The analog RAG/bootstrap formatter already rejected missing and literal unknown phases, but still accepted arbitrary phase strings. Keep the parser aligned with the runtime/service contract by allowlisting the known emitted phases and returning the existing typed error shape with received value and field context when drift appears.
Constraint: Scope is limited to claw-analog bootstrap/RAG phase parsing for ROADMAP #693.
Rejected: Preserve arbitrary non-empty phases | would continue hiding producer/parser phase drift.
Confidence: high
Scope-risk: narrow
Directive: Update KNOWN_RAG_BOOTSTRAP_PHASES when claw-rag-service deliberately adds a new response phase.
Tested: cargo fmt --manifest-path rust/Cargo.toml --all -- --check; cargo test --manifest-path rust/Cargo.toml -p claw-analog rag_response -- --nocapture; cargo test --manifest-path rust/Cargo.toml -p claw-analog -- --nocapture; cargo check --manifest-path rust/Cargo.toml -p claw-analog; cargo check --manifest-path rust/Cargo.toml --workspace; git diff --check
Not-tested: Full workspace cargo test; remote CI
