What is bls_mcp CLAUDE.md?

A CLAUDE.md instruction document for a standalone server that provides U.S. Bureau of Labor Statistics data through the Model Context Protocol. The server uses sample JSON data and includes tools for Consumer Price Index data and charts.

Use it as project guidance when working on the server, its data tools, its local testing transport, its remote access transport, or its sample data files.

It gives an AI coding assistant the project’s purpose, architecture, data flow, and development conventions in one place. This reduces guesswork when changing the server.

How kovashikawa/bls_mcp configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to kovashikawa/bls_mcp. 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/kovashikawa/bls_mcp/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/kovashikawa/bls_mcp

Made for: Claude Code.

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/kovashikawa/bls_mcp/claude-md/github.svg)](https://agentmods.dev/instructions/kovashikawa/bls_mcp/claude-md)

Your own site

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

Per session 1,774 This file is loaded in full into every session.

When invoked 1,774 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	$0.01774	$0.01774
Opus 5.5	$0.00710	$0.00710
Sonnet 5.5	$0.00355	$0.00355
Haiku 4.5	$0.00177	$0.00177

Measured 2mo ago against content hash c13076c15fe5, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

bls_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 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.

CLAUDE.md · 239 lines

How it starts

The opening of the file, as written. The whole thing — 239 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

A standalone Model Context Protocol (MCP) server for Bureau of Labor Statistics (BLS) data. Built with the official mcp Python SDK, this server provides tools for accessing CPI (Consumer Price Index) data through mock data fixtures. Currently in Phase 2 with visualization capabilities.

Key Architecture

MCP Server Design

The server uses the official MCP SDK (not FastMCP) with:

stdio transport for local testing and Claude Desktop integration
SSE transport for remote access via ngrok
Tool-based architecture where each tool inherits from BaseTool
Mock data provider that loads from JSON fixtures on-demand with lazy loading

Data Flow

MCP Client (Claude Desktop, etc.)
    ↓ JSON-RPC over stdio/SSE
BLSMCPServer (server.py)
    ↓ tool routing
Tool classes (get_series.py, plot_series.py, etc.)
    ↓ async data fetching
MockDataProvider (mock_data.py)
    ↓ lazy load from fixtures/
JSON fixtures (cpi_series.json, historical_data.json)

Tool Pattern

All tools follow this pattern:

Inherit from BaseTool abstract class
Define name, description, and input_schema (Pydantic model)
Implement async execute(arguments) method
Return structured dict with status and data/error
Input validation happens via Pydantic before execution

Critical Implementation Details

plot_series returns data, not images: The tool returns structured JSON data suitable for client-side plotting, not pre-rendered images. This is more stable across different LLM clients (ChatGPT, Claude, etc.).
Lazy data loading: Mock data loads from JSON fixtures only when first accessed and caches in memory
Multiple server entry points: bls-mcp (stdio) and bls-mcp-ngrok (SSE) defined in pyproject.toml
No matplotlib dependency: The plot_series tool no longer requires matplotlib - it just formats and returns data

Read the full file on GitHub · 239 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 · 239 lines · 1,774 tokens per session scan A c13076c15fe5

Subscribe to this mod's changes

bls_mcp CLAUDE.md is an instructions file published in the GitHub repository kovashikawa/bls_mcp (0 stars, last pushed 1y ago), licensed MIT. It adds 1,774 tokens to every session, about $0.0071 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.

Backend and APIs Data and AI

bls_mcp CLAUDE.md next to 6 instructions from other repositories
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bls_mcp: Instructions file for Claude Code