{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://kb.local/wire/v1/answer.schema.json",
  "title": "Answer v1",
  "description": "Stub schema — declares the schema_version label and the required fields per design §2.3.",
  "type": "object",
  "required": [
    "schema_version",
    "answer",
    "citations",
    "grounded",
    "model",
    "prompt_template_version",
    "retrieval",
    "usage",
    "created_at"
  ],
  "properties": {
    "schema_version":          { "const": "answer.v1" },
    "answer":                  { "type": "string" },
    "citations":               { "type": "array" },
    "grounded":                { "type": "boolean" },
    "refusal_reason":          {
      "anyOf": [
        {
          "type": "string",
          "enum": [
            "score_gate",
            "llm_self_judge",
            "no_index",
            "no_chunks",
            "llm_stream_aborted",
            "multi_hop_decompose_failed",
            "nli_verification_failed",
            "nli_model_unavailable"
          ]
        },
        { "type": "null" }
      ],
      "description": "p9-fb-41: `multi_hop_decompose_failed` added in PR-2 alongside the multi-hop pipeline skeleton (only emitted when AskOpts.multi_hop = true and the decompose LLM call fails to parse). `nli_verification_failed` + `nli_model_unavailable` added in PR-9c-1 — both emitted only on the multi-hop path when `[rag].nli_threshold > 0`; surface declared in PR-9c-1, behavior wired in PR-9c-2."
    },
    "model":                   { "type": "object" },
    "embedding":               { "type": ["object", "null"] },
    "prompt_template_version": { "type": "string" },
    "retrieval":               { "type": "object" },
    "usage":                   { "type": "object" },
    "created_at":              { "type": "string", "format": "date-time" },
    "conversation_id":         {
      "type": ["string", "null"],
      "description": "p9-fb-15: same conversation 의 turn 들이 공유. CLI single-shot / TUI 첫 turn 은 null."
    },
    "turn_index":              {
      "type": ["integer", "null"],
      "minimum": 0,
      "description": "p9-fb-15: 같은 conversation 안 0-based 순서. null 이면 single-shot."
    },
    "hops": {
      "anyOf": [
        {
          "type": "array",
          "items": { "$ref": "#/$defs/HopRecord" }
        },
        { "type": "null" }
      ],
      "description": "p9-fb-41 multi-hop trace. Present (non-null array) only when the ask routed through the multi-hop pipeline (`AskOpts.multi_hop = true`); single-pass answers omit the field entirely (serde `skip_serializing_if = None`). Each entry records one LLM hop — decompose / decide / synthesize — with sub-queries, retrieval count, and per-hop latency. Wire-additive: pre-fb-41 readers tolerate the missing field; new readers branch on its presence to render the per-hop trace."
    },
    "verification": {
      "anyOf": [
        { "$ref": "#/$defs/VerificationSummary" },
        { "type": "null" }
      ],
      "description": "p9-fb-41 PR-9c-1: NLI-based groundedness verification summary. Present only when `[rag].nli_threshold > 0` and multi-hop ask reached step 8.5 (single-pass ask never verifies). Surface declared in PR-9c-1; the actual stamp lands in PR-9c-2. Wire-additive: pre-v0.18 readers tolerate the missing field."
    }
  },
  "$defs": {
    "HopRecord": {
      "type": "object",
      "required": ["iter", "kind", "context_chunks_added", "forced_stop", "llm_call_ms"],
      "properties": {
        "iter": {
          "type": "integer",
          "minimum": 0,
          "description": "0-based hop index. iter=0 is always the initial decompose; subsequent iters are decide calls; the final iter is the synthesize call."
        },
        "kind": {
          "type": "string",
          "enum": ["decompose", "decide", "synthesize"]
        },
        "sub_queries": {
          "type": "array",
          "items": { "type": "string" },
          "description": "Per-kind semantics. Decompose: the initial sub-queries the LLM produced. Decide: the *new* sub-queries to retrieve next iter (empty when the LLM signalled stop or when forced_stop=true). Synthesize: always empty."
        },
        "context_chunks_added": {
          "type": "integer",
          "minimum": 0,
          "description": "Number of *new* chunks the retrieval round contributed to the pool (deduped by chunk_id). 0 for decompose / synthesize hops."
        },
        "forced_stop": {
          "type": "boolean",
          "description": "True when the pipeline cut the loop short due to a safety cap (max_depth / max_pool_chunks) rather than the LLM's own stop signal. Tracing signal, not a refusal."
        },
        "llm_call_ms": {
          "type": "integer",
          "minimum": 0,
          "description": "Wall-clock latency of the LLM call for this hop. `0` is overloaded — means 'no LLM call happened' when (a) the Decide hop was skipped due to forced_stop or (b) the pool was empty before any decide could run. Treat 0 as absent or instantaneous."
        }
      }
    },
    "VerificationSummary": {
      "type": "object",
      "required": ["nli_score", "nli_threshold", "nli_passed"],
      "properties": {
        "nli_score": {
          "type": "number",
          "description": "p9-fb-41 PR-9c-1: NLI entailment channel score (faithfulness) — `NliScores::faithfulness()` of `(premise = packed chunks, hypothesis = answer)`."
        },
        "nli_threshold": {
          "type": "number",
          "description": "p9-fb-41 PR-9c-1: mirror of `[rag].nli_threshold` at the time the verification ran (audit field — same value the pipeline gates on)."
        },
        "nli_passed": {
          "type": "boolean",
          "description": "p9-fb-41 PR-9c-1: `nli_score >= nli_threshold`. When false, the matching wire emit also carries `refusal_reason = \"nli_verification_failed\"`."
        }
      }
    }
  }
}