@vitest-agent/sidecar

Part of the vitest-agent ecosystem. Most users want @vitest-agent/plugin, which pulls this package in automatically (it installs automatically with the CLI; you rarely add it directly).

A Node Single Executable Application (SEA) binary for the per-Bash-call inject-env hot path. Every Bash tool call from a Claude Code agent fires the plugin's pre-tool-use/bash.sh hook, which detects Vitest invocations and prepends the canonical VITEST_AGENT_* env prefix. Running that through the full vitest-agent CLI pays Node cold-start latency on every call; this binary runs the same logic with a fraction of the startup cost.

Features

• Native binary — Node SEA wrapping the same inject-env TypeScript that ships in @vitest-agent/cli; JS fallback and binary stay byte-identical
• Per-platform sub-packages — @vitest-agent/sidecar-darwin-arm64, @vitest-agent/sidecar-linux-arm64, @vitest-agent/sidecar-linux-x64, @vitest-agent/sidecar-win32-x64 as optionalDependencies; only the matching one installs
• resolveSidecarBinaryPath() — exported function that returns the absolute path of the installed binary, or null on unsupported platforms

Install

npm install --save-dev @vitest-agent/plugin
# @vitest-agent/sidecar arrives transitively through @vitest-agent/cli

The plugin's SessionStart hook resolves the binary path once per session via vitest-agent agent sidecar-path and exports VITEST_AGENT_SIDECAR_BIN. The PreToolUse Bash hook reads that env var and execs the binary directly — no PATH lookup, no Node startup. On unsupported platforms the hook falls back to the vitest-agent JS CLI automatically.

Documentation

Package reference at vitest-agent.dev/sidecar.

License

MIT