agentmods.dev

census-mcp CLAUDE.md

A set of coding instructions for census-mcp, an MCP server that brings U.S. Census data into AI agents as part of the mcpwright server collection.

In plain words
What is it for?
Use it when developing, testing, or releasing census-mcp and keeping it consistent with the collection's standards.
Why use it?
It defines shared engineering rules for testing, SDK usage, typed results, mocked external access, and publishing.

Instructions file

0 13d ago A scan 1,142 tokens original MIT
View the source file mcpwright/census-mcp
Install

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.

agentmods
npx agentmods add instructions/mcpwright/census-mcp/claude-md
Clone the repo
git clone --depth 1 https://github.com/mcpwright/census-mcp
Per session 1,142 This file is loaded in full into every session.
When invoked 1,142 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.01142 $0.01142
Opus 5 $0.00571 $0.00571
Sonnet 5 $0.00228 $0.00228
Haiku 4.5 $0.00114 $0.00114

Measured 2d ago against content hash 8efd51f1b9e4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

census-mcp CLAUDE.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.

CLAUDE.md · 72 lines

How it starts

The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.

census-mcp — working agreement

census-mcp is a server in the mcpwright suite (github.com/mcpwright): polished, public MCP servers that bring a real-world data source into any agent. Every server in the suite meets the same engineering bar, set by the reference server edgar-mcp.

Source of truth: edgar-mcp. When a convention here is unclear, copy edgar (~/github-personal/edgar-mcp). The full written rubric is ~/my-notes/professional-self-improvement/mcpwright/mcp-standards.md. To scaffold/extend to standard, use the new-mcpwright-server skill.

Non-negotiable policies

  • Lots of unit tests. Every tool and every parser/formatter has tests. Mock all external I/O (respx for HTTP; a seeded temp SQLite store for the local data). A new tool ships with its tests in the same PR. pytest -v must be green before a PR opens.
  • Use the latest patterns. Official mcp Python SDK via mcp.server.fastmcp (NOT the standalone fastmcp package). Python 3.12+ idioms, from __future__ import annotations, pydantic v2 models with a Field(description=...) on every field, uv for deps + build, async httpx. Tools return typed pydantic models (structured output) and are annotated readOnlyHint=True.
  • PR per change, CI-gated. Standard flow: feature branch → code → code-review subagent → fold in findings → PR → CI green → squash-merge.
    • Code-review subagent: before opening the PR, review the diff (git diff main...HEAD) with the code-reviewer subagent (.claude/agents/code-reviewer.md) — or just run /review-pr. It runs in a fresh context with no memory of the coding session and returns severity-tagged findings (Blocker / High / Medium / Low). Address Blocker/High (and add a regression test for any real bug) before the PR.
    • Merge: the Code Quality & Tests check green and branch up to date → squash-merge with a (#N) suffix. main is branch-protected; no direct pushes.
    • Commits: imperative subject + a short body, ending with the dual trailer (Co-authored-by: Devender … + Co-authored-by: Claude …).
    • One focused change per PR — keep process/docs changes (like this one) out of feature PRs.
  • Green locally before pushing: 
    uv run ruff check src/ && uv run ruff format --check src/ && uv run mypy && uv run pytest -v
    uv run pre-commit run --all-files mirrors CI (ruff, ruff-format, mypy, detect-secrets, hygiene).

Read the full file on GitHub · 72 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.

  1. 2d ago First seen · 72 lines · 1,142 tokens per session scan A 8efd51f1b9e4

Subscribe to this mod's changes

census-mcp CLAUDE.md is an instructions file published in the GitHub repository mcpwright/census-mcp (0 stars, last pushed 13d ago), licensed MIT. It adds 1,142 tokens to every session, about $0.0057 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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