Melchizedek
Persistent memory for Claude Code. Automatically indexes every conversation and provides production-grade hybrid search (BM25 + vectors + reranker) via MCP tools. 100% local, zero config, zero API keys, zero invoice.
Why Melchizedek?
Claude Code forgets everything between sessions - and knows nothing about your other projects. Melchizedek fixes both.
It runs silently in the background - indexing your conversations as you work - then gives Claude the ability to search across your entire history, across all projects: past debugging sessions, architectural decisions, error solutions, code patterns.
No cloud. No API keys. No config. Plug and ask.
How it works
~/.claude/projects/**/*.jsonl (your conversation transcripts - read-only)
|
v
SessionEnd hook (auto-triggers after each session)
|
v
+-----------------+
| Indexer | Parse JSONL -> chunk pairs -> SHA-256 dedup
| (better-sqlite3)| FTS5 tokenize -> vector embed (optional)
+-----------------+
|
v
~/.melchizedek/memory.db (single SQLite file, WAL mode)
|
v
+-----------------+
| MCP Server | 16 search & management tools
| (stdio) | Hybrid: BM25 + vectors + RRF + reranker
+-----------------+
|
v
Claude Code (searches your history via MCP)
Search pipeline - 4 levels of graceful degradation
Every layer is optional. The plugin works with BM25 alone and gets better as more components are available.
| Level | Component | What it adds | Dependency |
|---|
| 1 | BM25 (FTS5) | Keyword search with stemming | None (always active) |
| 2 | Dual vectors (sqlite-vec) | Semantic search - text (MiniLM 384d) + code (Jina 768d) | @huggingface/transformers (optional) |
| 3 | RRF fusion | Merges BM25 + text vectors + code vectors via Reciprocal Rank Fusion | Vectors enabled |
| 4 | Reranker | Cross-encoder re-scoring of top results | Transformers.js or node-llama-cpp (optional) |
Measured with npm run bench - 100 sessions, 1 000 chunks, on a single SQLite file.
| Metric | Result | Target |
|---|
| Indexation (100 sessions) | ~80 ms | < 10 s |
| BM25 search (mean) | ~0.2 ms | < 50 ms |
| DB size (100 sessions) | ~1.4 MB | < 30 MB |
| Tokens per search | ~125 | < 2 000 |
Quick Start
npm (recommended)
npm install -g melchizedek
Add the MCP server to Claude Code:
claude mcp add --scope user melchizedek -- melchizedek-server
npx (no install)
claude mcp add --scope user melchizedek -- npx melchizedek-server
From source
git clone https://github.com/louis49/melchizedek.git
cd melchizedek && npm install && npm run build
claude --mcp-config .mcp.json
Claude Code plugin marketplace (coming soon)
Plugin review pending. In the meantime, use npm or npx install above.
claude plugin install melchizedek
Setting up hooks (automatic indexing)
The MCP server provides search tools, but hooks trigger automatic indexing. Without hooks, you'd need to manually index sessions.
For marketplace installs, hooks are configured automatically. For npm/npx/source installs, add hooks to ~/.claude/settings.json.
See docs/installation.md for the full JSON configuration, hook reference, and troubleshooting.
After setup, restart Claude Code. Indexing starts automatically.
Search (start here)
| Tool | Description |
|---|
m9k_search | Search indexed conversations. Returns compact snippets. Current project boosted. Supports since/until date filters and order (score, date_asc, date_desc). |
m9k_context | Get a chunk with surrounding context (adjacent chunks in the same session). |
m9k_full | Retrieve full content of chunks by IDs. |
Progressive retrieval pattern - search returns ~50 tokens/result, context ~200-300, full ~500-1000. Start with m9k_search, drill down only when needed. 4x token savings vs loading everything.
Context-aware ranking - results from your current project (×1.5) and current session (×1.2) are automatically promoted. Cross-project results remain visible.
Specialized search
| Tool | Description |
|---|
m9k_file_history | Find past conversations that touched a specific file. |
m9k_errors | Find past solutions for an error message. |
m9k_similar_work | Find past approaches to similar tasks. Prioritizes rich metadata. |
Memory management
| Tool | Description |
|---|
m9k_save | Manually save a memory note for future recall. |
m9k_sessions | List all indexed sessions, optionally filtered by project. |
m9k_info | Show memory index info: corpus size, search pipeline, embedding worker, usage metrics. |
m9k_config | View or update plugin configuration. |
m9k_forget | Permanently remove a chunk from the index. |
m9k_delete_session | Delete a session from the index. |
m9k_ignore_project | Exclude a project from indexing. Future sessions won't be indexed, existing ones optionally purged. |
m9k_unignore_project | Re-enable indexing for a previously ignored project. Purged data is not restored. |
m9k_restart | Restart the MCP server to load fresh code after npm run build. Supports force: true for stuck processes. |
Usage guide
| Tool | Description |
|---|
__USAGE_GUIDE | Phantom tool. Its description teaches Claude the retrieval pattern and available tools. |
Configuration
Zero config by default. Everything is tunable via m9k_config or environment variables.
| Setting | Default | Env var |
|---|
| Database path | ~/.melchizedek/memory.db | M9K_DB_PATH |
| Daemon mode | enabled | M9K_NO_DAEMON=1 to disable |
| Log level | warn | M9K_LOG_LEVEL |
| Embeddings enabled | true | M9K_EMBEDDINGS=false to disable |
| Reranker enabled | true | M9K_RERANKER=false to disable |
See docs/configuration.md for the full settings reference (20+ options, env vars, config file examples).
Enhanced Search
Melchizedek works out of the box with BM25 keyword search. Text embeddings (MiniLM) download automatically on first use for semantic search.
For GPU-accelerated code embeddings (Ollama), cross-encoder reranking (GGUF models), platform-specific setup guides, and the full model reference, see Enhanced Search Setup.
How is this different?
| Melchizedek | claude-historian-mcp | claude-mem | episodic-memory | mcp-memory-service |
|---|
|   |   |   |  |   |
| Philosophy | Search engine - indexes everything, you search | Search engine - scans JSONL on demand | Notebook - AI compresses & saves | Search engine | Notebook - AI decides what to store |
| Indexes raw conversations | Yes (JSONL transcripts) | Yes (direct JSONL read, no persistent index) | Compressed summaries | Yes (JSONL) | No (manual store_memory) |
| Retroactive on install | Yes (backfills all history) | Yes (reads existing files) | No | Yes | No (empty at start) |
| Search | BM25 + vectors + RRF + reranker | TF-IDF + fuzzy matching | FTS5 + ChromaDB | Vectors only | BM25 + vectors |
| Progressive retrieval | 3 layers (search/context/full) | No | No | No | No |
| 100% offline | Yes | Yes | No (needs API for compression) | Yes | Yes |
| Single-file storage | SQLite | None (reads raw JSONL) | SQLite + ChromaDB | SQLite | SQLite-vec |
| Zero config | Yes | Yes | Yes | Yes | Yes |
| MCP tools | 16 | 10 | 4 | 2 | 12 |
| License | MIT | MIT | AGPL-3.0 | MIT | Apache-2.0 |
| Dual embedding (text + code) | Yes (MiniLM + Jina Code) | No | No | No | No |
| Configurable models | Yes (Transformers.js or Ollama) | No | No (Chroma internal) | No (hardcoded) | Yes (ONNX, Ollama, OpenAI, Cloudflare) |
| Reranker | Cross-encoder (ONNX, GGUF, or HTTP) | No | No | No | Quality scorer (not search reranker) |
| Privacy | All local, <private> tag redaction | All local | Sends data to Anthropic API | All local | All local |
| Multi-instance | Singleton daemon - N Claude windows share 1 process (Unix socket / Windows named pipe, local fallback) | N separate processes | Shared HTTP worker (:37777) | N separate processes | Shared HTTP server |
Inspirations
This project stands on the shoulders of others. Key ideas borrowed from:
| Project | What we took | |
|---|
| CASS | RRF hybrid fusion, SHA-256 dedup, auto-fuzzy fallback |  |
| claude-historian-mcp | Specialized MCP tools (file_history, error_solutions) | |
| claude-diary | PreCompact hook (archive before /compact) |  |
Known issues
- Session boost inactive - Claude Code currently sends an empty
session_id in the SessionStart hook stdin payload, preventing the ×1.2 session boost from working. The ×1.5 project boost is unaffected and provides the primary context-aware ranking. Related upstream issues: #13668 (empty transcript_path), #9188 (stale session_id). Melchizedek's session boost code is tested and ready, and will activate automatically when the upstream fix lands.
Privacy
- Zero telemetry. No tracking, no analytics, no network calls (except optional lazy model download).
- Read-only on transcripts. Never writes to
~/.claude/projects/. All data in ~/.melchizedek/.
<private> tag support. Content between <private>...</private> is replaced with [REDACTED] before indexing.- Local-only. Your conversations never leave your machine.
Requirements
- Node.js >= 20
- Claude Code >= 2.0
- macOS, Linux, or Windows
License
MIT
"Without father, without mother, without genealogy, having neither beginning of days nor end of life."
Built by @louis49