code-kb

Interactive Showcase & Benchmarks: https://anortham.github.io/code-kb/

code-kb is a fast, lightweight code-intelligence engine and Model Context Protocol (MCP) server designed specifically for AI coding agents.

Backed by the rich AST fact tables produced by julie-extractors, code-kb provides progressive disclosure, semantic symbol navigation, and surgical context slicing—enabling agents to navigate, understand, and edit codebases with 80–90% fewer tokens without burning context on full file reads or noisy text grep.

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Why code-kb?

Traditional AI coding agents burn massive amounts of context loading entire source files into their prompt windows just to inspect a single type signature or implementation detail.

code-kb solves this with a progressive disclosure architecture:

1. Repository Orientation (codebase_outline): Understand directory structures and key exports in ~200 tokens.
2. File Skeletons (file_skeleton): Inspect function signatures, types, traits, and docstrings with implementation bodies stripped.
3. Symbol Lookup & Discovery (lookup_symbol / search_symbols): Instant exact/prefix identifier lookups and conceptual FTS5 search across all symbols.
4. Surgical Symbol Context (get_symbol_context): In a single turn, fetch a target function's body along with its callee signatures, parameter types, and associated unit tests.
5. Atomic AST Edits (replace_symbol_body): Replace symbol implementations atomically with pre-flight syntax validation by julie-extract for every language it parses, then re-index immediately.

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Key Principles

• Sub-15MB Retained Memory: Written in Rust, zero heavy runtimes (no web dashboard, no GPU models), retained process memory stays below 15 MB. The plugin launcher is a small Node script that starts the native binary and then only waits on it.
• Sub-5ms Query Latency: Direct SQLite queries in WAL mode with zero in-memory heap bloat.
• Zero Workspace Parameters: Pure semantic tool calling (lookup_symbol(query="...")). The agent is never burdened with workspace_id, repo_path, or path confusion.
• CLI-First Parity: Every MCP tool has an exact 1:1 CLI command for instantaneous terminal verification and dogfooding.
• Continuous 3-Tier Sync: Tool-driven updates, JIT staleness guards before reads, and a debounced background watcher with a Git storm circuit breaker.

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Install

Install the plugin for your agent. The plugin ships a small Node.js launcher. On the first run it downloads the matching code-kb release archive for your platform, verifies its SHA-256, and unpacks code-kb and julie-extract into ~/.code-kb/dist/<version>/. Later runs start instantly. Nothing else to download or put on PATH.

Requirements:

• Node.js 18 or newer on PATH (the launcher is a Node script; the server itself is a native binary).
• Windows 10 build 17063 or newer (the launcher unpacks with the built-in tar.exe).

Claude Code

/plugin marketplace add anortham/code-kb

/plugin install code-kb@code-kb

(Send as two separate prompts.) The plugin registers the MCP server, the progressive disclosure skill, a /code-kb:telemetry command for usage and token-savings reports, and SessionStart and SubagentStart hooks that inject routing instructions.

Codex

codex plugin marketplace add anortham/code-kb
codex plugin add code-kb@code-kb

Run codex, open /hooks, and trust the two code-kb hooks.

To update, refresh the marketplace snapshot first. codex plugin remove followed by codex plugin add reinstalls the version already in the snapshot:

codex plugin marketplace upgrade
codex plugin remove code-kb@code-kb
codex plugin add code-kb@code-kb

Antigravity CLI (AGY)

agy plugin install https://github.com/anortham/code-kb

The plugin registers the MCP server and a PreInvocation hook. Antigravity has no SessionStart hook, so routing directives arrive per turn through injectSteps.

Grok CLI

grok plugin install anortham/code-kb --trust

First Run & Automatic Indexing

You do not need to run code-kb scan by hand. The first code-kb tool call or CLI command in a repository creates <workspace>/.code-kb/artifact.db and runs the initial scan. A git worktree copies its parent repository's index instead of scanning again. Files that changed while no session ran, for example after a branch switch, are reconciled before the first answer. Pre-index a large repository before a session with:

code-kb scan

Launcher environment variables:

Variable	Effect
CODE_KB_HOME	Directory that holds dist/ (default ~/.code-kb).
CODE_KB_VERSION	Release version to fetch instead of the plugin's own version.
CODE_KB_BIN	Run this binary and skip the download entirely (local builds).

Two overrides need no environment variable, which matters in harnesses that do not pass the environment to MCP servers (Codex):

• A binary or symlink at ~/.code-kb/bin/code-kb (code-kb.exe on Windows) runs instead of any download, in every harness. For development: ln -s /path/to/code-kb/target/release/code-kb ~/.code-kb/bin/code-kb.
• A plugin installed from a source checkout runs that checkout's target/release/code-kb when it exists.

With either in place, cargo build --release plus a session restart is the whole development loop.

Uninstall

Harness	Command / Action
Claude Code	/plugin remove code-kb
Codex	codex plugin remove code-kb@code-kb
Antigravity (AGY)	agy plugin uninstall code-kb
Grok CLI	grok plugin uninstall code-kb

Delete ~/.code-kb/dist to remove the downloaded binaries. Each workspace keeps its index in <workspace>/.code-kb/; delete that directory to remove the index.

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Manual Configuration

Use this path for harnesses without a plugin manager, or when you would rather manage the binary yourself.

Step 1: Get the Binaries

• GitHub Releases: download the archive for your platform from GitHub Releases:

  • Linux x86_64 (.tar.gz)
  • macOS Apple Silicon (.tar.gz)
  • macOS Intel (.tar.gz)
  • Windows x86_64 (.zip)

  Unpack it and put both binaries on your PATH (for example ~/.local/bin, /usr/local/bin, or C:\tools). code-kb and julie-extract are packaged side by side, and code-kb finds julie-extract next to its own executable.

• Cargo:

  cargo binstall code-kb-cli
  # or
  cargo install code-kb-cli
  

  Cargo installs code-kb only. Download the pinned julie-extract from the julie-extractors releases (version in scripts/julie-pins.json) and put it on your PATH or set JULIE_EXTRACT_BIN.

• Verify:

  code-kb --version
  

Step 2: Register the MCP Server

Every harness runs the same command: code-kb serve. Hooks run code-kb hook <Event>.

How code-kb Finds Your Workspace

Tools never take a workspace parameter. The server binds a workspace in three steps, and each later step replaces the earlier one:

1. At start: --root <path> on the serve command, or, without it, the directory the process starts in, searched upward for .git or a project marker.
2. At handshake: the roots the host sends in the MCP initialize request, if any.
3. At each tool call: an absolute path inside a repository in any file_path or path argument.

Terminal harnesses (Claude Code, Codex, AGY, Grok CLI, Copilot CLI, Pi, Swival, Zed) start the server in the project directory, so code-kb serve alone is enough.

GUI apps (Cursor, Windsurf, the Antigravity IDE, Visual Studio, VS Code, Claude Desktop) start the server from their own install directory, not from your project. For these apps, put the MCP config inside the project and pass --root with the absolute path of the project:

"args": ["serve", "--root", "/absolute/path/to/project"]

Without --root, the first tool call in a GUI app fails with Database artifact not found ... configure code-kb with '--root <repo-path>'. That error is the signal to add the flag. A tool call with an absolute path inside a repository also binds the server, so a session can recover, but --root removes the guesswork.

Claude Code (without the plugin)

claude mcp add --scope user code-kb -- code-kb serve

Codex (without the plugin)

In ~/.codex/config.toml:

[mcp_servers.code-kb]
command = "code-kb"
args = ["serve"]

Antigravity CLI (without the plugin)

agy mcp add code-kb code-kb serve

Global config (~/.gemini/config/mcp_config.json) with "eager": true. The AGY CLI starts the server in the project directory. The Antigravity IDE starts it from its own install directory, so add --root when you use the IDE:

{
  "mcpServers": {
    "code-kb": {
      "command": "code-kb",
      "args": ["serve", "--root", "/absolute/path/to/project"],
      "disabled": false,
      "eager": true,
      "force_all_tools_eager": true
    }
  }
}

Lifecycle hook configuration (~/.gemini/config/hooks.json):

{
  "code-kb": {
    "PreInvocation": [
      {
        "command": "code-kb hook PreInvocation",
        "timeout": 10,
        "type": "command"
      }
    ]
  }
}

Progressive disclosure skill linking:

ln -sf /path/to/code-kb/skills/code-kb ~/.gemini/config/skills/code-kb

Grok CLI (without the plugin)

Project-level .mcp.json:

{
  "mcpServers": {
    "code-kb": {
      "command": "code-kb",
      "args": ["serve"]
    }
  }
}

Cursor

In .cursor/mcp.json at the repository root. Cursor is a GUI app, so pass --root:

{
  "mcpServers": {
    "code-kb": {
      "command": "code-kb",
      "args": ["serve", "--root", "/absolute/path/to/project"]
    }
  }
}

OpenCode

Add to opencode.json in the project:

{
  "mcpServers": {
    "code-kb": {
      "command": "code-kb",
      "args": ["serve", "--root", "/absolute/path/to/project"]
    }
  }
}

Claude Desktop

Claude Desktop has one global config and no project directory, so --root pins one project. Add to claude_desktop_config.json (%APPDATA%\Claude\claude_desktop_config.json on Windows, ~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "code-kb": {
      "command": "code-kb",
      "args": ["serve", "--root", "/absolute/path/to/project"]
    }
  }
}

Other GUI Apps (Windsurf, Visual Studio, VS Code)

Use the app's project-level MCP config file and the same arguments: ["serve", "--root", "/absolute/path/to/project"]. On Windows write the path with forward slashes, for example C:/source/project.

GitHub Copilot CLI & Terminal Agents

Terminal harnesses (Copilot CLI, Pi, Swival, Zed) start the server in the project directory: configure the MCP server to run code-kb serve with no --root.

To remove a manual configuration, delete the code-kb entry from the harness config (claude mcp remove code-kb, agy mcp remove code-kb, or edit the file) and delete the binaries from your PATH.

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MCP Tool Catalog

Tool	Purpose	Key Parameters	Aliases
codebase_outline	High-level architectural orientation of directory layout & symbols.	path (opt), depth (opt, default 2)	dir, subpath
file_skeleton	File outline with function & method bodies stripped (80–90% token savings); a directory returns its outline.	file_path (req)	file, path
lookup_symbol	Fast identifier lookup (exact name or prefix) across repo or scoped path.	query (req), path (opt), kind (opt), is_test (opt), limit (opt)	name, q
search_symbols	Conceptual BM25 full-text search over symbol signatures & docstrings.	query (req), path (opt), kind (opt), limit (opt)	name, q
get_symbol_body	Slices the exact implementation body of a symbol from disk.	symbol_name (req), file_path (opt)	symbol, name, path
get_symbol_context	Surgical bundle: target body + callee signatures + parameter types + tests.	symbol_name (req), file_path (opt), include_external (opt, def: false)	symbol, name, path
find_references	Callers or callees of a symbol, matched by name from AST call sites and ranked by same file, same directory, then receiver type; callers also include type usages and member accesses (filters external stdlib noise; qualify overloaded names).	symbol_name (req), file_path (opt), direction ("callers" | "callees", def: callers), include_external (opt, def: false)	symbol, name, file, path
blast_radius	Multi-hop reverse reachability (CTEs) & targeted test prediction.	symbol (opt), file (opt), depth (opt, def: 2), limit (opt)	name, path, impact
find_structural_facts	Queries framework facts (routes, SQL queries, config keys, tables). Lists all categories when omitted.	category (opt), path (opt), limit (opt)	cat, kind, type, file, file_path
replace_symbol_body	Atomically replaces a symbol's implementation; julie-extract check validates the syntax for every language it parses (about 40), other paths report validation skipped.	symbol_name (req), file_path (req), new_body (req), expected_body_hash (opt)	symbol, file, body, code
telemetry_summary	Token savings, call counts, and error rates from ~/.code-kb/telemetry.db, across all workspaces or scoped to the current one.	time_window (opt, def: all), workspace_only (opt, def: false), json (opt)	since, window

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CLI Commands (Direct Terminal Usage)

Every MCP capability can be executed directly from your terminal with 1:1 parity:

# Architectural outline of current repo (depth 2)
code-kb outline

# Skeleton of a specific file (implementation bodies stripped)
code-kb skeleton src/main.rs

# Lookup symbols by exact name or prefix (alias: code-kb symbol)
code-kb lookup Workspace --kind struct --path crates/code-kb-core

# Conceptual BM25 full-text search across docstrings and signatures
code-kb search "syntax validation concurrency"

# Retrieve exact implementation body of a symbol
code-kb body Workspace

# Get surgical context bundle: body + callees + types + tests (alias: code-kb slice)
code-kb context ensure_fresh_file

# Find callers or callees of a function (language-agnostically filters stdlib noise)
code-kb refs open_read_only --direction callers

# View callees including external standard library tokens
code-kb refs open_read_only --direction callees --include-external

# Predict blast radius and targeted tests to run for a symbol or file
code-kb blast-radius compute_blast_radius

# Zero-argument blast radius: auto-discovers uncommitted git working-tree changes
code-kb blast-radius
# (alias: code-kb impact)

# Query framework structural facts (or omit category to list all detected categories)
code-kb facts
code-kb facts config --path Cargo.toml
code-kb facts route --limit 10

# Atomically edit a symbol body with pre-flight syntax validation by julie-extract
code-kb edit my_func --file src/lib.rs --body "{\n    println!(\"hello\");\n}"

# View active log file and recent diagnostic messages
code-kb logs

# Token savings, call counts, and error rates (alias: code-kb telemetry)
code-kb stats --since month
code-kb stats --workspace

# Self-contained diagnostic bundle with a pre-filled GitHub issue link
code-kb bug-report --title "lookup returns nothing"

# Output agent lifecycle hook payload (SessionStart / SubagentStart / PreInvocation)
code-kb hook SessionStart
code-kb hook SubagentStart
code-kb hook PreInvocation

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Development

For contributors building code-kb from source:

Prerequisites

• Rust (1.95+ / Edition 2024)
• Extractor binary: Run ./scripts/restore-julie-extract.sh to download the pinned julie-extract binary

Build and Install Locally

# Restore pinned julie-extract binary
./scripts/restore-julie-extract.sh

# Install code-kb binary from local checkout
cargo install --path crates/code-kb-cli --force

Running Tests & Verification

# Run test suite
cargo test --workspace

# Run the plugin launcher and manifest tests
node --test tests/plugin/*.test.cjs

# Run release pre-flight verification
./scripts/release-preflight.sh

To run the Claude Code plugin from this checkout, build and load it. The launcher runs target/release/code-kb when it exists, so no download happens:

cargo build --release
claude --plugin-dir .

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Architecture & Engineering Plans

code-kb was designed based on extensive benchmarking and retrospectives from earlier code intelligence engines:

• 001: Architecture & Service Model — Multi-project workstation scope, Git worktree deduplication, and RAG vs. AST evaluation.
• 002: Workspace Scoping & MCP — 1:1 session binding, eliminating workspace registries and workspace_id friction.
• 003: Tool Catalog & Schema — The core read tools, token-minimized output formats, and replace_symbol_body.
• 004: File Synchronization & Watchers — 3-tier sync: tool-driven updates, JIT staleness guards, and debounced background watching.
• 005: Cold-Start Reconciliation — Detecting and reconciling offline edits in under 50ms on startup.
• 006: Retrospective Lessons from Miller — Analysis of calibration data, performance ledgers, and traps to avoid.
• 010: Master Implementation Plan — The phased engineering roadmap from workspace scaffolding to release.
• ADR 001: Zero Workspace Parameters — Decision record strictly forbidding workspace parameters in tool schemas.
• AGENTS.md Guidelines — Strict architectural invariants and rules for AI coding assistants working in this repository.

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License

Dual-licensed under MIT or Apache-2.0.