diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..49c53ab
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,14 @@
+# CLAUDE.md — ChainWeaver
+
+This file is the entry point for Claude Code. All project context, architecture details,
+coding conventions, and guardrails are maintained in a single canonical source:
+
+→ **Read [AGENTS.md](AGENTS.md) before making any changes.**
+
+## Quick invariants (also in AGENTS.md § Core invariants)
+
+1. No LLM calls in `executor.py` — deterministic by design.
+2. All exceptions inherit from `ChainWeaverError`.
+3. All public symbols exported in `chainweaver/__init__.py` `__all__`.
+4. `from __future__ import annotations` at the top of every module.
+5. All new code must pass: `ruff check`, `ruff format --check`, `mypy`, `pytest`.