firstmate is an agent distribution that lets one coding agent coordinate a crew of autonomous agents working in separate git worktrees. It is for running parallel fixes, investigations, plans, and audits while receiving completed pull requests, merges, or reports through one supervising agent. The catalogue entries provide skills, hooks, instructions, and settings for operating this workflow.
Borrowing it
Nothing to install: this file belongs to kunchenguid/firstmate. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/kunchenguid/firstmate/main/.agents/skills/harness-adapters/SKILL.mdgit clone --depth 1 https://github.com/kunchenguid/firstmateWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/kunchenguid/firstmate/harness-adapters)<a href="https://agentmods.dev/skills/kunchenguid/firstmate/harness-adapters"><img src="https://agentmods.dev/badge/skills/kunchenguid/firstmate/harness-adapters/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/kunchenguid/firstmate/harness-adapters"><img src="https://agentmods.dev/badge/skills/kunchenguid/firstmate/harness-adapters.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00050 | $0.01538 |
| Opus 5.5 | $0.00020 | $0.00615 |
| Sonnet 5.5 | $0.00010 | $0.00308 |
| Haiku 4.5 | $0.00005 | $0.00154 |
Grade A, and why
harness-adapters scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 104 lines — stays where its author put it; the contents beside it link to each section on GitHub.
harness-adapters
This is the one skill, trigger, and routing owner for harness-specific Firstmate operations.
Load this router first, then exactly the common reference and one harness reference selected below.
When an action spans rows, load the union once rather than every reference.
Files under references/ are resources of this skill, not additional catalogued skills.
Path contract
The skill directory is the directory containing this SKILL.md.
Resolve on-demand reference links and relative links to their executable, documentation, or sibling-skill owners against the skill directory, including links named by a nested reference.
Operational paths keep the context named by their owner: config/ and active-home settings belong to the active Firstmate home, state/ belongs to that home, and project settings such as .claude/settings.json belong to the target project.
Non-negotiable safety
Never dispatch a crewmate or secondmate on an unverified adapter.
If config/crew-harness or config/secondmate-harness names one, tell the captain under ../../../AGENTS.md section 9 that the requested worker runtime is not verified, use firstmate's own verified runtime for current work, and ask only whether to verify the requested runtime for future work.
Do not pause current work for that choice.
On unknown, ask the captain instead of guessing.
A current captain override beats detection, while a per-task override governs only that dispatch.
For recovery and control, use the exact harness= in state/<id>.meta; never infer it from a model or provider.
Deliver lifecycle actions only through ../../../bin/fm-control.sh <task-id> interrupt|exit|relaunch.
Never type an interrupt key or exit command through fm-send, where routing-marked lifecycle text becomes chat.
Trust handling is complete only when inspection proves the target started processing its instructions; delivery success alone is not proof.
Muse, Gemini, AGY, Devin, Command Code, Polytoken, and Cortex are verified only for crewmate and scout work, never a secondmate or primary.
What ships with it
20 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- references/common/control-and-recovery.md 3.5 KB
- references/common/dispatch.md 2.7 KB
- references/common/model-and-effort.md 3.1 KB
- references/common/primary-hooks.md 2.6 KB
- references/harness/agy.md 6.2 KB
- references/harness/claude.md 14 KB
- references/harness/codex.md 6.0 KB
- references/harness/commandcode.md 4.4 KB
- references/harness/cortex.md 7.1 KB
- references/harness/cursor.md 7.3 KB
- references/harness/devin.md 4.4 KB
- references/harness/gemini.md 12 KB
- references/harness/grok.md 8.3 KB
- references/harness/kimi.md 8.9 KB
- references/harness/muse.md 5.6 KB
- references/harness/omp.md 7.8 KB
- references/harness/opencode.md 10 KB
- references/harness/pi.md 6.2 KB
- references/harness/polytoken.md 8.5 KB
- references/harness/rovo.md 13 KB
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- today Changed · +1 lines 798d7db63876
- 3d ago Changed 5ff4680b848c
- 4d ago Changed · -2 lines · -59 tokens per session e2f356d0b1c8
- 7d ago Changed · +1 lines · +4 tokens per session f08eccec0966
- 9d ago Changed · +1 lines · +3 tokens per session 9119612436ee
- 1mo ago Changed · +1 lines · +3 tokens per session abc414fd29c3
- 1mo ago Changed · +1 lines 39fbdfc564b7
- 1mo ago Changed · +1 lines · +3 tokens per session 9d0450a6c5d8
- 1mo ago Changed · +2 lines · +2 tokens per session 7358228aaddd
- 1mo ago First seen · 98 lines · 94 tokens per session scan A b7dff5795146
harness-adapters is a skill published in the GitHub repository kunchenguid/firstmate (8,295 stars, last pushed today), licensed MIT. It adds 50 tokens to every session and 1,538 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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