Harness Code

• A map before grep

  code_map gives a ranked map of a project’s key files with their signatures, within a token budget, optionally centred on one folder.

• Where it is and who uses it

  code_symbol tells where a function, type or constant is defined, what it uses and who uses it, with path:line and the line of source that makes each link.

• What a change breaks

  code_impact lists everything that depends on a symbol or a file, by caller depth, with tests summarised per file. For before a signature changes.

• How A reaches B

  code_path finds the shortest chain of calls, renders and shared constants between two ends, one hop per line with the call site. An end can even be plain words.

• Always fresh

  Each call compares file sizes and times with the index and reads only what changed. There is no watcher, no commit hook and nothing to rebuild.

• Six languages

  Rust, TypeScript and JavaScript, .svelte, .vue and .astro files, Go and Python. Links across languages are marked as found by name.

• No values in answers

  String literals in signatures are replaced, credential formats and URL passwords are masked, and file names cannot forge a line of an answer.

• Isolated and bounded

  A repository is untrusted input, so it is indexed in a separate worker with a memory and time limit. Only git repositories are indexed, never your home folder.

• Claude Code

  Register with claude mcp add --scope user harness-code -- harness-code mcp.

• Codex

  Register with codex mcp add harness-code -- harness-code mcp.

• OMP, PI, OpenCode

  Add a harness-code entry that runs harness-code mcp: in mcp.json for OMP and PI, under mcp in opencode.json for OpenCode.

• Harness Desktop

  Installs it, registers the server for every harness, keeps it up to date and builds the index of a project when you open it.

• Any other MCP client

  Any MCP client can start the stdio server with harness-code mcp.

1. # macOS and Linux

   $ curl -fsSL https://raw.githubusercontent.com/MSpiechowicz/harness-useful-code/main/install.sh | sh

2. # Windows (PowerShell)

   PS> powershell -ExecutionPolicy Bypass -c "irm https://raw.githubusercontent.com/MSpiechowicz/harness-useful-code/main/install.ps1 | iex"

Prefer a download? Every release and its notes are on the Harness Code releases page.

• Nothing is sent anywhere. The index is one local SQLite file, code.sqlite3, in the harness-code folder of your user data directory.
• Nothing is written into your repositories.
• String values in signatures are hidden, and credential formats and URL passwords are masked in replies.
• Indexing runs in a separate worker with a time limit, and on Linux a memory limit, so a hostile repository cannot take the server down.
• Only git repositories are indexed. Your home folder, hidden folders under it and system folders are refused.

Harness Code is the code graph in Harness Useful, a family of six open-source, local tools for coding-agent harnesses. Harness Desktop is the window, Harness Skills the workflow, Harness Memory the shared project memory, Harness Knowledge the searchable project documentation, Harness Code the code graph and Harness Dashboard the usage and cost meter.

Each tool works on its own. Harness Desktop’s Recommended setup can install the others after you confirm each part and register their MCP servers in each detected harness.

• Harness Desktop Your coding-agent CLI, in a native desktop window.
• Harness Skills From a natural-language request to reviewed, verified work.
• Harness Memory Project memory for your AI coding agents, in one local binary.
• Harness Knowledge Project documentation for your AI coding agents, in one local binary.
• Harness Dashboard Token usage across your AI coding tools, in one local app.

See the Harness Useful home page, every tool side by side or the family FAQ.