diff --git a/CLAUDE.md b/CLAUDE.md
index 02031c3..3862e39 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -49,6 +49,8 @@ The package is small and self-documenting, so there's no separate `src/` guide.
   `uv run pytest --cov`.
 - **Gates (all required, blocking PR checks):** `ruff check .`,
   `ruff format --check .`, `mypy` (strict), `pytest --cov` at **100% coverage**.
+- Every public module, class, and function needs a docstring, enforced by `ruff` D1;
+  state the contract, don't restate the name.
 
 ## Publishing model checkpoints to HuggingFace (any agent session)
 
diff --git a/README.md b/README.md
index dc91dc7..1f4a3d5 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,7 @@ If you know [Inspect Evals](https://inspect.aisi.org.uk/evals/), this is that fo
 [![CI](https://github.com/robocurve/worldevals/actions/workflows/ci.yml/badge.svg)](https://github.com/robocurve/worldevals/actions/workflows/ci.yml)
 [![License: MIT](https://img.shields.io/badge/license-MIT-green)](LICENSE)
 [![Coverage](https://img.shields.io/badge/coverage-100%25-brightgreen)](https://github.com/robocurve/worldevals/actions/workflows/ci.yml)
+[![Docs coverage](https://img.shields.io/badge/public%20docstrings-100%25-brightgreen)](https://github.com/robocurve/worldevals/actions/workflows/ci.yml)
 [![Built on Inspect Robots](https://img.shields.io/badge/built%20on-Inspect%20Robots-indigo)](https://github.com/robocurve/inspect-robots)
 
 **[Browse the catalog → worldevals.org](https://worldevals.org/)**
@@ -104,6 +105,9 @@ Published checkpoints are catalogued in [WorldPolicies](https://github.com/roboc
 > forget. Day-to-day conventions (PR-only `main`, the required `ci-ok` check,
 > one-click releases) are documented in [`CLAUDE.md`](CLAUDE.md).
 
+Every public module, class, and function needs a docstring, enforced by `ruff` D1;
+state the contract, don't restate the name.
+
 ```bash
 uv venv && uv pip install -e ".[dev]"     # inspect_robots resolved from the v0.3.0 tag
 uv run pre-commit install
diff --git a/docs/contributing.md b/docs/contributing.md
index c2252f9..9caf7c8 100644
--- a/docs/contributing.md
+++ b/docs/contributing.md
@@ -39,4 +39,7 @@ name, well-formed `https://github.com/...` repo URL, ≥1 task key), and CI requ
 100% coverage. Keep `task_keys` in sync with the benchmark's actual registered
 task names.
 
+Every public module, class, and function needs a docstring, enforced by `ruff` D1;
+state the contract, don't restate the name.
+
 See the [API reference](api.md) for the `Benchmark` fields.
diff --git a/pyproject.toml b/pyproject.toml
index 87d0f4c..e6b913a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -72,7 +72,12 @@ target-version = "py310"
 src = ["src", "tests"]
 
 [tool.ruff.lint]
-select = ["E", "F", "W", "I", "UP", "B", "C4", "SIM", "RUF"]
+select = ["E", "F", "W", "I", "UP", "B", "C4", "SIM", "RUF", "D1"]
+ignore = ["D105", "D107"]
+
+[tool.ruff.lint.per-file-ignores]
+"scripts/**" = ["D1"]
+"tests/**" = ["D1"]
 
 [tool.ruff.lint.isort]
 known-first-party = ["worldevals"]
diff --git a/src/worldevals/cli.py b/src/worldevals/cli.py
index d4bbf28..a8494bd 100644
--- a/src/worldevals/cli.py
+++ b/src/worldevals/cli.py
@@ -9,6 +9,7 @@
 
 
 def build_parser() -> argparse.ArgumentParser:
+    """Create the argument parser for the catalog browsing commands."""
     parser = argparse.ArgumentParser(
         prog="worldevals",
         description="WorldEvals — the Inspect Evals for robotics (a benchmark catalog).",
@@ -67,6 +68,7 @@ def _cmd_tasks() -> int:
 
 
 def main(argv: Sequence[str] | None = None) -> int:
+    """Run the catalog CLI and return its process exit status."""
     parser = build_parser()
     args = parser.parse_args(argv)
     if args.command == "list":