microsoft/tgrep

Trigram-indexed grep with a client/server architecture for fast regex search in large codebases.

tgrep is integrated into GitHub Copilot CLI to power fast grep searches across large repositories.

Install tgrep, then start a server:

Without a server, run tgrep index . to build an on-disk index. Searches use the server when available, then the local index, or scan the filesystem if no usable index exists. Indexes are stored in .tgrep/ by default; add this directory to .gitignore. It is generated build output and must not be committed or distributed with a repository. Build indexes locally for repositories you search; index metadata is not a statement of trust or freshness.

Indexed file reads stay beneath the selected root and do not follow descendant symlinks or Windows reparse points. Invalid stored paths are rejected; indexes with an unavailable or unrelated recorded root fall back to a filesystem scan. Explicit file arguments and --no-index --follow retain their normal scan semantics.

Indexes can lag filesystem changes. The server updates asynchronously; without a server, rerun tgrep index . after changes. Use --no-index when a search must read the current files. Queries scan during an initial build until complete coverage is available.

For coding agents, see AGENTS.md. To install MCP search tools and startup hooks for Codex or pi, run bash install-agent.sh from this checkout (Linux/macOS, Python 3.11+). See the agent integration guide.