Codebase Memory MCP

codebase-memory-mcp: local code intelligence for AI agents via MCP

Understand your repository, from source code to the systems around it. codebase-memory-mcp is an MCP server that connects code, documentation, configuration, and infrastructure in a persistent local knowledge graph. Use it to find an unfamiliar feature, follow a call across services, trace a deployment back to its source, or assess which parts of a project a change could affect.

Give your coding agent structural context through Model Context Protocol (MCP), or query the graph directly from the CLI. The MCP server is the core of the project. Its optional visual companion, CBM Lens, is in open beta (v0.0.1), with a source reader, architecture maps, the Galaxy graph, coverage diagnostics, architecture decisions, and local code chat.

The native C backend exposes 17 MCP tools, parses languages and file formats with vendored grammars, and adds Hybrid LSP type resolution for supported languages. The installer supports 45 automatic or conditional client integrations, including client configuration, skills, agent profiles, and applicable hooks. Indexing and graph queries need no hosted service or API key. Focused graph queries can reduce repeated file reads and token use; see the measured results.

Quick start · Capabilities · Documentation · Infrastructure · Smart CI · Explore CBM Lens · Agent setup · MCP tools

Local processing: Source analysis and graph storage run on your machine. CBM Lens can optionally download a model for browser AI after you enable it; inference stays on the device. The installer writes agent configuration for the clients you select. See Security for release verification and SECURITY.md for reporting issues.

See the graph with CBM Lens (open beta v0.0.1). Folders become nested platforms, files and symbols become selectable blocks, and arrows show indexed relationships. The recording opens src/foundation in the map of this repository, selects arena.c and opens its source. Height can show source size; hotspot gravity reflects static fan-in. Still image.

Galaxy. Explore the code knowledge graph in 3D. The recording follows the outgoing relationships of cbm_arena_alloc one layer further, switches to the hierarchy and shows the two-hop call path to cbm_alloc. Edge pulses show relationship direction; they do not represent live execution. Still: two dependency layers around cbm_max_file_bytes.

Explore. Browse files in an IDE-style workspace, read syntax-highlighted source in Monaco, and keep the code graph alongside it. File impact shows what depends on the open file, and Code details shows the callers and calls of the symbol under the caret. Select code to ask the local chat about it.

The high-resolution GIFs show CBM Lens Beta on 20 October 2026; the still images were captured on 12–13 October. All show public source from this repository. See capture details for each capture's build, indexed scope and recording setup.

Why codebase-memory-mcp

• Find the right code with context: combine symbol, text, and semantic search with callers, dependencies, source snippets, and file outlines. Targeted queries and compact, paged results can reduce token use and repeated file reads; see Performance for scoped measurements.
• Connect documentation to implementation: index document sections, PDF text pages, architecture decisions, and supported references into code. Find the explanation alongside the symbol.
• Follow the system beyond source files: trace supported relationships through Docker, Kubernetes, Helm, Kustomize, Terraform/OpenTofu, Terragrunt, Ansible, scripts, Make, and CI configuration.
• Understand a change before running it: inspect affected symbols, compare indexed snapshots, and find related tests. Experimental Smart CI combines static relationships and per-test coverage for supported C/C++ test harnesses, falling back to broader runs when evidence is insufficient.
• Explore visually with CBM Lens Beta: read source, follow call paths, inspect architecture and coverage gaps, manage architecture decisions, and ask a local model about selected code.
• Equip your coding agents: install sets up supported client configuration, durable guidance, skills, Scout/Verify/Auditor profiles, and applicable context hooks. Support varies by client; see the integration matrix.
• Keep context local and reusable: indexes persist between sessions, eligible active MCP sessions can keep them synchronized, and optional graph artifacts let a team share a baseline.
• Run a native tool on your machine: standard releases include CBM Lens for macOS, Linux, and Windows. The native runtime needs no Docker or language runtime; parser grammars are included.

Quick Start

Install the latest release (macOS / Linux):

curl -fsSL https://raw.githubusercontent.com/DeusData/codebase-memory-mcp/main/install.sh | bash

The standard native release includes CBM Lens. Start it after installation with codebase-memory-mcp daemon start --open --port=9749. The Nix packages and source builds also offer builds without the UI.

Windows (PowerShell):

# 1. Download the installer
Invoke-WebRequest -Uri https://raw.githubusercontent.com/DeusData/codebase-memory-mcp/main/install.ps1 -OutFile install.ps1

# 2. (Optional but recommended) Inspect the script
notepad install.ps1

# 3. Unblock the downloaded file (removes Mark-of-the-Web restriction added by browsers/Invoke-WebRequest)
Unblock-File .\install.ps1

# 4. Run it
.\install.ps1

Note: If you see a script execution policy error, run Set-ExecutionPolicy -Scope Process Bypass first, or invoke with PowerShell -ExecutionPolicy Bypass -File .\install.ps1.

Options: --skip-config (binary only, no agent setup), --dir=<path> (custom location).

Antivirus note: Microsoft Defender may flag a release binary as Trojan:Script/Wacatac.B!ml. This is a known false positive; typically 61 of ~62 engines return clean, and the same detection family hits gh, llama.cpp, Godot and Microsoft's own Go toolchain. See Antivirus False Positives for the evidence, how to verify the artifacts yourself, and how to report it if you think we are wrong.

Restart your coding agent. Say "Index this project": done.

Agent setup: skills, profiles, and hooks

Installation also equips supported coding agents to use the graph in daily work. The native install command detects clients and installs the integration pieces their documented formats support:

Hook augmentation is context-only and fail-open: it does not replace or block the requested tool call. Features vary by client and platform; some clients use durable instructions or a parent-agent handoff instead of hooks or direct subagent MCP access. Codex users review and trust installed hooks through /hooks. See Multi-Agent Support and Sessions, compaction, and subagents for exact support and activation requirements.

Hooks are enabled by default. Run codebase-memory-mcp install --no-hooks to remove CBM-managed hooks while keeping MCP registration and other integration files; the choice persists for later installs and updates. Run codebase-memory-mcp install --hooks to re-enable them, or inspect the current preference with codebase-memory-mcp config get install_hooks.

Session Coordination Daemon

CBM automatically shares one per-account coordination daemon across Claude Code, Codex, OpenCode, and every other configured client. There is no opt-in setting for MCP servers or hook clients: the first daemon-backed CBM session starts it, each session registers its own work, and a session-managed daemon stops after the final session. A daemon started with daemon start remains running until stopped. The daemon owns long-lived background services such as watchers, shared indexing jobs, and the optional UI. Closing one session cancels work owned only by that session, while work still needed by another session continues.

The detached daemon does not depend on an MCP frontend's stderr. It keeps owner-only durable records under the canonical ${CBM_CACHE_DIR}/logs directory (default ~/.cache/codebase-memory-mcp/logs):

Thin frontends still write immediate startup and session-specific errors to their own stderr; MCP JSON-RPC stdout remains clean.

All active CBM processes must run the exact same version, executable build, coordination ABI, and canonical cache root. Equivalent CBM_CACHE_DIR aliases resolve to the same root; a genuinely different root is rejected while any CBM process is active. MCP servers, hooks, one-shot CLI commands, temporary index workers, and the daemon share a crash-safe OS admission barrier; starting an ordinary conflicting process fails before doing work and records an explicit conflict in ${CBM_CACHE_DIR}/logs/daemon-conflicts.ndjson.

The native install and uninstall commands are the deliberate exception to that conflict rule. For installation, download, verification, and private same-filesystem staging finish before activation so a bad candidate never disrupts active work. The native update command prints the installer command that performs the update. Activation then publishes account-wide maintenance intent, asks the daemon and every temporary local operation to cancel, and waits to a finite deadline for all coordinated CBM processes to exit. It holds the admission and lifetime barriers exclusively while changing the active binary, configuration, PATH, or indexes. New CBM work cannot enter during this window. Activation progress and results are recorded in ${CBM_CACHE_DIR}/logs/activation-events.ndjson, and a successful command tells you to restart open coding-agent sessions so they launch the activated build.

Package-manager setup (npm, PyPI, or Go) verifies and caches the native executable for that package. It does not replace the active native installation and therefore does not stop running CBM sessions. When that cached binary is executed, it still enters the same exact-build admission barrier. The shell and PowerShell installers invoke the verified candidate's native install command, so they do receive the full account-wide activation guarantee.

The ordinary cli mode runs one command locally, but it is not disconnected from the daemon above: it connects to the shared coordination daemon (starting one if none is already running) for that same admission barrier plus per-project locks on graph mutations. Its connection is a cli_session: it does not register a project watcher or open a browser, and it holds the admission lease only for the command's lifetime. The shared daemon may serve Lens according to its UI configuration and available assets. If the command's own connection is what started the daemon, that daemon exits again once the command closes and no other session is attached; if a daemon was already running, the command simply joins and leaves it exactly as found. While the command is running, a temporary monitor separately lets activation cancel that operation and its supervised worker safely; the monitor exits with the command and never becomes a standing daemon. See CLI Mode for details.

CBM Lens Beta: code visualization and source navigation

CBM Lens is an optional visual companion to the MCP server, currently in open beta (v0.0.1). Standard native releases include its browser interface, so you can launch Lens directly after installation; UI-enabled source builds include it too. It builds on CodeAtlasWeb by Bernhard Jackiewicz (design and tracking in #1964). Lens is served on loopback. Browser AI downloads its optional model only after you enable it; inference stays on-device. Each panel names where its facts come from, and what the index did not record is shown as a gap. Start the local server:

codebase-memory-mcp daemon start --open --port=9749

The browser opens at http://127.0.0.1:9749. A permanent daemon keeps the UI available after the command exits. Use daemon status to inspect it and daemon stop when you are finished. For an MCP session, --ui=true --port=9749 enables the same shared UI. Active clients must use the same executable build and cache directory.

Open your first repository

1. Open the project menu and choose Add project index. You can also use Alt+P.
2. Choose a local repository folder and name the index. Files stay in place.
3. Start indexing and follow its reported status. You can close the dialog while it runs and reopen its activity from the project menu.
4. Open the indexed project. Start with Architecture for an overview or Explore to read a file.

To bookmark a view, use ?project=<name>&workspace=architecture. Other workspace values are explore, galaxy, adr, coverage, and system.

Architecture views

• Overview: move through source folders and files on a 3D map. Choose source-size or uniform height, language or kind colors, and relationship filters. Switch to Entry points to follow a static call graph from a starting symbol.
• Routes: switch between the service map and endpoint connections. Deployment metadata and indexed route evidence are shown separately; unresolved registrations remain visible.
• Hotspots: inspect symbols using measured signals such as fan-in and complexity. Gravity wells help locate frequently referenced areas. They are not a code-quality score.
• System structure: inspect component dependencies, expand groups, isolate cycles, and follow connections back to source evidence.
• Behavior: choose a source and a reachable destination to inspect static call paths and their source statements. These paths show possible relationships, not a recorded execution order. Runtime observations require separately ingested traces.

Drag a 3D view to orbit, scroll to zoom, and select a node or edge to inspect it. Edge colors distinguish relationships, and pulses indicate their direction. Reduced-motion preferences pause the pulses. Large views show their limits and omitted counts. A missing edge can reflect an indexing or display limit, so check Coverage and the source before drawing conclusions.

Chat with your codebase locally

Open Chat with the panel button at the top right to ask about the code you are looking at. In Explore it uses the open file or the exact text you have selected; in Galaxy it uses the selected node and its loaded neighbors. You can also attach graph evidence through Add context.

1. Click the robot icon at the top right to open the agent configuration.
2. Choose a local model. The default Qwen2.5 Coder 0.5B downloads about 567 MB; Qwen3 0.6B, LFM2.5 1.2B and Qwen3.5 2B are larger options. All need WebGPU with shader-f16 support.
3. Click Download & load. Model files come from Hugging Face; inference runs in your browser, with no hosted chat API or API key. A model that is already in the browser cache loads with Load model (cached, no download).
4. Ask a question. The composer shows the file or selection that will accompany it. Select a smaller range when you want to focus the answer.

Questions about callers and callees, such as "Who calls cbm_pipeline_run?", are answered from the loaded graph without the model, and the answer says so. When you select a symbol, the chat lists its indexed facts and the lines of its code, and the model adds one sentence; that sentence is left out when it claims something the source does not show. Text written by the model is labelled as such.

The recording asks who calls arena_grow and what it calls, with both answers listed directly from the indexed graph beside the selected symbol. Still image of a model explanation and graph answer.

The chat history is kept for 24 hours in this browser, per project. Each new message uses the source currently open in the reader; earlier source snapshots are not silently accumulated, and messages about another file or selection are not sent along. If a prompt is too long for the model, older messages are left out first; if it still does not fit, CBM Lens asks you to select less code instead of cutting the code. This chat explains the context you give it; it cannot edit files or run tools. Check its answers against the source. The small default model words things loosely, especially in languages other than English.

Search

Cmd+K or Ctrl+K opens the Galaxy search. It finds symbols, files and folders by name or path in the whole index, also nodes that are not loaded yet. For callers and callees, ask in the chat; the answer is listed from the graph.

Architecture decisions

The ADR workspace keeps an unsaved draft per project in this browser tab. It checks whether the stored document changed before saving, but the API does not provide an atomic document lock. The editor accepts up to 8,000 UTF-8 bytes. Saving changes the indexed decision document, not a file in your repository.

VITE_EXPERIMENTAL_AGENTS=true scripts/build.sh --with-ui

For troubleshooting, open System logs. Frontend errors and failed requests are recorded locally. GET /api/ui-log reads frontend entries from the daemon's SQLite journal; ${CBM_CACHE_DIR}/logs/ui.log is also retained as a rotating JSONL export. See the frontend README for log scope, model setup, and development details.

Auto-Index

Enable automatic indexing on MCP session start:

codebase-memory-mcp config set auto_index true

auto_index is off by default. When enabled, new projects are indexed automatically on first connection. The configurable file limit is config set auto_index_limit 50000. Previously indexed projects can be watched through auto_watch (on by default), subject to its global setting and session ownership.

Each initialized, long-lived MCP session can register its root project when it connects and any target from a successful index_repository call, including custom project names and roots in another worktree. While auto_watch is enabled, these watches belong to the registering sessions and remain while at least one owning session is connected; closing the last owner removes the watch. Under a daemon started with daemon start a watch outlives its last owning session: the project stays watched and is re-indexed in the background when it changes, until that daemon stops, the project is deleted, its directory disappears, or auto_watch is set to false. An async index registers its target only after success and while its requesting session remains connected. CLI indexing and failed MCP indexes do not register watches. Global auto_watch controls registration and removes all watches on the next refresh or registration request when set to false. index_status reports this in its watch object: watched, and either the poll cadence and last scan time or the reason it is not watched.

Watcher registration is controlled globally by auto_watch (default true). On the next refresh or registration request, true allows MCP sessions to register their root on connect and their successful index_repository targets; false removes all watches. CLI indexing and failed MCP indexes do not add watches.

To turn the watcher off entirely, set config set watcher_enabled false (default true): the background poll thread never starts and no project is registered, while auto_index and manual index_repository keep working. Unlike auto_watch, which takes effect on the next refresh or registration request, watcher_enabled is read once when the background daemon starts, so run codebase-memory-mcp daemon stop after changing it; reconnecting your MCP client alone will not restart the daemon. See docs/CONFIGURATION.md.

The watcher follows git projects only by default: a project indexed from a directory that is not a git repository is not watched and stays at its last index until you run index_repository again. To have such roots polled too, set config set watch_non_git true (default false, read when the daemon starts): they are then checked on the same cadence with a file-tree scan that uses the indexer's own ignore rules.

Linked git worktrees are indexed as their own projects by default. Set config set ignore_worktrees true to skip them on the automatic paths — useful when short-lived git worktree add checkouts would otherwise each leave behind a permanent index of the same repository. An explicit index_repository call on a worktree is then refused unless you pass index_worktree=true. See docs/CONFIGURATION.md.

Keeping Up to Date

Updates run from the install script on every platform, not from inside the running binary. codebase-memory-mcp update validates your flags and then prints the exact command to run:

# macOS / Linux
bash "<install-dir>/install.sh"

# Windows
powershell -File "<install-dir>\install.ps1"

The install script is placed next to the binary at install time, so the printed path resolves beside the executable. It is idempotent, so re-running it is the update: it stops the daemon, retires the running binary, installs the new one, and cleans up.

Why it works this way. On Windows it is a hard requirement; a running executable cannot replace its own image, so the swap has to happen from a process that is not the binary being replaced. On macOS and Linux it is a deliberate choice: an in-process updater is structurally a downloader (fetch an archive, verify it, unpack it, mark a file executable, run it), and shipping that composite in every binary to serve a command most people run a handful of times is a poor trade. The release archives now carry no download URLs at all, and cbm makes no network request of its own accord: it does not check for new versions in the background, and nothing phones home. You find out about releases from the install script, your package manager, or GitHub.

If PowerShell refuses to run the script because the file came from the internet, Unblock-File it first.

Installed through npm or pip? Update with your package manager on every platform (npm install -g codebase-memory-mcp@latest / pip install -U codebase-memory-mcp).

Uninstall

codebase-memory-mcp uninstall

Removes owned agent config entries, skills, hooks, instructions, and the installed binary. Existing graph indexes are listed and kept by default. -y/--yes, -n/--no, and noninteractive input keep them unless --delete-indexes is explicitly given. An interactive terminal without that flag is asked separately; the default answer is to keep them.

codebase-memory-mcp uninstall -y --delete-indexes   # also delete every project index
codebase-memory-mcp uninstall --dry-run --delete-indexes   # preview; change nothing

--delete-indexes is explicit consent and takes precedence over --no; --dry-run always preserves the files. When indexes are kept, uninstall prints their cache directory (${CBM_CACHE_DIR:-~/.cache/codebase-memory-mcp}) and how to remove them.

The install script placed beside the binary is reported, not deleted: uninstall prints its path and the rm command for it. It is left alone on purpose: it may be your own copy, a symlink into a checkout, or managed by a package manager, and an uninstaller should not delete a file it cannot prove it owns.

Features

Graph & analysis

• Architecture overview: get_architecture returns a compact summary by default. Request specific aspects for routes, hotspots, dependencies, clusters, or cycles. system_structure provides the projection used by CBM Lens and must be requested on its own.
• Architecture Decision Records: manage_adr persists the project's decision record across sessions; indexing also extracts supported ADR metadata and supersession from documentation files
• Louvain community detection: Discovers functional modules by clustering call edges
• Change impact: detect_changes maps uncommitted changes to affected symbols with risk classification and can report test impact with scope: "tests"; compare_graphs compares indexed snapshots
• Runtime observations: ingest_traces adds observed call relationships from separately collected traces alongside static analysis; static call paths alone do not show what ran
• Call graph: Resolves function calls across files and packages (import-aware, type-inferred)
• Dead code candidates: find functions with no indexed callers, excluding entry points. Check dynamic dispatch, coverage gaps, and framework conventions before removing code.
• Cypher-like queries: MATCH (f:Function)-[:CALLS]->(g) WHERE f.name = 'main' RETURN g.name

Search

• Semantic search (the semantic_query parameter of search_graph, not a separate tool): vector search across the entire graph, powered by bundled Nomic nomic-embed-code embeddings (40K tokens, 768d int8) compiled into the binary; no API key, no Ollama, no Docker. 11-signal combined scoring (TF-IDF, RRI, API/Type/Decorator signatures, AST profiles, data flow, Halstead-lite, MinHash, module proximity, graph diffusion).
• BM25 full-text search via SQLite FTS5 with cbm_camel_split tokenizer (camelCase / snake_case aware)
• Structural search (search_graph): regex name patterns, label filters, min/max degree, file scoping
• Code search (search_code): graph-augmented grep over indexed files only

Documentation connected to code

Find the explanation behind a symbol and follow supported references back to its implementation. Documentation participates in the graph alongside source files:

• Markdown, reStructuredText, and AsciiDoc become navigable document sections; PDFs with text layers become searchable text pages. PDF extraction does not perform OCR.
• Document-to-code references and supported language doc-comment references create MENTIONS relationships when the target can be resolved.
• Architecture decision records contribute metadata such as status, deciders, and supersession, so decisions can be explored with the code they describe.
• Supported diagrams and OpenAPI descriptions contribute structured entities. Extraction and reference resolution differ by format; not every textual mention becomes a graph edge.

Use graph and text search to locate the relevant section, follow its recorded relationships, and open the source evidence. Check check_index_coverage before treating a missing result as proof that the repository has no such documentation or reference.

Infrastructure and deployment

Ask "What deploys this service?", "Which image runs it?"

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