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/firstmate-coding-guidelines/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/firstmate-coding-guidelines)<a href="https://agentmods.dev/skills/kunchenguid/firstmate/firstmate-coding-guidelines"><img src="https://agentmods.dev/badge/skills/kunchenguid/firstmate/firstmate-coding-guidelines/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/firstmate-coding-guidelines"><img src="https://agentmods.dev/badge/skills/kunchenguid/firstmate/firstmate-coding-guidelines.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 | $0.00049 | $0.02489 |
| Opus 5.5 | $0.00020 | $0.00996 |
| Sonnet 5.5 | $0.00010 | $0.00498 |
| Haiku 4.5 | $0.00005 | $0.00249 |
Grade A, and why
firstmate-coding-guidelines 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 4d ago.
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 — 134 lines — stays where its author put it; the contents beside it link to each section on GitHub.
firstmate-coding-guidelines
Load this before changing firstmate's shared, tracked material, as defined by AGENTS.md section 1.
It exists because AGENTS.md grew from 585 to 958 lines between its last two restructures, entirely from conditional detail added inline instead of routed to its right home.
Applying the rules below on every change is what keeps that from happening again.
Knowledge-placement decision tree
Before writing a new fact anywhere in this repo, ask where it belongs, in this order.
- Does the firstmate AGENT need this on every session or every turn to operate?
If yes:
AGENTS.md, inline. - Does the agent need it only in a nameable situation - a spawn, a recovery, a specific wake type, a specific lifecycle step?
If yes: an agent-only skill under
.agents/skills/, whose description states its load trigger; leave a one-line inline pointer inAGENTS.mdonly when an always-loaded rule must name the skill. - Is it public product, setup, or user/operator reference?
If yes: the surface classified for that audience in
docs/documentation-audiences.md, limited to current behavior, setup, supported limits, stable invariants, concise rationale, and current verification entry points. - Is it contributor/maintainer architecture? If yes: the classified maintainer-architecture owner for stable ownership, extension points, mechanism boundaries, and safety rationale.
- Is it active reusable verification for a current guarantee? If yes: an explicitly classified maintainer-verification record may keep current dates, versions, exact commands, and exact output.
- Is it task or incident evidence - chronology, transcripts, branches, temporary paths, failed hypotheses, or delivery proof? If yes: keep it in the private task report or PR evidence by default, after distilling every unique current fact into its authoritative owner.
- Is it mechanics - exact flags, exact commands, exact paths?
If yes: the script's own header comment plus its
--helpoutput, not prose inAGENTS.md, a skill, or a second documentation owner.
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.
- 4d ago Changed · -2 lines · -81 tokens per session 46c315e13804
- 11d ago Changed a79564c062f3
- 27d ago Changed · +1 lines 4e557b86b4bf
- 1mo ago Changed 1fd826284d88
- 1mo ago Changed 03fb90a70778
- 1mo ago Changed · +7 lines db401077bf8a
- 1mo ago First seen · 128 lines · 130 tokens per session scan A ca7bd8f24f56
firstmate-coding-guidelines is a skill published in the GitHub repository kunchenguid/firstmate (8,295 stars, last pushed today), licensed MIT. It adds 49 tokens to every session and 2,489 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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