token_budget".to_string(), json!(100))]
+                    .into_iter()
+                    .collect(),
+            ),
+            ..Default::default()
+        })
+        .await?;
+    let ThreadStartResponse { thread, .. } =
+        timeout(DEFAULT_READ_TIMEOUT, mcp.read_response(start_id)).await??;
+
+    let oversized_creation_id = mcp
+        .send_raw_request(
+            "thread/goal/set",
+            Some(json!({
+                "threadId": thread.id,
+                "objective": "oversized goal",
+                "tokenBudget": 101,
+            })),
+        )
+        .await?;
+    let creation_error: JSONRPCError = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_error_message(RequestId::Integer(oversized_creation_id)),
+    )
+    .await??;
+    assert_eq!(
+        creation_error.error.message,
+        "goal token budget 101 exceeds the maximum allowed goal token budget of 100"
+    );
+
+    let creation_id = mcp
+        .send_raw_request(
+            "thread/goal/set",
+            Some(json!({
+                "threadId": thread.id,
+                "objective": "bounded goal",
+            })),
+        )
+        .await?;
+    let creation: ThreadGoalSetResponse =
+        timeout(DEFAULT_READ_TIMEOUT, mcp.read_response(creation_id)).await??;
+    assert_eq!(creation.goal.token_budget, Some(100));
+
+    let clear_budget_id = mcp
+        .send_raw_request(
+            "thread/goal/set",
+            Some(json!({ "threadId": thread.id, "tokenBudget": null })),
+        )
+        .await?;
+    let clear_budget: ThreadGoalSetResponse =
+        timeout(DEFAULT_READ_TIMEOUT, mcp.read_response(clear_budget_id)).await??;
+    assert_eq!(clear_budget.goal.token_budget, Some(100));
+
+    let oversized_update_id = mcp
+        .send_raw_request(
+            "thread/goal/set",
+            Some(json!({
+                "threadId": thread.id,
+                "tokenBudget": 101,
+            })),
+        )
+        .await?;
+    let update_error: JSONRPCError = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_error_message(RequestId::Integer(oversized_update_id)),
+    )
+    .await??;
+    assert_eq!(
+        update_error.error.message,
+        "goal token budget 101 exceeds the maximum allowed goal token budget of 100"
+    );
+
+    Ok(())
+}
+
 #[tokio::test]
 async fn thread_goal_set_preserves_budget_limited_same_objective() -> Result<()> {
     let server = create_mock_responses_server_repeating_assistant("Done").await;

codex-rs/config/src/config_toml.rs

@@ -2,6 +2,7 @@
 
 use std::collections::BTreeMap;
 use std::collections::HashMap;
+use std::num::NonZeroU64;
 use std::path::Path;
 
 use crate::HooksToml;
@@ -432,6 +433,9 @@ pub struct ConfigToml {
     /// Agent-related settings (thread limits, etc.).
     pub agents: Option<AgentsToml>,
 
+    /// Goal-related settings.
+    pub goals: Option<GoalsToml>,
+
     /// Memories subsystem settings.
     pub memories: Option<MemoriesToml>,
 
@@ -683,6 +687,13 @@ where
     })
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, Default, PartialEq, Eq, JsonSchema)]
+#[schemars(deny_unknown_fields)]
+pub struct GoalsToml {
+    /// Maximum token budget allowed for a goal and default budget for new goals.
+    pub max_goal_token_budget: Option<NonZeroU64>,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, Default, PartialEq, Eq, JsonSchema)]
 #[schemars(deny_unknown_fields)]
 pub struct AgentsToml {

codex-rs/core/config.schema.json

@@ -1199,6 +1199,18 @@
       },
       "type": "object"
     },
+    "GoalsToml": {
+      "additionalProperties": false,
+      "properties": {
+        "max_goal_token_budget": {
+          "description": "Maximum token budget allowed for a goal and default budget for new goals.",
+          "format": "uint64",
+          "minimum": 1.0,
+          "type": "integer"
+        }
+      },
+      "type": "object"
+    },
     "GranularApprovalConfig": {
       "properties": {
         "mcp_elicitations": {
@@ -5521,6 +5533,14 @@
       "default": null,
       "description": "Compatibility-only settings retained so legacy `ghost_snapshot` config still loads."
     },
+    "goals": {
+      "allOf": [
+        {
+          "$ref": "#/definitions/GoalsToml"
+        }
+      ],
+      "description": "Goal-related settings."
+    },
     "hide_agent_reasoning": {
       "default": false,
       "description": "When set to `true`, `AgentReasoning` events will be hidden from the UI/output. Defaults to `false`.",

codex-rs/core/src/config/config_loader_tests.rs

@@ -800,6 +800,36 @@ extra = true
     assert_eq!(nested.get("extra"), Some(&TomlValue::Boolean(true)));
 }
 
+#[tokio::test]
+async fn managed_goal_token_budget_overrides_user_config() -> anyhow::Result<()> {
+    let tmp = tempdir()?;
+    let managed_path = tmp.path().join("managed_config.toml");
+    std::fs::write(
+        tmp.path().join(CONFIG_TOML_FILE),
+        "[goals]\nmax_goal_token_budget = 20000\n",
+    )?;
+    std::fs::write(&managed_path, "[goals]\nmax_goal_token_budget = 5000\n")?;
+
+    let state = load_config_layers_state(
+        LOCAL_FS.as_ref(),
+        tmp.path(),
+        Some(AbsolutePathBuf::try_from(tmp.path())?),
+        &[] as &[(String, TomlValue)],
+        LoaderOverrides::with_managed_config_path_for_tests(managed_path),
+        &codex_config::NoopThreadConfigLoader,
+    )
+    .await?;
+
+    assert_eq!(
+        state
+            .effective_config()
+            .get("goals")
+            .and_then(|goals| goals.get("max_goal_token_budget")),
+        Some(&TomlValue::Integer(5_000))
+    );
+    Ok(())
+}
+
 #[tokio::test]
 async fn returns_empty_when_all_layers_missing() {
     let tmp = tempdir().expect("tempdir");

codex-rs/core/src/config/config_tests.rs

@@ -326,6 +326,28 @@ consolidation_model = "gpt-5.2"
     );
 }
 
+#[tokio::test]
+async fn goal_max_token_budget_requires_positive_integer() {
+    let config_toml = toml::from_str::<ConfigToml>("[goals]\nmax_goal_token_budget = 25000\n")
+        .expect("positive goal token budget should deserialize");
+    let config = Config::load_from_base_config_with_overrides(
+        config_toml,
+        ConfigOverrides::default(),
+        tempdir().expect("tempdir").abs(),
+    )
+    .await
+    .expect("positive goal token budget should load");
+    assert_eq!(config.max_goal_token_budget, Some(25_000));
+
+    for invalid in ["0", "-1", "1.5", "\"100\""] {
+        let config = format!("[goals]\nmax_goal_token_budget = {invalid}\n");
+        assert!(
+            toml::from_str::<ConfigToml>(&config).is_err(),
+            "invalid goal token budget should be rejected: {invalid}"
+        );
+    }
+}
+
 #[test]
 fn parses_bundled_skills_config() {
     let cfg: ConfigToml = toml::from_str(

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

@@ -898,6 +898,9 @@ pub struct Config {
     /// User-defined role declarations keyed by role name.
     pub agent_roles: BTreeMap<String, AgentRoleConfig>,
 
+    /// Maximum token budget allowed for a goal and default budget for new goals.
+    pub max_goal_token_budget: Option<i64>,
+
     /// Memories subsystem settings.
     pub memories: MemoriesConfig,
 
@@ -4193,6 +4196,19 @@ impl Config {
             agent_default_subagent_reasoning_effort,
             agent_max_depth,
             agent_roles,
+            max_goal_token_budget: cfg
+                .goals
+                .as_ref()
+                .and_then(|goals| goals.max_goal_token_budget)
+                .map(|max_goal_token_budget| {
+                    i64::try_from(max_goal_token_budget.get()).map_err(|_| {
+                        std::io::Error::new(
+                            std::io::ErrorKind::InvalidInput,
+                            "goals.max_goal_token_budget exceeds the maximum supported token budget",
+                        )
+                    })
+                })
+                .transpose()?,
             memories: memories_config,
             agent_interrupt_message_enabled,
             codex_home,

codex-rs/ext/goal/src/api.rs

@@ -54,6 +54,7 @@ pub struct GoalSetRequest<'a> {
     pub objective: GoalObjectiveUpdate<'a>,
     pub status: Option<ThreadGoalStatus>,
     pub token_budget: GoalTokenBudgetUpdate,
+    pub max_goal_token_budget: Option<i64>,
 }
 
 #[derive(Clone, Debug)]
@@ -150,6 +151,7 @@ impl GoalService {
             objective,
             status,
             token_budget,
+            max_goal_token_budget,
         } = request;
         let status = status.map(state_status_from_protocol);
         let objective = match objective {
@@ -158,14 +160,16 @@ impl GoalService {
         };
         let token_budget = match token_budget {
             GoalTokenBudgetUpdate::Keep => None,
-            GoalTokenBudgetUpdate::Set(token_budget) => Some(token_budget),
+            GoalTokenBudgetUpdate::Set(token_budget) => {
+                Some(token_budget.or(max_goal_token_budget))
+            }
         };
 
         if let Some(objective) = objective {
             validate_thread_goal_objective(objective).map_err(GoalServiceError::InvalidRequest)?;
         }
         if objective.is_some() || token_budget.is_some() {
-            validate_goal_budget(token_budget.flatten())
+            validate_goal_budget(token_budget.flatten(), max_goal_token_budget)
                 .map_err(GoalServiceError::InvalidRequest)?;
         }
 
@@ -225,7 +229,7 @@ impl GoalService {
                         thread_id,
                         objective,
                         status.unwrap_or(codex_state::ThreadGoalStatus::Active),
-                        token_budget.flatten(),
+                        token_budget.flatten().or(max_goal_token_budget),
                     )
                     .await
                     .map_err(|err| {

codex-rs/ext/goal/src/extension.rs

@@ -48,12 +48,7 @@ use crate::tool::GoalToolExecutor;
 #[derive(Clone, Debug)]
 pub struct GoalExtensionConfig {
     pub enabled: bool,
-}
+    pub max_goal_token_budget: Option<i64>,
-
-impl GoalExtensionConfig {
-    fn from_enabled(enabled: bool) -> Self {
-        Self { enabled }
-    }
 }
 
 #[derive(Clone)]
@@ -64,7 +59,7 @@ pub struct GoalExtension<C> {
     metrics: GoalMetrics,
     thread_manager: Weak<ThreadManager>,
     goal_service: Arc<GoalService>,
-    goals_enabled: Arc<dyn Fn(&C) -> bool + Send + Sync>,
+    goal_config: Arc<dyn Fn(&C) -> GoalExtensionConfig + Send + Sync>,
 }
 
 impl<C> std::fmt::Debug for GoalExtension<C> {
@@ -81,7 +76,7 @@ impl<C> GoalExtension<C> {
         metrics_client: Option<MetricsClient>,
         thread_manager: Weak<ThreadManager>,
         goal_service: Arc<GoalService>,
-        goals_enabled: impl Fn(&C) -> bool + Send + Sync + 'static,
+        goal_config: impl Fn(&C) -> GoalExtensionConfig + Send + Sync + 'static,
     ) -> Self {
         Self {
             state_dbs,
@@ -90,7 +85,7 @@ impl<C> GoalExtension<C> {
             metrics: GoalMetrics::new(metrics_client),
             thread_manager,
             goal_service,
-            goals_enabled: Arc::new(goals_enabled),
+            goal_config: Arc::new(goal_config),
         }
     }
 }
@@ -101,15 +96,14 @@ where
 {
     fn on_thread_start<'a>(&'a self, input: ThreadStartInput<'a, C>) -> ExtensionFuture<'a, ()> {
         Box::pin(async move {
-            let enabled = (self.goals_enabled)(input.config);
+            let config = (self.goal_config)(input.config);
+            let enabled = config.enabled;
             let tools_available_for_thread = input.persistent_thread_state_available
                 && !matches!(
                     input.session_source,
                     SessionSource::SubAgent(SubAgentSource::Review)
                 );
-            input
+            input.thread_store.insert(config);
-                .thread_store
-                .insert(GoalExtensionConfig::from_enabled(enabled));
             let accounting_state = input
                 .thread_store
                 .get_or_init::<GoalAccountingState>(GoalAccountingState::default);
@@ -186,8 +180,9 @@ where
         _previous_config: &C,
         new_config: &C,
     ) {
-        let enabled = (self.goals_enabled)(new_config);
+        let config = (self.goal_config)(new_config);
-        thread_store.insert(GoalExtensionConfig::from_enabled(enabled));
+        let enabled = config.enabled;
+        thread_store.insert(config);
         if let Some(runtime) = goal_runtime_handle(thread_store) {
             runtime.set_enabled(enabled);
         }
@@ -427,6 +422,9 @@ where
         if !runtime.tools_visible() {
             return Vec::new();
         }
+        let max_goal_token_budget = thread_store
+            .get::<GoalExtensionConfig>()
+            .and_then(|config| config.max_goal_token_budget);
 
         vec![
             Arc::new(GoalToolExecutor::get(
@@ -444,6 +442,7 @@ where
                 self.analytics.clone(),
                 self.event_emitter.clone(),
                 self.metrics.clone(),
+                max_goal_token_budget,
             )),
             Arc::new(GoalToolExecutor::update(
                 runtime.thread_id(),
@@ -464,7 +463,7 @@ pub fn install_with_backend<C>(
     metrics_client: Option<MetricsClient>,
     thread_manager: Weak<ThreadManager>,
     goal_service: Arc<GoalService>,
-    goals_enabled: impl Fn(&C) -> bool + Send + Sync + 'static,
+    goal_config: impl Fn(&C) -> GoalExtensionConfig + Send + Sync + 'static,
 ) where
     C: Send + Sync + 'static,
 {
@@ -475,7 +474,7 @@ pub fn install_with_backend<C>(
         metrics_client,
         thread_manager,
         Arc::clone(&goal_service),
-        goals_enabled,
+        goal_config,
     ));
     registry.thread_lifecycle_contributor(extension.clone());
     registry.config_contributor(extension.clone());

codex-rs/ext/goal/src/tool.rs

@@ -36,6 +36,7 @@ pub(crate) struct GoalToolExecutor {
     analytics: GoalAnalytics,
     event_emitter: GoalEventEmitter,
     metrics: GoalMetrics,
+    max_goal_token_budget: Option<i64>,
 }
 
 #[derive(Clone, Copy)]
@@ -89,6 +90,7 @@ impl GoalToolExecutor {
             analytics,
             event_emitter,
             metrics,
+            max_goal_token_budget: None,
         }
     }
 
@@ -99,6 +101,7 @@ impl GoalToolExecutor {
         analytics: GoalAnalytics,
         event_emitter: GoalEventEmitter,
         metrics: GoalMetrics,
+        max_goal_token_budget: Option<i64>,
     ) -> Self {
         Self {
             kind: GoalToolKind::Create,
@@ -108,6 +111,7 @@ impl GoalToolExecutor {
             analytics,
             event_emitter,
             metrics,
+            max_goal_token_budget,
         }
     }
 
@@ -127,6 +131,7 @@ impl GoalToolExecutor {
             analytics,
             event_emitter,
             metrics,
+            max_goal_token_budget: None,
         }
     }
 }
@@ -185,7 +190,9 @@ impl GoalToolExecutor {
         request.objective = request.objective.trim().to_string();
         validate_thread_goal_objective(&request.objective)
             .map_err(FunctionCallError::RespondToModel)?;
-        validate_goal_budget(request.token_budget).map_err(FunctionCallError::RespondToModel)?;
+        request.token_budget = request.token_budget.or(self.max_goal_token_budget);
+        validate_goal_budget(request.token_budget, self.max_goal_token_budget)
+            .map_err(FunctionCallError::RespondToModel)?;
 
         let goal = self
             .state_db
@@ -397,12 +404,23 @@ where
         .map_err(|err| FunctionCallError::RespondToModel(err.to_string()))
 }
 
-pub(crate) fn validate_goal_budget(value: Option<i64>) -> Result<(), String> {
+pub(crate) fn validate_goal_budget(
+    value: Option<i64>,
+    max_goal_token_budget: Option<i64>,
+) -> Result<(), String> {
     if let Some(value) = value
         && value <= 0
     {
         return Err("goal budgets must be positive when provided".to_string());
     }
+    if let Some(value) = value
+        && let Some(max_goal_token_budget) = max_goal_token_budget
+        && value > max_goal_token_budget
+    {
+        return Err(format!(
+            "goal token budget {value} exceeds the maximum allowed goal token budget of {max_goal_token_budget}"
+        ));
+    }
     Ok(())
 }
 

codex-rs/ext/goal/tests/goal_extension_backend.rs

@@ -27,6 +27,7 @@ use codex_extension_api::ToolPayload;
 use codex_extension_api::TurnErrorInput;
 use codex_extension_api::TurnStartInput;
 use codex_extension_api::TurnStopInput;
+use codex_goal_extension::GoalExtensionConfig;
 use codex_goal_extension::GoalObjectiveUpdate;
 use codex_goal_extension::GoalRuntimeHandle;
 use codex_goal_extension::GoalService;
@@ -97,6 +98,55 @@ async fn installed_goal_tools_create_goal_and_fill_empty_preview() -> anyhow::Re
     Ok(())
 }
 
+#[tokio::test]
+async fn installed_goal_tools_apply_maximum_token_budget() -> anyhow::Result<()> {
+    let runtime = test_runtime().await?;
+    let thread_id = test_thread_id()?;
+    seed_thread_metadata(runtime.as_ref(), thread_id).await?;
+    let harness = GoalExtensionHarness::new(runtime.clone(), thread_id).await?;
+    harness.thread_store.insert(GoalExtensionConfig {
+        enabled: true,
+        max_goal_token_budget: Some(100),
+    });
+    let tools = harness.tools();
+    let create_tool = tool_by_name(&tools, "create_goal");
+
+    let result = create_tool
+        .handle(tool_call(
+            "create_goal",
+            "call-oversized-goal",
+            json!({ "objective": "oversized goal", "token_budget": 101 }),
+        ))
+        .await;
+    let error = match result {
+        Ok(_) => panic!("goal budget above the configured maximum should fail"),
+        Err(error) => error,
+    };
+    assert_eq!(
+        error,
+        FunctionCallError::RespondToModel(
+            "goal token budget 101 exceeds the maximum allowed goal token budget of 100"
+                .to_string()
+        )
+    );
+    assert_eq!(
+        runtime.thread_goals().get_thread_goal(thread_id).await?,
+        None
+    );
+
+    let invocation = tool_call(
+        "create_goal",
+        "call-default-goal-budget",
+        json!({ "objective": "default goal budget" }),
+    );
+    let output = create_tool.handle(invocation.clone()).await?;
+    assert_eq!(
+        output.code_mode_result(&invocation.payload)["goal"]["tokenBudget"],
+        json!(100)
+    );
+    Ok(())
+}
+
 #[tokio::test]
 async fn goal_tools_hidden_for_ephemeral_threads() -> anyhow::Result<()> {
     let runtime = test_runtime().await?;
@@ -940,6 +990,7 @@ async fn goal_service_external_set_active_resets_baseline_without_live_thread()
                 objective: GoalObjectiveUpdate::Set("new objective"),
                 status: Some(ThreadGoalStatus::Active),
                 token_budget: GoalTokenBudgetUpdate::Keep,
+                max_goal_token_budget: None,
             },
         )
         .await?;
@@ -1069,6 +1120,7 @@ async fn goal_service_sets_gets_and_clears_thread_goal() -> anyhow::Result<()> {
                 objective: GoalObjectiveUpdate::Set(" ship goal API ownership "),
                 status: None,
                 token_budget: GoalTokenBudgetUpdate::Set(Some(123)),
+                max_goal_token_budget: None,
             },
         )
         .await?;
@@ -1096,6 +1148,84 @@ async fn goal_service_sets_gets_and_clears_thread_goal() -> anyhow::Result<()> {
     Ok(())
 }
 
+#[tokio::test]
+async fn goal_service_enforces_maximum_token_budget_on_creation_and_updates() -> anyhow::Result<()>
+{
+    let runtime = test_runtime().await?;
+    let thread_id = test_thread_id()?;
+    seed_thread_metadata(runtime.as_ref(), thread_id).await?;
+    let service = GoalService::new();
+
+    let goal = service
+        .set_thread_goal(
+            runtime.as_ref(),
+            GoalSetRequest {
+                thread_id,
+                objective: GoalObjectiveUpdate::Set("bounded goal"),
+                status: None,
+                token_budget: GoalTokenBudgetUpdate::Keep,
+                max_goal_token_budget: Some(100),
+            },
+        )
+        .await?;
+    assert_eq!(goal.goal.token_budget, Some(100));
+
+    let error = service
+        .set_thread_goal(
+            runtime.as_ref(),
+            GoalSetRequest {
+                thread_id,
+                objective: GoalObjectiveUpdate::Keep,
+                status: None,
+                token_budget: GoalTokenBudgetUpdate::Set(Some(101)),
+                max_goal_token_budget: Some(100),
+            },
+        )
+        .await
+        .expect_err("goal budget above the configured maximum should fail");
+    assert_eq!(
+        error.to_string(),
+        "goal token budget 101 exceeds the maximum allowed goal token budget of 100"
+    );
+    assert_eq!(
+        service
+            .get_thread_goal(runtime.as_ref(), thread_id)
+            .await?
+            .expect("goal should remain unchanged")
+            .token_budget,
+        Some(100)
+    );
+
+    let goal = service
+        .set_thread_goal(
+            runtime.as_ref(),
+            GoalSetRequest {
+                thread_id,
+                objective: GoalObjectiveUpdate::Keep,
+                status: None,
+                token_budget: GoalTokenBudgetUpdate::Set(Some(99)),
+                max_goal_token_budget: Some(100),
+            },
+        )
+        .await?;
+    assert_eq!(goal.goal.token_budget, Some(99));
+
+    let goal = service
+        .set_thread_goal(
+            runtime.as_ref(),
+            GoalSetRequest {
+                thread_id,
+                objective: GoalObjectiveUpdate::Keep,
+                status: None,
+                token_budget: GoalTokenBudgetUpdate::Set(None),
+                max_goal_token_budget: Some(100),
+            },
+        )
+        .await?;
+    assert_eq!(goal.goal.token_budget, Some(100));
+    Ok(())
+}
+
 async fn installed_tools(
     runtime: Arc<codex_state::StateRuntime>,
     thread_id: ThreadId,
@@ -1124,7 +1254,10 @@ async fn installed_tools_with_start(
         /*metrics_client*/ None,
         Weak::new(),
         goal_service,
-        |_| true,
+        |_| GoalExtensionConfig {
+            enabled: true,
+            max_goal_token_budget: None,
+        },
     );
     let registry = builder.build();
     let session_store = ExtensionData::new("session-1");
@@ -1178,7 +1311,10 @@ impl GoalExtensionHarness {
             /*metrics_client*/ None,
             Weak::new(),
             Arc::clone(&goal_service),
-            |_| true,
+            |_| GoalExtensionConfig {
+                enabled: true,
+                max_goal_token_budget: None,
+            },
         );
         let registry = builder.build();
         let session_store = ExtensionData::new("session-1");

codex-rs/thread-manager-sample/src/main.rs

@@ -303,6 +303,7 @@ fn new_config(model: Option<String>, arg0_paths: Arg0DispatchPaths) -> anyhow::R
         background_terminal_max_timeout: 300_000,
         ghost_snapshot: GhostSnapshotConfig::default(),
         multi_agent_v2: MultiAgentV2Config::default(),
+        max_goal_token_budget: None,
         token_budget: None,
         rollout_budget: None,
         current_time_reminder: None,