core: move workspace roots onto environments

codex-rs/app-server-protocol/src/protocol/v2/tests.rs

@@ -4217,13 +4217,15 @@ fn turn_start_params_round_trip_environments() {
     let raw_cwd = r"C:\workspace";
     let cwd: LegacyAppPathString =
         serde_json::from_value(json!(raw_cwd)).expect("API path should deserialize");
+    let workspace_root = cwd.clone();
     let params: TurnStartParams = serde_json::from_value(json!({
         "threadId": "thread_123",
         "input": [],
         "environments": [
             {
                 "environmentId": "local",
-                "cwd": cwd
+                "cwd": cwd,
+                "runtimeWorkspaceRoots": [workspace_root]
             }
         ],
     }))
@@ -4234,6 +4236,7 @@ fn turn_start_params_round_trip_environments() {
         Some(vec![TurnEnvironmentParams {
             environment_id: "local".to_string(),
             cwd: cwd.clone(),
+            runtime_workspace_roots: Some(vec![workspace_root.clone()]),
         }])
     );
     assert_eq!(
@@ -4247,7 +4250,8 @@ fn turn_start_params_round_trip_environments() {
         Some(&json!([
             {
                 "environmentId": "local",
-                "cwd": cwd
+                "cwd": cwd,
+                "runtimeWorkspaceRoots": [workspace_root]
             }
         ]))
     );

codex-rs/app-server-protocol/src/protocol/v2/turn.rs

@@ -41,6 +41,9 @@ pub enum TurnStatus {
 pub struct TurnEnvironmentParams {
     pub environment_id: String,
     pub cwd: LegacyAppPathString,
+    /// Environment-native runtime workspace roots. Omitted defaults to `cwd`.
+    #[ts(optional = nullable)]
+    pub runtime_workspace_roots: Option<Vec<LegacyAppPathString>>,
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq, JsonSchema, TS)]

codex-rs/app-server/README.md

@@ -137,7 +137,7 @@ Example with notification opt-out:
 
 ## API Overview
 
-- `thread/start` — create a new thread; emits `thread/started` (including the current `thread.status`) and auto-subscribes you to turn/item events for that thread. When the request includes a `cwd` and the resolved sandbox is `workspace-write` or full access, app-server also marks that project as trusted in the user `config.toml`. Pass `sessionStartSource: "clear"` when starting a replacement thread after clearing the current session so `SessionStart` hooks receive `source: "clear"` instead of the default `"startup"`. Experimental `allowProviderModelFallback` lets providers backed by an authoritative static model catalog replace an unavailable requested `model` with the catalog default; dynamic or cached catalogs preserve the requested model. Experimental `runtimeWorkspaceRoots` replaces the thread-scoped runtime workspace roots used to materialize `:workspace_roots`; paths must be absolute. For permissions, prefer experimental `permissions` profile selection by id; the legacy `sandbox` shorthand is still accepted but cannot be combined with `permissions`. Deprecated experimental `multiAgentMode` is ignored; use Ultra reasoning effort for proactive multi-agent behavior. Experimental `environments` selects the sticky execution environments for turns on the thread; omit it to use the server default, pass `[]` to disable environments, or pass explicit environment ids with per-environment `cwd`. Experimental `selectedCapabilityRoots` selects environment-owned plugin or standalone-skill roots using environment-native absolute paths. Skills found below those roots are listed and read through the owning environment. Stdio MCP servers declared by selected plugins are started in that environment, and HTTP MCP connections use that environment's HTTP client.
+- `thread/start` — create a new thread; emits `thread/started` (including the current `thread.status`) and auto-subscribes you to turn/item events for that thread. When the request includes a `cwd` and the resolved sandbox is `workspace-write` or full access, app-server also marks that project as trusted in the user `config.toml`. Pass `sessionStartSource: "clear"` when starting a replacement thread after clearing the current session so `SessionStart` hooks receive `source: "clear"` instead of the default `"startup"`. Experimental `allowProviderModelFallback` lets providers backed by an authoritative static model catalog replace an unavailable requested `model` with the catalog default; dynamic or cached catalogs preserve the requested model. Experimental `runtimeWorkspaceRoots` supplies the runtime workspace roots used when app-server creates default environment selections; paths must be absolute. For permissions, prefer experimental `permissions` profile selection by id; the legacy `sandbox` shorthand is still accepted but cannot be combined with `permissions`. Deprecated experimental `multiAgentMode` is ignored; use Ultra reasoning effort for proactive multi-agent behavior. Experimental `environments` selects the sticky execution environments for turns on the thread; omit it to use the server default, pass `[]` to disable environments, or pass explicit environment ids with per-environment `cwd` and optional environment-native `runtimeWorkspaceRoots`. Explicit environments ignore the top-level roots; omitted per-environment roots default to that environment's `cwd`, while an empty list explicitly selects no roots. Experimental `selectedCapabilityRoots` selects environment-owned plugin or standalone-skill roots using environment-native absolute paths. Skills found below those roots are listed and read through the owning environment. Stdio MCP servers declared by selected plugins are started in that environment, and HTTP MCP connections use that environment's HTTP client.
 - `thread/resume` — reopen an existing thread by id so subsequent `turn/start` calls append to it. Accepts the same permission override rules as `thread/start`.
 - `thread/fork` — fork an existing thread into a new thread id by copying the stored history; pass an optional `lastTurnId` to copy history only through that turn, inclusive, and drop later turns from the fork. An in-progress `lastTurnId` is rejected. If `lastTurnId` is null while the source thread is mid-turn, the fork records the same interruption marker as `turn/interrupt` instead of inheriting an unmarked partial turn suffix. The returned `thread.forkedFromId` points at the source thread when known. Accepts `ephemeral: true` for an in-memory temporary fork, emits `thread/started` (including the current `thread.status`), and auto-subscribes you to turn/item events for the new thread. Experimental clients can pass `excludeTurns: true` when they plan to page fork history via `thread/turns/list` instead of receiving the full turn array immediately. Accepts the same permission override rules as `thread/start`.
 - `thread/start`, `thread/resume`, and `thread/fork` responses include the legacy `sandbox` compatibility projection. `instructionSources` lists loaded instruction files using each source environment's native absolute path syntax, including files loaded from remote environments. Experimental clients can read `runtimeWorkspaceRoots` for the thread-scoped runtime roots and `activePermissionProfile` for the named or implicit built-in profile identity/provenance when known. Their deprecated experimental `multiAgentMode` field, and the corresponding thread setting, always report `explicitRequestOnly`; Ultra reasoning effort is the source of proactive multi-agent behavior.
@@ -168,7 +168,7 @@ Example with notification opt-out:
 - `thread/backgroundTerminals/list` — list running background terminals for a loaded thread (experimental; requires `capabilities.experimentalApi`); returns `data` with the running terminal ids.
 - `thread/backgroundTerminals/terminate` — terminate one running background terminal by app-server `processId` (experimental; requires `capabilities.experimentalApi`); returns whether a process was terminated.
 - `thread/rollback` — deprecated and will be removed soon. Drop the last N turns from the agent’s in-memory context and persist a rollback marker in the rollout so future resumes see the pruned history; returns the updated `thread` (with `turns` populated) on success.
-- `turn/start` — add user input to a thread and begin Codex generation; responds with the initial `turn` object and streams `turn/started`, `item/*`, and `turn/completed` notifications. `clientUserMessageId` is optional; when supplied, the corresponding `userMessage` item echoes it as `clientId`. Experimental `runtimeWorkspaceRoots` replaces the thread-scoped runtime workspace roots used to materialize `:workspace_roots`; paths must be absolute. Prefer experimental `permissions` profile selection by id for permission overrides; the legacy `sandboxPolicy` field is still accepted but cannot be combined with `permissions`. For `collaborationMode`, `settings.developer_instructions: null` means "use built-in instructions for the selected mode". Deprecated experimental `multiAgentMode` is ignored; Ultra reasoning effort selects proactive behavior.
+- `turn/start` — add user input to a thread and begin Codex generation; responds with the initial `turn` object and streams `turn/started`, `item/*`, and `turn/completed` notifications. `clientUserMessageId` is optional; when supplied, the corresponding `userMessage` item echoes it as `clientId`. Experimental `runtimeWorkspaceRoots` supplies the default roots for newly resolved environment selections. Explicit `environments[].runtimeWorkspaceRoots` override that fallback with environment-native absolute paths. Prefer experimental `permissions` profile selection by id for permission overrides; the legacy `sandboxPolicy` field is still accepted but cannot be combined with `permissions`. For `collaborationMode`, `settings.developer_instructions: null` means "use built-in instructions for the selected mode". Deprecated experimental `multiAgentMode` is ignored; Ultra reasoning effort selects proactive behavior.
 - `thread/inject_items` — append raw Responses API items to a loaded thread’s model-visible history without starting a user turn; returns `{}` on success.
 - `turn/steer` — add user input to an already in-flight regular turn without starting a new turn; returns the active `turnId` that accepted the input. `clientUserMessageId` is optional; when supplied, the corresponding `userMessage` item echoes it as `clientId`. Review and manual compaction turns reject `turn/steer`.
 - `turn/interrupt` — request cancellation of an in-flight turn by `(thread_id, turn_id)`; success is an empty `{}` response and the turn finishes with `status: "interrupted"`.

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

@@ -580,9 +580,28 @@ fn resolve_turn_environment_selections(
                     environment.cwd
                 ))
             })?;
+        let workspace_roots = environment
+            .runtime_workspace_roots
+            .map(|roots| {
+                let mut resolved_roots = Vec::new();
+                for root in roots {
+                    let root = root.to_inferred_path_uri().ok_or_else(|| {
+                        invalid_request(format!(
+                            "invalid runtime workspace root for environment `{environment_id}`: path `{root}` does not use absolute POSIX or Windows path syntax"
+                        ))
+                    })?;
+                    if !resolved_roots.contains(&root) {
+                        resolved_roots.push(root);
+                    }
+                }
+                Ok::<_, JSONRPCErrorError>(resolved_roots)
+            })
+            .transpose()?
+            .unwrap_or_else(|| vec![cwd.clone()]);
         selections.push(TurnEnvironmentSelection {
             environment_id,
             cwd,
+            workspace_roots,
         });
     }
     thread_manager

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

@@ -619,22 +619,21 @@ pub(super) async fn handle_pending_thread_resume_request(
     }
 
     let config_snapshot = pending.config_snapshot;
+    let sandbox = config_snapshot.sandbox_policy().into();
     let cwd = config_snapshot.cwd().clone();
     let ThreadConfigSnapshot {
         model,
         model_provider_id,
         service_tier,
         approval_policy,
         approvals_reviewer,
-        permission_profile,
         active_permission_profile,
         workspace_roots,
         reasoning_effort,
         originator,
         ..
     } = config_snapshot;
     let instruction_sources = pending.instruction_sources;
-    let sandbox = thread_response_sandbox_policy(&permission_profile, cwd.as_path());
     let active_permission_profile =
         thread_response_active_permission_profile(active_permission_profile);
     let session_id = conversation.session_configured().session_id.to_string();

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

@@ -968,9 +968,9 @@ impl ThreadRequestProcessor {
                 "`permissions` cannot be combined with `sandbox`",
             ));
         }
-        let environment_selections =
-            resolve_turn_environment_selections(self.thread_manager.as_ref(), environments)?;
         let runtime_workspace_roots = runtime_workspace_roots.map(resolve_runtime_workspace_roots);
+        let environments =
+            resolve_turn_environment_selections(self.thread_manager.as_ref(), environments)?;
         let mut typesafe_overrides = self.build_thread_config_overrides(
             model,
             model_provider,
@@ -1017,7 +1017,7 @@ impl ThreadRequestProcessor {
                 history_mode.map(Into::into),
                 session_start_source,
                 thread_source.map(Into::into),
-                environment_selections,
+                environments,
                 service_name,
                 allow_provider_model_fallback,
                 experimental_raw_events,
@@ -1094,7 +1094,7 @@ impl ThreadRequestProcessor {
         history_mode: Option<ThreadHistoryMode>,
         session_start_source: Option<codex_app_server_protocol::ThreadStartSource>,
         thread_source: Option<codex_protocol::protocol::ThreadSource>,
-        environments: Option<Vec<TurnEnvironmentSelection>>,
+        environment_selections: Option<Vec<TurnEnvironmentSelection>>,
         service_name: Option<String>,
         allow_provider_model_fallback: bool,
         experimental_raw_events: bool,
@@ -1107,7 +1107,6 @@ impl ThreadRequestProcessor {
             .load_with_overrides(config_overrides.clone(), typesafe_overrides.clone())
             .await
             .map_err(|err| config_load_error(&err))?;
-
         // The user may have requested WorkspaceWrite or DangerFullAccess via
         // the command line, though in the process of deriving the Config, it
         // could be downgraded to ReadOnly (perhaps there is no sandbox
@@ -1188,10 +1187,10 @@ impl ThreadRequestProcessor {
             }
         }
 
-        let environments = environments.unwrap_or_else(|| {
+        let environments = environment_selections.unwrap_or_else(|| {
             listener_task_context
                 .thread_manager
-                .default_environment_selections(&config.cwd)
+                .default_environment_selections(&config.cwd, &config.workspace_roots)
         });
         let dynamic_tools = dynamic_tools.unwrap_or_default();
         if !dynamic_tools.is_empty() {
@@ -1316,10 +1315,7 @@ impl ThreadRequestProcessor {
             /*has_in_progress_turn*/ false,
         );
 
-        let sandbox = thread_response_sandbox_policy(
-            &config_snapshot.permission_profile,
-            config_snapshot.cwd().as_path(),
-        );
+        let sandbox = config_snapshot.sandbox_policy().into();
         let cwd = config_snapshot.cwd().clone();
         let active_permission_profile =
             thread_response_active_permission_profile(config_snapshot.active_permission_profile);
@@ -2893,10 +2889,7 @@ impl ThreadRequestProcessor {
                     /*has_live_in_progress_turn*/ false,
                 );
                 let config_snapshot = codex_thread.config_snapshot().await;
-                let sandbox = thread_response_sandbox_policy(
-                    &config_snapshot.permission_profile,
-                    config_snapshot.cwd().as_path(),
-                );
+                let sandbox = config_snapshot.sandbox_policy().into();
                 let active_permission_profile = thread_response_active_permission_profile(
                     config_snapshot.active_permission_profile,
                 );
@@ -3655,10 +3648,7 @@ impl ThreadRequestProcessor {
             /*has_in_progress_turn*/ false,
         );
         let config_snapshot = forked_thread.config_snapshot().await;
-        let sandbox = thread_response_sandbox_policy(
-            &config_snapshot.permission_profile,
-            config_snapshot.cwd().as_path(),
-        );
+        let sandbox = config_snapshot.sandbox_policy().into();
         let active_permission_profile =
             thread_response_active_permission_profile(config_snapshot.active_permission_profile);
         let thread_originator = config_snapshot.originator.clone();