ci: add Python lint/format gate to pre-commit hook (#4528)

.husky/lint-python.sh

@@ -0,0 +1,33 @@
+#!/usr/bin/env sh
+# Lint staged Python files against each project's own ruff config. strands-py/ and
+# harness-py/ each carry their own [tool.ruff]; ruff resolves the nearest config per file,
+# so one invocation covers both. Runs ruff only (no mypy) as a fast pre-filter; CI's lint
+# job remains the source of truth. Range matches the root pyproject.toml and both SDKs so the
+# hook and CI resolve the same ruff.
+set -eu
+
+RUFF_SPEC='ruff>=0.16.0,<0.17.0'
+
+staged_python_files=$(
+  git diff --cached --name-only --diff-filter=ACMR -- strands-py harness-py \
+    | { grep -E '\.py$' || true; }
+)
+
+if [ -z "$staged_python_files" ]; then
+  echo "No staged Python files under strands-py/ or harness-py/; skipping ruff."
+  exit 0
+fi
+
+if ! command -v uvx >/dev/null 2>&1; then
+  echo "uvx not found. Install uv (https://docs.astral.sh/uv/) to run the Python lint hook." >&2
+  exit 1
+fi
+
+echo "Linting staged Python files with ruff..."
+status=0
+printf '%s\n' "$staged_python_files" | xargs uvx --from "$RUFF_SPEC" ruff check || status=1
+printf '%s\n' "$staged_python_files" | xargs uvx --from "$RUFF_SPEC" ruff format --check || status=1
+if [ "$status" -ne 0 ]; then
+  echo "Python lint/format failed. Fix with 'ruff check --fix' and 'ruff format'. Commit aborted." >&2
+  exit 1
+fi

.husky/pre-commit

@@ -1,5 +1,9 @@
 echo "Running pre-commit checks..."
 
+# Lint staged Python files (strands-py/, harness-py/) with ruff — a fast pre-filter, not full CI parity
+echo "Linting Python..."
+npm run lint:py || { echo "Python lint failed. Commit aborted."; exit 1; }
+
 # Build (required for integ type-check: workspace symlink resolves to dist/)
 echo "Building..."
 npm run build || { echo "Build failed. Commit aborted."; exit 1; }

harness-py/pyproject.toml

@@ -44,7 +44,7 @@ litellm = ["strands-agents[litellm]"]
 dev = [
     "pytest>=8.0.0,<9.0.0",
     "pytest-asyncio>=0.24.0,<1.0.0",
-    "ruff>=0.9.0,<1.0.0",
+    "ruff>=0.16.0,<0.17.0",
     "strands-agents[openai,anthropic,gemini,ollama,litellm]",
     "openai>=2.0.0,<3.0.0",
     # The MCP test fixtures use mcp v1's FastMCP API; the SDK allows mcp 2.x, which renamed it.

package.json

@@ -26,6 +26,7 @@
     "test:browser:install": "npm run test:browser:install -w strands-ts",
     "test:package": "npm run test:package -w strands-ts",
     "lint": "npm run lint -w strands-ts",
+    "lint:py": "sh .husky/lint-python.sh",
     "format": "npm run format -w strands-ts",
     "format:check": "npm run format:check -w strands-ts",
     "type-check": "npm run type-check -w strands-ts",

pyproject.toml

@@ -4,8 +4,9 @@ version = "0.0.0"
 description = "Shared Python tooling for the Strands monorepo. Not published."
 requires-python = ">=3.10"
 dependencies = [
-    # Linter/formatter.
+    # Linter/formatter. Range matches strands-py and harness-py so the whole monorepo
-    "ruff>=0.13.0,<0.15.0",
+    # (and the pre-commit hook) resolves the same ruff.
+    "ruff>=0.16.0,<0.17.0",
     # Type checker.
     "pyright>=1.1.400",
     # Test runner for the shared venv.

strands-py/pyproject.toml

@@ -109,7 +109,7 @@ dev = [
     "pytest-asyncio>=1.0.0,<1.5.0",
     "pytest-timeout>=2.0.0,<3.0.0",
     "pytest-xdist>=3.0.0,<4.0.0",
-    "ruff>=0.13.0,<0.17.0",
+    "ruff>=0.16.0,<0.17.0",
     "tenacity>=9.0.0,<10.0.0",
 ]
 
@@ -135,7 +135,7 @@ installer = "uv"
 features = ["all"]
 dependencies = [
   "mypy>=1.15.0,<3.0.0",
-  "ruff>=0.13.0,<0.17.0",
+  "ruff>=0.16.0,<0.17.0",
   # Include required package dependencies for mypy
   "boto3-stubs[bedrock-agent,bedrock-agent-runtime,s3]>=1.26.0,<2.0.0",
   "strands-agents @ {root:uri}",