memex — temporal knowledge graph memory for AI coding agents

Persistent memory and codebase context for AI coding agents, served over MCP. A bitemporal knowledge graph of your repository — modules, symbols, decisions, problems — for Claude Code, Cursor, Codex, Gemini CLI, and any MCP-compatible agent.

A daemon and MCP server that turns every commit and every file change into structured graph state: modules, symbols, decisions, problems, lockfile facts. Sessions stop starting blind. Agents stop re-discovering the same refactor every time you /clear.

flowchart LR
    A[Your repository<br/>files + git] --> B[memex watcher<br/>tree-sitter + Gemini]
    B --> C[Neo4j graph<br/>bitemporal facts]
    C --> D[MCP server<br/>stdio / HTTP]
    D --> E[AI agent<br/>Claude · Cursor · Codex · Gemini CLI]
    E -.->|writes decisions back| C

    style B fill:#cfe8ff,stroke:#0066cc,color:#000
    style C fill:#fff4cf,stroke:#cc9900,color:#000
    style E fill:#d4f5d4,stroke:#2d8f2d,color:#000

Install

Via Claude Code marketplace

/plugin marketplace add STiFLeR7/claude-plugins
/plugin install memex-mcp@stifler-marketplace

Restart your Claude Code session.

Manual

docker compose -f docker/docker-compose.yml up -d
cat > .env <<EOF
NEO4J_URI=bolt://localhost:7687
NEO4J_USER=neo4j
NEO4J_PASSWORD=memex-local
GEMINI_API_KEY=your-key-here
EOF
npx stifler-memex-mcp init --repo .
npx stifler-memex-mcp watch --repo .
npx stifler-memex-mcp serve --repo .

| Channel | Command | |---|---| | Claude Code marketplace | /plugin install memex-mcp@stifler-marketplace | | npx (no install) | npx stifler-memex-mcp <cmd> | | uv | uv add memex-mcp | | pip | pip install memex-mcp | | source | git clone github.com/STiFLeR7/memex && uv sync |

Self-hosted team deployment

For a shared team setup (one Neo4j + one memex-server, auth on by default, Neo4j's ports never exposed to the host):

bash docker/bootstrap-team-env.sh
docker compose -f docker/docker-compose.team.yml up -d

See docker/TEAM-DEPLOY.md for the full flow, capturing the initial admin key, and the down -v footgun to avoid.

At a glance

| Property | Value | |---|---| | Output | A Neo4j graph populated continuously from your repo | | Storage | Neo4j via Graphiti. Bitemporal — every edge has created_at and optional expired_at | | Survives | /clear, terminal crashes, machine restarts, teammate handoffs | | Hands off to | Claude Code, Cursor, Codex, Gemini CLI, any MCP client | | Granularity | Scales from 50 to 5000+ modules via hierarchical Leiden clusters | | Synthesis | Gemini Flash distills commits into Decision nodes; Pro for grounded synthesis | | Confidence | Computed at query time. Two-regime decay (validated half-life ~139d, unvalidated stale at 30d) | | Write governance | Per-node-type ACL, intent-confirmation on agent writes, explicit corroborates / supersedes semantics | | Tests | 333 passing, ~93% coverage |

The lifecycle

flowchart TD
    Init[memex init<br/>extract baseline] --> Watch[memex watch<br/>daemon + git hooks]
    Watch -->|commit| Extract[tree-sitter extract<br/>symbols, imports, lockfile]
    Extract --> Synth[Gemini Flash<br/>diff → Decision nodes]
    Synth --> Write[Graphiti add_episode<br/>+ post-hoc bitemporal SET]
    Write --> Decay[Scheduler<br/>nightly confidence decay]
    Decay -->|stale edges| Archive[expired_at = now]

    Serve[memex serve<br/>MCP stdio/HTTP] -.->|reads| Write
    Agent[AI agent] -->|14 MCP tools| Serve
    Serve -->|record_decision / record_problem| Write

    Cluster[memex cluster<br/>Leiden over hybrid edges] -.->|every N commits| Write

    style Init fill:#e8f4ff,color:#000
    style Watch fill:#fff4cf,color:#000
    style Synth fill:#ffe0cc,color:#000
    style Serve fill:#d4f5d4,color:#000

MCP tools

14 tools — eight read, four write, two analytic.

Read

| Tool | When | |---|---| | get_project_context | Session start. Returns a cluster-level briefing under 1500 tokens regardless of repo size | | get_symbol_context | Before editing a function or class. Returns callers, callees, linked decisions | | get_recent_decisions | Last N days of architectural decisions, optionally module-scoped | | get_open_problems | Active bugs and tech debt, sorted by severity | | search_context | Hybrid search: semantic × keyword × graph traversal × RRF merge | | get_stale_context | Edges whose composite confidence dropped below threshold | | explain_change | Given a commit SHA, cross-references the diff with linked Decision/Problem nodes and asks Gemini Pro for a grounded explanation | | predict_impact | Given a file path, returns a ranked list of modules likely affected based on graph coupling (no LLM call) |

Write

| Tool | When | |---|---| | record_decision | After making a technical choice. Supports corroborates (reinforce) and supersedes (replace) | | record_problem | When discovering a bug or piece of tech debt | | resolve_problem | When a tracked problem is fixed | | invalidate_edge | When a stored fact is no longer true |

Bitemporal confidence

Confidence is not a stored number that mutates. It is computed at query time from base_confidence, validation status, time since last reinforcement, and access count.

flowchart LR
    Edge[Edge created<br/>base_confidence] --> Q{Validated by<br/>a human?}
    Q -->|yes| Slow[Slow regime<br/>half-life ~139d]
    Q -->|no| Fast[Fast regime<br/>stale at exactly 30d]
    Slow --> Score[Composite score<br/>conf × recency × rehearsal]
    Fast --> Score
    Score -->|below floor| Stale[get_stale_context surfaces it]
    Score -->|access| Bump[last_reinforced_at updated]
    Bump --> Score

    style Slow fill:#d4f5d4,color:#000
    style Fast fill:#ffd4d4,color:#000

| Property | Value | |---|---| | Validated half-life | ~139 days | | Unvalidated stale threshold | 30 days (composite < 0.3) | | Recency τ | 90 days (exponential decay) | | Composite formula | conf × recency × (1 + rehearsal_w × log(1 + access_count)) | | Conflict similarity threshold | 0.4 (below this + overlapping validity = conflict) | | Intent-confirmation threshold | 0.85 (MCP write similarity check) |

Hierarchical clusters

memex cluster runs hierarchical Leiden over a hybrid edge graph:

| Edge type | Weight | |---|---| | Directory co-location | 1.0 | | Module imports | 2.0 | | Symbol calls | log(1 + calls) |

| Property | Value | |---|---| | Algorithm | graspologic.partition.hierarchical_leiden with fixed seed | | Naming | TF-IDF top-3 over module docstrings + symbol names, parent-dir fallback | | ID pinning | Jaccard ≥ 0.5 across reruns (cluster names stay stable through renames) | | User overrides | .memex/clusters.yaml — any assignment can be locked | | Context budget | get_project_context stays under 1500 tokens whether your repo has 50 or 5000 modules |

Measure Your Savings

memex tracks token reduction metrics and human review actions locally in a SQLite database (~/.config/memex/telemetry.db).

You can query your savings at any time using the CLI:

memex stats

Or view the raw JSON payload:

memex stats --json

Or target a specific repository scope:

memex stats --repo /path/to/repo

This returns an aggregation of:

• Period Summaries: Calls, tokens returned, naive tokens (size of files requested), tokens saved, and token reduction percentage across today, last 7 days, last 30 days, and lifetime.
• Top Tools: The most valuable tools sorted by total tokens saved.
• Agent Clients: Active agents (Claude Code, Gemini CLI, Cursor, Codex) and their token saving distribution.
• Validation Health: Total validated, unvalidated, and corroborated nodes, along with the elapsed days since the last review.

The same statistics are exposed via the HTTP MCP transport:

GET /stats?repo=/path/to/repo
Authorization: Bearer <your-key>

Connect your agent

Marketplace install above does this for you. Manual wiring in .claude/settings.json:

{
  "mcpServers": {
    "memex": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "stifler-memex-mcp", "serve", "--repo", "."]
    }
  }
}

Add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "memex": {
      "command": "npx",
      "args": ["-y", "stifler-memex-mcp", "serve", "--repo", "."]
    }
  }
}

Add to ~/.gemini/settings.json:

{
  "mcpServers": {
    "memex": {
      "command": "npx",
      "args": ["-y", "stifler-memex-mcp", "serve", "--repo", "."]
    }
  }
}

Add to ~/.codex/config.toml:

[mcp_servers.memex]
command = "npx"
args = ["-y", "stifler-memex-mcp", "serve", "--repo", "."]

memex can back Claude's native memory tool — agents read from a per-session graph projection plus a writable scratch zone.

memex memory-tool serve --repo .                     # in-process
memex memory-tool serve --repo . --transport http    # FastAPI on :7464

from memex.memory_tool import MemexAsyncMemoryTool
memory_tool = MemexAsyncMemoryTool(repo_root=".")
client.beta.messages.run_tools(..., tools=[memory_tool])

Operating principles

| # | Principle | The bet | |---|---|---| | 1 | Bitemporal, never destructive | Edges are expired, not deleted. WHERE r.expired_at IS NULL filters live state | | 2 | Confidence is computed, not stored | Mutating a number invites silent drift. Recompute every read | | 3 | Two regimes for decay | Validated facts decay slowly; unvalidated facts must earn their place by being accessed | | 4 | Human in the loop | memex review queues lowest-confidence Decision nodes for explicit validation | | 5 | Write governance | Per-node-type ACL. Decision.policy = open, Module.policy = locked. Intent-confirmation on similar-content writes | | 6 | Tokens are budgeted | get_project_context stays under 1500 tokens at any repo size via Leiden clusters | | 7 | Synthesis only on commits | The watcher batches by debounce window. Gemini Flash is not in the hot path of a tool call | | 8 | Pro for synthesis, Flash for extraction | explain_change uses Pro because grounding matters. Everything else uses Flash | | 9 | Multi-repo aware | One watcher + one MCP server can manage hundreds of repos. --repo switches scope | | 10 | Local-first | Neo4j runs in your Docker. Gemini is the only outbound call, and only on commits |

When to use memex

| Use it when | Skip it when | |---|---| | Multi-week or multi-month project | One-shot script, throwaway prototype | | You work across multiple agents (Claude, Cursor, Codex) and want shared context | You only ever pair with one agent on one task | | Architectural decisions are made over time and need to be remembered | The whole project fits in a single 200k-token context window | | You want to query "what did we decide about X" from any session | Your repo is already small enough to paste into the prompt | | Multiple developers using AI agents on the same codebase | Solo work where you never /clear |

Project structure

memex/
├── memex/
│   ├── extractor/        tree-sitter + lockfile parsers
│   ├── graph/            Neo4j writes, confidence, archive, cluster engine
│   ├── synthesizer/      Gemini Flash → Decision nodes
│   ├── mcp_server/       14 MCP tools (read + write + analytic)
│   ├── memory_tool/      Anthropic memory_20250818 adapter
│   ├── watcher/          daemon + git hooks
│   └── cli.py            init / watch / serve / review / graph / cluster
├── tests/                333 passing, ~93% coverage
├── docker/               Neo4j compose
├── npm/                  npx wrapper (publishes as stifler-memex-mcp)
└── Dockerfile            introspection-only image for MCP directory sandboxes

Commands

| Command | What it does | |---|---| | memex init | Extract baseline graph state, run first cluster pass | | memex watch | Daemon that listens for file + git events and writes to Neo4j | | memex serve | Run the MCP server (stdio, HTTP, or both) | | memex review | TUI that walks lowest-confidence decisions for human validation | | memex graph --output graph.html | Self-contained D3 force layout with cluster overlays | | memex cluster [--rerun] [--dry-run] | Run Leiden over the hybrid edge graph; pin cluster IDs by Jaccard ≥ 0.5 | | memex memory-tool serve | Back Anthropic's memory_20250818 tool with a graph projection | | memex stats [--json] [--repo <path>] | Show context token savings and telemetry stats |

License

MIT. See LICENSE.

Author

Hill Patel (@STiFLeR7)

Core Contributors & Maintainers

• Hill Patel (@STiFLeR7) — architect, maintainer
• Nirvaan Lagishetty (@Nirvaan05) — lead contributor, maintainer

Contributing

Open an issue or PR. uv sync --all-extras && uv run pytest tests/ is all the setup you need to run the suite. Version bumps must update both pyproject.toml and npm/package.json and they must agree.

Vannevar Bush, 1945: "Consider a future device for individual use, which is a sort of mechanized private file and library. It needs a name, and to coin one at random, memex will do."