/firstmate-codexapp
**A companion-workflow playbook for visible Codex Desktop threads.**
Skill type: Agent-only
Upstream path:.agents/skills/firstmate-codexapp/SKILL.md
A companion-workflow playbook for visible Codex Desktop threads.
What it does
This skill lets Firstmate coordinate work in a visible Codex Desktop thread using Desktop host tools while refusing to pretend Codex Desktop is a normal selectable shell backend.
A thread becomes truly Firstmate-supervised only when its return channel is proven, typically by writing status into the task's Firstmate status file.
When to reach for it
Load it before creating, reading, steering, archiving, debugging, or reviewing a visible Codex Desktop thread for Firstmate work.
How it behaves
Firstmate checks that it is actually running in Codex Desktop, verifies the target repository already exists as a saved Desktop project, creates and steers threads through the provided host tools, and keeps the Desktop-owned working directory intact.
If the thread cannot write the expected Firstmate status file, it remains a visible companion thread rather than being represented as a fully supervised backend task.
Common questions
Can Firstmate create a missing Codex Desktop project? Not through the current host-tool contract. The human adds the project first.
Should FM_BACKEND=codex-app be invented?
No.
The skill explicitly rejects that shortcut.
It's working if
- The visible thread is attached to the intended saved project.
- Repo work stays in the Desktop-owned working directory.
- The status return channel is verified before claiming supervision.
- Archiving preserves durable landed work and transcript history.
Where it fits
Use it when the value is a visible Desktop-native collaboration surface. Use a normal verified Firstmate backend when standard terminal supervision is the goal.
Upstream: .agents/skills/firstmate-codexapp/SKILL.md