Sections

Docs · Start

What Sentinel is

Sentinel is a coding agent that lives in your terminal. It streams answers from your choice of LLM, reads and edits files through a sandboxed local tool set, manages chat sessions as plain JSON on disk, and optionally exposes itself to other AI tools over MCP.

What's inside

  • bin/sentinel.js: entry point (TUI / ask / mcp / --version)
  • src/agent/: loop, providers, tools glue, cost, sessions, prompt
  • src/shared/tools/: read, write, edit, glob, grep, bash…
  • src/shared/models/: registry + live discovery from provider APIs
  • src/tui/: the Ink (React) terminal UI
  • mcp/: MCP stdio server (health, ask, review-diff)

The agent loop

src/agent/loop.js is the whole brain: user input → stream from provider → execute tool calls in-process (sandboxed to the project directory) → feed results back → repeat until done or MAX_ITERATIONS. It yields typed events (text, tool_call, tool_result, finish, error) that both the TUI and CLI consume.

repo layout
bin/sentinel.js      entry point
src/cli/main.js      ask, version, help
src/agent/           loop, providers, sessions
src/shared/tools/    sandboxed local tools
src/tui/             Ink terminal UI
mcp/                 stdio server