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description: "Use when setting up a project environment — installing dependencies, verifying builds, detecting the tech stack. Covers Phase 0 of a new session."

Environment Setup

Stack Detection

Read these files to understand what needs to be installed:

File	Indicates
package.json	Node project — run npm ci
pyproject.toml	Python project — run pip install -e . or uv pip install -e .
requirements.txt	Python deps — run pip install -r requirements.txt
Cargo.toml	Rust project — run cargo build
go.mod	Go project — run go mod download

Check CLAUDE.md and README.md first — they may specify exact setup commands.

Install Order

1. Read project config files
2. Install backend dependencies
3. Install frontend dependencies (if separate)
4. Run the build to verify it works
5. Run tests to verify the environment is healthy

If Build Fails

• Read the error carefully — most setup failures are missing system deps or wrong versions
• Check if there's a .tool-versions, .nvmrc, or Dockerfile that specifies required versions
• If a dep is missing from the lockfile, do NOT add it yourself — flag it

Pre-installed Tools

See the verification-rules appended to build/review agent prompts for the full list. Key ones already in the sandbox: pytest, pyright, ruff, tsc, eslint. Do NOT pip/npm install these.