docs(rfc): clarify read-existing adapter contract

AGENTS.md

@@ -52,6 +52,7 @@ Memory records should capture reusable lessons, not logs: benchmark surprises, C
 - Every registered MCP tool must have a CLI access path.
 - Main CLI flags and standalone scripts are guarded by `tests/contracts/test_mcp_cli_parity_contract.py`.
 - MCP-equivalent CLI handler arguments, required file-path checks, and TOON output are guarded by `tests/unit/cli/test_mcp_commands.py`.
+- RFC-0022 Phase 0 has one narrow process-local exception: the `edit.release_snapshot` action, snapshot/generation/lease controls, and a `read_existing` sequence that requires those controls are exercised through the non-public same-process CLI-handler bridge rather than exposed as unusable cross-invocation CLI operations. Every other action-level CLI path and parameter remains mandatory; parity contracts must encode this exact exception, which does not authorize another tool, a one-shot composition command, or any other waiver.
 - When adding or changing an MCP tool, update the CLI path in the same change and run a real CLI smoke test, for example `uv run python -m tree_sitter_analyzer <file> --smart-context --format json`.
 - This keeps MCP-only features from becoming invisible to users, CI, and future agents.