Hooks

Where it lives

• hooks/session-start.shRunsGitHub ↗
  Read the script

  #!/usr/bin/env bash
  # Harness Evolver — SessionStart hook
  # Ensures Python venv, langsmith, langsmith-cli, and env vars are ready.
  # Runs silently on every session start. Installs deps only if missing.
  
  set -euo pipefail
  
  # Resolve paths — plugin root is set by Claude Code
  PLUGIN_ROOT="${CLAUDE_PLUGIN_ROOT:-}"
  PLUGIN_DATA="${CLAUDE_PLUGIN_DATA:-}"
  
  # Fallback: if running outside plugin system (npx install), use legacy paths
  if [ -z "$PLUGIN_ROOT" ]; then
      PLUGIN_ROOT="$HOME/.evolver"
      PLUGIN_DATA="$HOME/.evolver"
  fi
  
  TOOLS_DIR="$PLUGIN_ROOT/tools"
  VENV_DIR="$PLUGIN_DATA/venv"
  VENV_PY="$VENV_DIR/bin/python"
  
  # --- 1. Create venv if missing ---
  if [ ! -f "$VENV_PY" ]; then
      if command -v uv >/dev/null 2>&1; then
          uv venv "$VENV_DIR" >/dev/null 2>&1
      else
          python3 -m venv "$VENV_DIR" >/dev/null 2>&1
      fi
  fi
  
  # --- 2. Install langsmith if missing ---
  if [ -f "$VENV_PY" ]; then
      "$VENV_PY" -c "import langsmith" 2>/dev/null || {
          if command -v uv >/dev/null 2>&1; then
              uv pip install --python "$VENV_PY" langsmith >/dev/null 2>&1
          else
              "$VENV_DIR/bin/pip" install --upgrade langsmith >/dev/null 2>&1 || \
              "$VENV_PY" -m pip install --upgrade langsmith >/dev/null 2>&1
          fi
      }
  fi
  
  # --- 3. Install langsmith-cli if missing ---
  command -v langsmith-cli >/dev/null 2>&1 || {
      if command -v uv >/dev/null 2>&1; then
          uv tool install langsmith-cli >/dev/null 2>&1
      else
          pip install langsmith-cli >/dev/null 2>&1 || pip3 install langsmith-cli >/dev/null 2>&1
      fi
  } || true
  
  # --- 4. Load API key from credentials file if not in env ---
  if [ -z "${LANGSMITH_API_KEY:-}" ]; then
      if [ "$(uname)" = "Darwin" ]; then
          CREDS="$HOME/Library/Application Support/langsmith-cli/credentials"
      else
          CREDS="$HOME/.config/langsmith-cli/credentials"
      fi
      if [ -f "$CREDS" ]; then
          KEY=$(grep '^LANGSMITH_API_KEY=' "$CREDS" 2>/dev/null | head -1 | cut -d= -f2-)
          if [ -n "$KEY" ]; then
              echo "export LANGSMITH_API_KEY=\"$KEY\"" >> "$CLAUDE_ENV_FILE"
          fi
      fi
  fi
  
  # --- 5. Export env vars for skills ---
  if [ -n "${CLAUDE_ENV_FILE:-}" ]; then
      echo "export EVOLVER_TOOLS=\"$TOOLS_DIR\"" >> "$CLAUDE_ENV_FILE"
      echo "export EVOLVER_PY=\"$VENV_PY\"" >> "$CLAUDE_ENV_FILE"
  fi
  

Read the script before you install anything that runs on your machine. This is the one part of a plugin that acts without being asked.