obra/private-journal-mcp is an MCP server that gives Claude a local journal for recording and searching thoughts, reflections, notes, and insights. It is intended for private personal and project journaling, with semantic search performed on the user's machine. The catalogue instruction helps coding agents use its journaling workflow.
Borrowing it
Nothing to install: this file belongs to obra/private-journal-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/obra/private-journal-mcp/main/CLAUDE.mdgit clone --depth 1 https://github.com/obra/private-journal-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/obra/private-journal-mcp/claude-md)<a href="https://agentmods.dev/instructions/obra/private-journal-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/obra/private-journal-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/obra/private-journal-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/obra/private-journal-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 | $0.00755 | $0.00755 |
| Opus 5 | $0.00378 | $0.00378 |
| Sonnet 5 | $0.00151 | $0.00151 |
| Haiku 4.5 | $0.00076 | $0.00076 |
Grade A, and why
private-journal-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 9d 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 — 81 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.
Common Development Commands
# Build the project
npm run build
# Run tests
npm test
# Run tests in watch mode
npm run test:watch
# Development mode with TypeScript watcher
npm run dev
# Lint the code
npm run lint
# Format the code
npm run format
# Start the server
npm start
# Run a single test file
npx jest tests/journal.test.ts
Architecture Overview
This is an MCP (Model Context Protocol) server that provides Claude with private journaling capabilities. The architecture consists of:
Core Components:
src/index.ts- CLI entry point with intelligent path resolution for journal storagesrc/server.ts- MCP server using stdio transport with private journaling and search toolssrc/journal.ts- File system operations for timestamped markdown entriessrc/types.ts- TypeScript interfaces for the domain model
Key Architecture Patterns:
- Path Resolution Strategy:
PRIVATE_JOURNAL_PATHenv var overrides all resolution; otherwise falls back through CWD → HOME → temp directories, avoiding system roots - Timestamped Storage: Uses
YYYY-MM-DD/HH-MM-SS-μμμμμμ.mdstructure with microsecond precision - YAML Frontmatter: Each entry includes structured metadata (title, ISO date, Unix timestamp)
- MCP Tool Pattern: Tool registration with schema validation and error handling
File Organization:
- Project journals:
.private-journal/in project root for project-specific notes - Personal journals:
~/.private-journal/for cross-project personal thoughts - Daily structure:
YYYY-MM-DD/HH-MM-SS-μμμμμμ.mdwith microsecond precision - Search index:
.embeddingfiles alongside each journal entry for semantic search - TypeScript compilation to
dist/for production - Jest tests in
tests/directory with comprehensive file system mocking
MCP Integration Details
The server provides comprehensive journaling and search capabilities through these tools:
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.
- 9d ago First seen · 81 lines · 755 tokens per session scan A 71721f8ac915
private-journal-mcp CLAUDE.md is an instructions file published in the GitHub repository obra/private-journal-mcp (442 stars, last pushed 28d ago), licensed MIT. It adds 755 tokens to every session, about $0.0038 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 2026-08-30.
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