Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add instructions/getpostern/postern/agents-mdgit clone --depth 1 https://github.com/getpostern/posternWhat 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 | $0.00203 | $0.00203 |
| Opus 5 | $0.00102 | $0.00102 |
| Sonnet 5 | $0.00041 | $0.00041 |
| Haiku 4.5 | $0.00020 | $0.00020 |
Grade A, and why
postern AGENTS.md 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 yesterday.
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.
What it actually says
AGENTS.md — superseded by the setup contract
Audience: an agent setting up Postern on behalf of the person who owns the box. This file's old step list and route tables are retired. The replacement is a fuller contract, verified end to end on a clean machine by a first-time user's agent:
Read setup-with-your-agent.md and follow it. It carries the phases in order, every HUMAN stop, the exact routes with body shapes, the never-do-these rules, and the troubleshooting table. Do not improvise a setup path from this file or from the API's shape — that contract exists so you do not have to.
If you are here to change the code instead, read CONTRIBUTING.md and CLAUDE.md. The person-facing, screen-by-screen documentation — and the API reference — is at https://docs.getpostern.com.
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.
- yesterday First seen · 8 lines · 203 tokens per session scan A 571f1ebcd037
postern AGENTS.md is an instructions file published in the GitHub repository getpostern/postern (1 stars, last pushed 22d ago), licensed Apache-2.0. It adds 203 tokens to every session, about $0.0010 per session on Opus 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 2026-08-31.
Other instructions, from other repositories
moira AGENTS.md
Instructions for moira-mcp/moira, covering agents.md, what moira is, repository layout, build & run (fresh clone) and image: line and uncomment the build: block, then.
cortex-gateway AGENTS.md
Instructions for wellknownmcp/cortex-gateway, covering agents.md, what this is, verify the claims yourself, the demo authorization server builds independently and protected-resource metadata (rfc 9728).
ARR_MCP AGENTS.md
Instructions for GauranshMathur/ARR_MCP, covering agents.md, non-negotiables, researching a service, adding a service and tool design.
tooltrust-scanner CLAUDE.md
Instructions for AgentSafe-AI/tooltrust-scanner: Use the /browse skill from gstack for all web browsing. Never use mcpclaude-in-chrome tools.
mcpelevator CLAUDE.md
Instructions for pacnpal/mcpelevator, covering commands, architecture, conventions, agent skills and issue tracker.
ARR_MCP CLAUDE.md
Instructions for GauranshMathur/ARR_MCP, covering claude.md, build and run commands, code style guidelines, agent skills and issue tracker.