This milestone adds a deterministic Anthropic-compatible mock service plus a reproducible CLI harness for the Rust claw binary.
crates/mock-anthropic-service/ — mock /v1/messages servicecrates/rusty-claude-cli/tests/mock_parity_harness.rs — end-to-end clean-environment harnessscripts/run_mock_parity_harness.sh — convenience wrapperThe harness runs these scripted scenarios against a fresh workspace and isolated environment variables:
streaming_textread_file_roundtripgrep_chunk_assemblywrite_file_allowedwrite_file_deniedcd rust/
./scripts/run_mock_parity_harness.sh
cd rust/
cargo run -p mock-anthropic-service -- --bind 127.0.0.1:0
The server prints MOCK_ANTHROPIC_BASE_URL=...; point ANTHROPIC_BASE_URL at that URL and use any non-empty ANTHROPIC_API_KEY.