For agents, on top of README.md, which they read first.

• Third-party SDKs are named once, in [workspace.dependencies]. A crate here exists so that consumers stop pinning the third party themselves; do not re-export the third party's types from a crate's public API, or the pin leaks back out.
• A new crate gets its own README.md and CLAUDE.md when the directory is created, and a row in the table above.
• The toolchain is mise.toml's; run mise run test, never cargo directly, and nothing here may require nix. (On a machine with no C compiler on PATH, wrap it: nix shell nixpkgs#stdenv.cc -c mise run test.)
• A crate that a cloned project consumes is used through that project's submodule of this repository, so a crate's public API is a pin its consumers move on purpose: keep the README's surface true.