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/jaredthivener/fastapi-docs-mcp/copilot-instructionsgit clone --depth 1 https://github.com/jaredthivener/fastapi-docs-mcpWhat 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 | $0.01204 | $0.01204 |
| Opus 5 | $0.00602 | $0.00602 |
| Sonnet 5 | $0.00241 | $0.00241 |
| Haiku 4.5 | $0.00120 | $0.00120 |
Grade A, and why
fastapi-docs-mcp copilot-instructions.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 2d 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 — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.
FastAPI Docs MCP Server — AI Agent Guide
Project Overview
FastAPI Docs MCP is a Model Context Protocol server that provides real-time access to FastAPI documentation via tools. It fetches HTML from fastapi.tiangolo.com, parses content, and exposes 6 tools: get_fastapi_docs, search_fastapi_docs, list_fastapi_pages, get_fastapi_example, compare_fastapi_approaches, and get_fastapi_best_practices.
The entire application is a single-file async tool server (main.py). Focus is on robust HTML parsing and sitemap-driven content discovery.
Key Architecture Patterns
HTML Parsing Without External Dependencies
- No BeautifulSoup: Uses
re.sub()with regex patterns to extract text and code blocks. This is intentional to minimize dependencies. - Extraction pipeline (in
extract_text_from_html()):- Remove non-content elements:
<script>,<style>,<nav>,<footer>,<header> - Extract
<article>tag content (prioritized) - Iteratively strip remaining HTML tags until stable
- Decode HTML entities AFTER tag removal (critical ordering)
- Clean up malformed HTML artifacts
- Remove non-content elements:
- Code extraction (in
extract_code_blocks()): Finds<pre><code>blocks first, then fallback to multi-line<code>blocks. Always removes tags before decoding entities.
Sitemap-Driven Discovery
fetch_sitemap()parsesfastapi.tiangolo.com/sitemap.xmlto get all doc URLscategorize_urls()maps paths to:tutorial,advanced,deployment,how-to,reference,other- Multiple tools (
search_fastapi_docs,get_fastapi_best_practices) dynamically query this list—no hardcoded doc paths except inget_fastapi_example()andcompare_fastapi_approaches()for performance
Keyword Aliasing
search_fastapi_docs()includes alias mappings:auth→security,db→sql-databases,di→dependencies, etc.get_fastapi_example()andcompare_fastapi_approaches()have pre-computedtopic_pathsdicts for direct lookups- Fallback: if no alias matches, search the sitemap directly
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.
- 2d ago First seen · 82 lines · 1,204 tokens per session scan A 9253fd9430cc
fastapi-docs-mcp copilot-instructions.md is an instructions file published in the GitHub repository jaredthivener/fastapi-docs-mcp (3 stars, last pushed 8d ago), licensed MIT. It adds 1,204 tokens to every session, about $0.0060 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.
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