What is starfetch AGENTS.md?

A set of project instructions for agents contributing to Starfetch, a TypeScript and npm project for querying astronomical data. It defines the project’s boundaries, package responsibilities, and supported agent interfaces.

Use it when modifying Starfetch’s core library, MCP server, command-line tool, packaged skill, or private HTTP application.

It gives coding agents consistent rules for where changes belong and which parts of the project should not be expanded.

How starfetch-js/starfetch configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to starfetch-js/starfetch. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/starfetch-js/starfetch/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/starfetch-js/starfetch

Made for: Codex, OpenCode.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/starfetch-js/starfetch/agents-md/github.svg)](https://agentmods.dev/instructions/starfetch-js/starfetch/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/starfetch-js/starfetch/agents-md"><img src="https://agentmods.dev/badge/instructions/starfetch-js/starfetch/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/starfetch-js/starfetch/agents-md"><img src="https://agentmods.dev/badge/instructions/starfetch-js/starfetch/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 2,436 This file is loaded in full into every session.

When invoked 2,436 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.02436	$0.02436
Opus 5.5	$0.00974	$0.00974
Sonnet 5.5	$0.00487	$0.00487
Haiku 4.5	$0.00244	$0.00244

Measured 2mo ago against content hash da17db5802ac, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

starfetch 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 2mo 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.

AGENTS.md · 263 lines

How it starts

The opening of the file, as written. The whole thing — 263 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Starfetch Agent Guide

This file is contributor guidance for humans and coding agents working on Starfetch.

Project Boundary

Starfetch is a TypeScript/npm astronomical data querying project. The main surfaces are agent-ready TAP/ADQL access through a local MCP server, a scriptable CLI, and a distributable agent skill. The reusable TypeScript library powers those surfaces and is available for direct callers.

Keep the package boundaries tight:

@starfetch-js/core owns TAP protocol behavior, VOSI metadata, VOTable parsing, output conversion, presets, registry discovery, async jobs, and typed errors.
@starfetch-js/mcp is a thin MCP adapter over @starfetch-js/core.
apps/mcp-app is a private Streamable HTTP host that constructs a fresh @starfetch-js/mcp server and transport for each request. It owns only HTTP policy, request lifecycle, and process shutdown.
@starfetch-js/skill owns packaged static skill files and install helpers.
starfetch is the CLI package and should stay a thin caller over @starfetch-js/core and @starfetch-js/skill.

Do not expand the current pre-1.0 scope into broad VO protocol support, Gaia-only workflows, GUI workflows, full ADQL parsing, or authenticated TAP flows unless a later issue explicitly changes scope.

The root README.md is the single human-facing repository guide. Package READMEs are concise npm package-page summaries, and packaged skill Markdown is a product asset consumed by agents and MCP resources. Do not create a parallel docs/ hierarchy for user guides, demonstrations, or architecture notes unless a later issue explicitly changes this policy. Keep private launch planning, campaign tracking, raw media, and historical working notes outside the public repository.

Runtime and Package Policy

The implementation is an npm workspace with TypeScript ESM packages:

root private workspace package;
packages/core is @starfetch-js/core;
packages/cli is starfetch;
packages/mcp is @starfetch-js/mcp;
packages/skill is @starfetch-js/skill.
apps/mcp-app is the private @starfetch-js/mcp-app development host.

Read the full file on GitHub · 263 lines

Changes

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.

2mo ago First seen · 263 lines · 2,436 tokens per session scan A da17db5802ac

Subscribe to this mod's changes

starfetch AGENTS.md is an instructions file published in the GitHub repository starfetch-js/starfetch (1 stars, last pushed 1mo ago), licensed MIT. It adds 2,436 tokens to every session, about $0.0097 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 2026-08-31.

Languages Scientific TypeScript adql ai-agents astronomy gaia mcp simbad

starfetch AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
starfetch AGENTS.mdstarfetch-js/starfetch	Instructions file	1	1mo ago	MIT	A	2,436	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

starfetch: Instructions file for Codex