SuperBizAgent-java/openspec/changes/archive/2026-07-08-executor-composer-final-answer/proposal.md

Why

Stage one removed final-answer fields from Executor, stage two added deterministic Gatekeeper checks, and stage three made Verifier claim-oriented. The remaining gap is final answer rendering: ChatService can still rely on temporary V2 rendering paths instead of a dedicated expression layer, which risks letting unverified Executor material shape user-facing answers.

This phase introduces a Composer expression layer so final Chat answers are generated only from Verifier-allowed material.

What Changes

• Add a chat_composer final-answer generation step after Verifier.
• Add a strict Composer prompt and JSON output contract with answer_summary, recommended_actions, and user_facing_answer.
• Build Composer input in ChatService from filtered Verifier results:
  • allowed_claims
  • allowed_hypotheses
  • missing_info
  • recommended_actions
  • rationale
• Ensure PASS, LOW_CONFID, and REJECT final answers no longer read Executor user_facing_answer or raw Executor JSON.
• Persist Composer output in diagnosis_session.self_evaluation.verifier_evaluation.composer_output.
• Add safe fallback templates for malformed Composer output that never expose raw Executor JSON or raw Composer JSON.

Capabilities

New Capabilities

• chat-composer-agent: Final expression layer that turns Verifier-allowed structured material into a readable Chinese user answer without introducing new facts.

Modified Capabilities

• chat-verifier-agent: ChatService final routing changes so Verifier verdicts feed Composer or safe fixed templates instead of direct Executor answer paths.

Impact

• Affected prompt: add src/main/resources/prompts/chat-composer-prompt.md.
• Affected service: ChatService final rendering after Verifier, Composer input assembly, Composer output parsing, malformed-output fallback.
• Affected audit: diagnosis_session.self_evaluation.verifier_evaluation gains composer_output.
• Affected tests: ChatServiceSequentialAgentTest and focused tests around Composer input filtering, final answer routing, and malformed Composer fallback.
• Database schema: no table or column change.
• External API: no endpoint contract change; final answer text semantics become stricter because unverified Executor material is no longer a source for user-visible answers.

Non-Goals

• No Planner changes.
• No Gatekeeper rule expansion.
• No Verifier classification changes.
• No Executor retry behavior change.
• No database migration.
• No stage-five eval fixture expansion in this phase.