chore: enable parallel tc

codex-rs/core/gpt-5.1-codex-max_prompt.md

@@ -4,6 +4,19 @@ You are Codex, based on GPT-5. You are running as a coding agent in the Codex CL
 
 - When searching for text or files, prefer using `rg` or `rg --files` respectively because `rg` is much faster than alternatives like `grep`. (If the `rg` command is not found, then use alternatives.)
 
+## Exploration and reading files
+
+- **Think first.** Before any tool call, decide ALL files/resources you will need.
+- **Batch everything.** If you need multiple files (even from different places), read them together.
+- **multi_tool_use.parallel** Use `multi_tool_use.parallel` to parallelize tool calls and only this.
+- **Only make sequential calls if you truly cannot know the next file without seeing a result first.**
+- **Workflow:** (a) plan all needed reads → (b) issue one parallel batch → (c) analyze results → (d) repeat if new, unpredictable reads arise.
+
+**Additional notes**:
+* Always maximize parallelism. Never read files one-by-one unless logically unavoidable.
+* This concern every read/list/search operations including, but not only, `cat`, `rg`, `sed`, `ls`, `git show`, `nl`, `wc`, ...
+* Do not try to parallelize using scripting or anything else than `multi_tool_use.parallel`.
+
 ## Editing constraints
 
 - Default to ASCII when editing or creating files. Only introduce non-ASCII or other Unicode characters when there is a clear justification and the file already uses them.

codex-rs/core/gpt_5_1_prompt.md

@@ -366,3 +366,16 @@ To create a new plan, call `update_plan` with a short list of 1‑sentence steps
 When steps have been completed, use `update_plan` to mark each finished step as `completed` and the next step you are working on as `in_progress`. There should always be exactly one `in_progress` step until everything is done. You can mark multiple items as complete in a single `update_plan` call.
 
 If all steps are complete, ensure you call `update_plan` to mark all steps as `completed`.
+
+## Exploration and reading files
+
+- **Think first.** Before any tool call, decide ALL files/resources you will need.
+- **Batch everything.** If you need multiple files (even from different places), read them together.
+- **multi_tool_use.parallel** Use `multi_tool_use.parallel` to parallelize tool calls and only this.
+- **Only make sequential calls if you truly cannot know the next file without seeing a result first.**
+- **Workflow:** (a) plan all needed reads → (b) issue one parallel batch → (c) analyze results → (d) repeat if new, unpredictable reads arise.
+
+**Additional notes**:
+* Always maximize parallelism. Never read files one-by-one unless logically unavoidable.
+* This concern every read/list/search operations including, but not only, `cat`, `rg`, `sed`, `ls`, `git show`, `nl`, `wc`, ...
+* Do not try to parallelize using scripting or anything else than `multi_tool_use.parallel`.

codex-rs/core/src/codex.rs

@@ -2144,24 +2144,11 @@ async fn run_turn(
         .get_model_family()
         .supports_parallel_tool_calls;
 
-    // TODO(jif) revert once testing phase is done.
-    let parallel_tool_calls = model_supports_parallel && sess.enabled(Feature::ParallelToolCalls);
-    let mut base_instructions = turn_context.base_instructions.clone();
-    if parallel_tool_calls {
-        static INSTRUCTIONS: &str = include_str!("../templates/parallel/instructions.md");
-        let family = sess
-            .services
-            .models_manager
-            .construct_model_family(&sess.state.lock().await.session_configuration.model);
-        let mut new_instructions = base_instructions.unwrap_or(family.base_instructions);
-        new_instructions.push_str(INSTRUCTIONS);
-        base_instructions = Some(new_instructions);
-    }
     let prompt = Prompt {
         input,
         tools: router.specs(),
-        parallel_tool_calls,
-        base_instructions_override: base_instructions,
+        parallel_tool_calls: model_supports_parallel && sess.enabled(Feature::ParallelToolCalls),
+        base_instructions_override: turn_context.base_instructions.clone(),
         output_schema: turn_context.final_output_json_schema.clone(),
     };
 

codex-rs/core/src/features.rs

@@ -263,6 +263,12 @@ pub const FEATURES: &[FeatureSpec] = &[
         stage: Stage::Stable,
         default_enabled: true,
     },
+    FeatureSpec {
+        id: Feature::ParallelToolCalls,
+        key: "parallel",
+        stage: Stage::Stable,
+        default_enabled: true,
+    },
     FeatureSpec {
         id: Feature::ViewImageTool,
         key: "view_image_tool",
@@ -324,12 +330,6 @@ pub const FEATURES: &[FeatureSpec] = &[
         stage: Stage::Experimental,
         default_enabled: true,
     },
-    FeatureSpec {
-        id: Feature::ParallelToolCalls,
-        key: "parallel",
-        stage: Stage::Experimental,
-        default_enabled: false,
-    },
     FeatureSpec {
         id: Feature::ModelWarnings,
         key: "warnings",

codex-rs/core/src/openai_models/model_family.rs

@@ -212,7 +212,7 @@ pub fn find_family_for_model(slug: &str) -> ModelFamily {
             base_instructions: GPT_5_CODEX_INSTRUCTIONS.to_string(),
             apply_patch_tool_type: Some(ApplyPatchToolType::Freeform),
             shell_type: ConfigShellToolType::ShellCommand,
-            supports_parallel_tool_calls: true,
+            supports_parallel_tool_calls: false,
             support_verbosity: false,
             truncation_policy: TruncationPolicy::Tokens(10_000),
         )