Borrowing it
Nothing to install: this file belongs to cyanheads/astronomy-mcp-server. 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/cyanheads/astronomy-mcp-server/main/AGENTS.mdgit clone --depth 1 https://github.com/cyanheads/astronomy-mcp-serverWrote 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/instructions/cyanheads/astronomy-mcp-server/agents-md)<a href="https://agentmods.dev/instructions/cyanheads/astronomy-mcp-server/agents-md"><img src="https://agentmods.dev/badge/instructions/cyanheads/astronomy-mcp-server/agents-md.svg" alt="Measured on agentmods" height="20"></a>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 | $0.07425 | $0.07425 |
| Opus 5 | $0.03712 | $0.03712 |
| Sonnet 5 | $0.01485 | $0.01485 |
| Haiku 4.5 | $0.00743 | $0.00743 |
Grade A, and why
astronomy-mcp-server 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 7d 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.
This is a copy
72% identical to obsidian-mcp-server AGENTS.md — 370 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 451 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Developer Protocol
Server: astronomy-mcp-server
Version: 0.2.9
Framework: @cyanheads/mcp-ts-core ^0.12.3
Engines: Bun ≥1.3.0, Node ≥24.0.0
MCP SDK: @modelcontextprotocol/server ^2.0.0
Zod: ^4.4.3
Read the framework docs first:
node_modules/@cyanheads/mcp-ts-core/CLAUDE.mdcontains the full API reference — builders, Context, error codes, exports, patterns. This file covers server-specific conventions only.
Server Surface
Observational astronomy, computed in-process. The core is keyless and offline — astronomy-engine plus a bundled bright-star catalog, no upstream, no ctx.state, deterministic for (body, time, observer). The server does not geocode: callers resolve a place name to latitude/longitude (e.g. via openstreetmap) and a timezone (e.g. via reference-data) upstream, then pass coordinates and an optional IANA timezone for observer-local output.
Five core tools (always registered):
| Tool | What it computes |
|---|---|
astronomy_get_sky_position |
Apparent topocentric position of one body or named star — equatorial / horizontal / ecliptic, magnitude, angular diameter, phase, constellation |
astronomy_get_rise_set |
Rise / set / transit cycles, plus twilight bands for the Sun; circumpolar / never-rises notes |
astronomy_get_moon_phase |
Phase angle, illumination, synodic age, next four quarter phases |
astronomy_find_events |
Next N of: equinox, solstice, moon_quarter, lunar/solar eclipse, opposition, conjunction, max_elongation, perigee_apogee |
astronomy_list_visible |
One-call "what is up now" — naked-eye bodies (+ optional catalog stars) above the horizon, ranked, with a sky-condition gate |
Plus the astronomy://body/{body} resource (static reference card) and the astronomy_stargazing_plan prompt (chains the tools for a "plan tonight from " workflow).
Two gated, network-backed extensions register only when their env gate is on (default deployment is keyless + offline):
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.
- 7d ago First seen · 451 lines · 7,425 tokens per session scan A 351ab872c44a
astronomy-mcp-server AGENTS.md is an instructions file published in the GitHub repository cyanheads/astronomy-mcp-server (2 stars, last pushed 13d ago), licensed Apache-2.0. It adds 7,425 tokens to every session, about $0.0371 per session on Opus 5. A static security scan graded it A with 0 findings. It is 72% identical to obsidian-mcp-server AGENTS.md, differing in 370 lines, and is treated as a copy.
Other instructions, from other repositories
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