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/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/instructions/cyanheads/astronomy-mcp-server/agents-md"><img src="https://agentmods.dev/badge/instructions/cyanheads/astronomy-mcp-server/agents-md.svg" alt="Reviewed on agentmods" width="80" 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 | $0.08510 | $0.08510 |
| Opus 5.5 | $0.03404 | $0.03404 |
| Sonnet 5.5 | $0.01702 | $0.01702 |
| Haiku 4.5 | $0.00851 | $0.00851 |
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 — 410 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 — 463 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Developer Protocol
Server: astronomy-mcp-server
Version: 0.4.2
Framework: @cyanheads/mcp-ts-core ^0.13.15
Engines: Bun ≥1.4.0, Node ≥24.0.0
MCP SDK: @modelcontextprotocol/server ^2.3.1
Zod: ^4.6.6
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, Sun elongation, constellation |
astronomy_get_rise_set |
Rise / set / transit cycles (31 per call), plus twilight bands for the Sun and night_in_progress when the start falls at night; circumpolar / never-rises notes |
astronomy_get_moon_phase |
Phase longitude, illumination, synodic age, next four quarter phases |
astronomy_find_events |
Next N (20 per call) of: equinox, solstice, moon_quarter, lunar/solar eclipse, opposition, conjunction (with the Sun, or two bodies via body2), 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).
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 Changed · +131 tokens per session 565da534cb36
- 14d ago Changed · +1 lines · +171 tokens per session fc35683ce63d
- 28d ago Changed · +13 tokens per session 91c54505381c
- 1mo ago Changed · +11 lines · +770 tokens per session 1b49a34b3777
- 1mo 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 (3 stars, last pushed 5d ago), licensed Apache-2.0. It adds 8,510 tokens to every session, about $0.0340 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 72% identical to obsidian-mcp-server AGENTS.md, differing in 410 lines, and is treated as a copy.
Other instructions, from other repositories
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