Borrowing it
Nothing to install: this file belongs to lucianfialho/build-in-public-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.
curl -O https://raw.githubusercontent.com/lucianfialho/build-in-public-mcp/main/CLAUDE.mdgit clone --depth 1 https://github.com/lucianfialho/build-in-public-mcpWrote 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/lucianfialho/build-in-public-mcp/claude-md)<a href="https://agentmods.dev/instructions/lucianfialho/build-in-public-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/lucianfialho/build-in-public-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.
<a href="https://agentmods.dev/instructions/lucianfialho/build-in-public-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/lucianfialho/build-in-public-mcp/claude-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 | $0.01726 | $0.01726 |
| Opus 5 | $0.00863 | $0.00863 |
| Sonnet 5 | $0.00345 | $0.00345 |
| Haiku 4.5 | $0.00173 | $0.00173 |
Grade A, and why
build-in-public-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 10d 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 — 207 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
Build in Public MCP Server is an MCP (Model Context Protocol) server that enables developers to share their coding progress on Twitter directly from Claude Code. It analyzes coding sessions and generates AI-powered tweet suggestions about achievements, learnings, and progress.
Development Commands
Build and Development
# Build TypeScript to JavaScript
npm run build
# Watch mode for development (auto-rebuild on changes)
npm run dev
# Start the MCP server
npm start
Testing
# No tests currently configured
npm test # Returns error - tests not implemented yet
Installation & Publishing
# Install dependencies
npm install
# Global installation (for testing)
npm install -g .
# Add to Claude Code via npx (recommended for users)
claude mcp add --transport stdio build-in-public npx @lucianfialho/build-in-public-mcp
# Add to Claude Code via global install
claude mcp add --transport stdio build-in-public build-in-public-mcp
Architecture
MCP Server Design (STDIO Transport)
This is an MCP server that communicates with Claude Code using STDIO transport. The architecture follows this pattern:
Claude Code ←→ STDIO ←→ MCP Server (local process) ←→ Twitter API
↓
~/.build-in-public/
- auth.json (OAuth tokens)
- context.json (Session context)
- history.json (Tweet history)
Key architectural points:
- 100% local - No external servers or databases
- STDIO transport - Uses stdin/stdout for MCP protocol communication (stderr for logging)
- Session-based - Tracks coding sessions and generates suggestions based on accumulated context
- OAuth 1.0a - PIN-based Twitter authentication flow
Entry Point
src/index.ts is the main entry point that:
- Initializes the MCP server using
@modelcontextprotocol/sdk - Registers MCP tools and prompts
- Sets up STDIO transport for Claude Code integration
- Handles all tool call requests
- Uses stderr for logging (stdout is reserved for MCP protocol)
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.
- 10d ago First seen · 207 lines · 1,726 tokens per session scan A fa403a9bfa55
build-in-public-mcp CLAUDE.md is an instructions file published in the GitHub repository lucianfialho/build-in-public-mcp (9 stars, last pushed 5mo ago), licensed MIT. It adds 1,726 tokens to every session, about $0.0086 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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