🤖 refactor: remove plan subagent auto-handoff by ammar-agent · Pull Request #3033 · coder/mux

ammar-agent · 2026-03-19T14:56:35Z

Summary

Remove plan-mode subagent auto-handoff after propose_plan, along with the executor-routing settings and backend router that supported it.

Background

Plan auto-handoff originally let plan-mode subagents compact into a plan and continue under exec or orchestrator. In practice it now collides with grouped task workflows: planning-only best-of batches can silently turn into implementation work. Removing the feature restores a clearer boundary: planning stays top-level, and task subagents stay implementation-oriented.

Implementation

removed the taskService stream-end handoff path that compacted history, switched agents, and posted synthetic Implement the plan / orchestrator kickoff messages
removed the plan-to-executor routing config surface from task settings, the settings UI, and the dedicated router/status modules
made the built-in plan agent non-runnable as a subagent again and added a task creation guard that rejects any plan-like subagent, including custom agents that inherit from plan
deleted the obsolete plan auto-routing story and updated orchestrator/docs copy to direct complex planning back to top-level plan workspaces instead of subagent auto-handoff

Validation

bun test src/common/types/tasks.test.ts
bun test src/node/services/taskService.test.ts
make static-check

Risks

Low-to-moderate. This intentionally removes an existing subagent workflow, so users relying on plan subagents that automatically continue into implementation will need to do planning in a top-level workspace instead. The change reduces surprising execution fan-out, and the new creation-time rejection keeps custom plan-like subagents from falling into an unsupported half-working state.

Generated with mux • Model: openai:gpt-5.4 • Thinking: high • Cost: $2.78

ammar-agent · 2026-03-19T14:56:45Z

@codex review

ammar-agent · 2026-03-19T15:02:41Z

@codex review

ammar-agent · 2026-03-19T15:06:25Z

@codex review

ammar-agent · 2026-03-19T15:10:55Z

@codex review

ammar-agent · 2026-03-19T15:13:34Z

@codex review

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 3f8068019b

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

src/node/builtinAgents/orchestrator.md

ammar-agent · 2026-03-19T15:25:43Z

@codex review

Please take another look.

chatgpt-codex-connector

💡 Codex Review

mux/src/node/services/taskService.ts

Lines 3076 to 3080 in bb69d48

    
           if (status !== "awaiting_report") { 
        
             await this.setTaskStatus(workspaceId, "awaiting_report"); 
        
           } 
        
           await this.promptTaskForRequiredCompletionTool(workspaceId, { reason: "stream_end" });

Treat successful propose_plan as terminal task completion

This path now always pushes plan-like tasks into awaiting_report recovery without first checking whether event.parts already contains a successful propose_plan result, so legacy/in-flight plan-like subagent tasks (e.g. after upgrading with existing tasks) can get stuck in a loop where they are repeatedly told to call propose_plan and never finalize or clean up. Before this change, a successful propose_plan stream-end had a dedicated terminal path; removing it without a replacement leaves affected tasks non-terminating.

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

ammar-agent · 2026-03-19T15:40:39Z

@codex review

Please take another look.

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 4709f2c0a5

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

src/node/services/taskService.ts

ammar-agent · 2026-03-19T15:54:44Z

@codex review

Please take another look.

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: e3dcf9da6c

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

src/node/services/taskService.ts

ammar-agent · 2026-03-19T16:02:54Z

@codex review

Please take another look.

chatgpt-codex-connector

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 56f491a3de

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

src/node/services/taskService.ts

ammar-agent · 2026-03-19T16:13:27Z

@codex review

Please take another look.

chatgpt-codex-connector · 2026-03-19T16:19:21Z

Codex Review: Didn't find any major issues. Chef's kiss.

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

Remove plan-mode subagent auto-handoff after propose_plan, drop the executor-routing settings and backend router, reject plan-like task creation, and update related docs/stories/tests. --- _Generated with `mux` • Model: `openai:gpt-5.4` • Thinking: `high` • Cost: `$2.78`_

ammar-agent · 2026-03-19T16:21:57Z

@codex review

Please take another look.

chatgpt-codex-connector · 2026-03-19T16:28:57Z

Codex Review: Didn't find any major issues. Breezy!

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

Open a pull request for review
Mark a draft as ready
Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

mintlify bot deployed to staging - docs March 19, 2026 14:57 View deployment

ammar-agent force-pushed the refactor/remove-plan-subagent-auto-handoff branch from 8843ab7 to 6e2c2b6 Compare March 19, 2026 15:02

mintlify bot deployed to staging - docs March 19, 2026 15:02 View deployment

ammar-agent force-pushed the refactor/remove-plan-subagent-auto-handoff branch from 6e2c2b6 to 3a7546c Compare March 19, 2026 15:06

mintlify bot deployed to staging - docs March 19, 2026 15:06 View deployment

ammar-agent force-pushed the refactor/remove-plan-subagent-auto-handoff branch from 3a7546c to 22b8eaa Compare March 19, 2026 15:10

mintlify bot deployed to staging - docs March 19, 2026 15:11 View deployment

ammar-agent force-pushed the refactor/remove-plan-subagent-auto-handoff branch from 22b8eaa to 3f80680 Compare March 19, 2026 15:13

mintlify bot deployed to staging - docs March 19, 2026 15:14 View deployment

chatgpt-codex-connector bot reviewed Mar 19, 2026

View reviewed changes

src/node/builtinAgents/orchestrator.md Show resolved Hide resolved

ammar-agent force-pushed the refactor/remove-plan-subagent-auto-handoff branch from 3f80680 to bb69d48 Compare March 19, 2026 15:25

mintlify bot deployed to staging - docs March 19, 2026 15:26 View deployment

chatgpt-codex-connector bot reviewed Mar 19, 2026

View reviewed changes

ammar-agent force-pushed the refactor/remove-plan-subagent-auto-handoff branch from bb69d48 to 4709f2c Compare March 19, 2026 15:40

mintlify bot deployed to staging - docs March 19, 2026 15:41 View deployment

chatgpt-codex-connector bot reviewed Mar 19, 2026

View reviewed changes

src/node/services/taskService.ts Show resolved Hide resolved

ammar-agent force-pushed the refactor/remove-plan-subagent-auto-handoff branch from 4709f2c to e3dcf9d Compare March 19, 2026 15:54

mintlify bot deployed to staging - docs March 19, 2026 15:55 View deployment

chatgpt-codex-connector bot reviewed Mar 19, 2026

View reviewed changes

src/node/services/taskService.ts Show resolved Hide resolved

ammar-agent force-pushed the refactor/remove-plan-subagent-auto-handoff branch from e3dcf9d to 56f491a Compare March 19, 2026 16:02

mintlify bot deployed to staging - docs March 19, 2026 16:03 View deployment

chatgpt-codex-connector bot reviewed Mar 19, 2026

View reviewed changes

src/node/services/taskService.ts Show resolved Hide resolved

ammar-agent force-pushed the refactor/remove-plan-subagent-auto-handoff branch from 56f491a to cfa04b9 Compare March 19, 2026 16:13

mintlify bot deployed to staging - docs March 19, 2026 16:14 View deployment

ammar-agent force-pushed the refactor/remove-plan-subagent-auto-handoff branch from cfa04b9 to 351c772 Compare March 19, 2026 16:21

mintlify bot deployed to staging - docs March 19, 2026 16:22 View deployment

	if (status !== "awaiting_report") {
	await this.setTaskStatus(workspaceId, "awaiting_report");
	}

	await this.promptTaskForRequiredCompletionTool(workspaceId, { reason: "stream_end" });

Conversation

ammar-agent commented Mar 19, 2026

Summary

Background

Implementation

Validation

Risks

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

chatgpt-codex-connector bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

chatgpt-codex-connector bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

chatgpt-codex-connector bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

chatgpt-codex-connector bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

chatgpt-codex-connector bot left a comment

Choose a reason for hiding this comment

💡 Codex Review

Uh oh!

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

chatgpt-codex-connector bot commented Mar 19, 2026

Uh oh!

ammar-agent commented Mar 19, 2026

Uh oh!

chatgpt-codex-connector bot commented Mar 19, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant