{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://research-mcp-mhh.fly.dev/docs/contract/schema.json",
  "title": "research-mcp published contract",
  "description": "Tool I/O, shared envelope, and errors. schema_version constant: 2026-09-14.",
  "definitions": {
    "confidence": {
      "type": "string",
      "enum": ["high", "medium", "low", "unknown"]
    },
    "sourceType": {
      "type": "string",
      "enum": ["primary", "secondary"]
    },
    "researchMode": {
      "type": "string",
      "enum": ["golden", "sample", "live"]
    },
    "failGate": {
      "type": "object",
      "required": ["reason", "retryable"],
      "properties": {
        "reason": {
          "type": "string",
          "description": "Machine-readable gate failure reason (e.g. quote_gate_failed, cogs_cap_exceeded, sample_path)."
        },
        "retryable": {
          "type": "boolean",
          "description": "True when a later retry might succeed (cancel, COGS config)."
        }
      },
      "additionalProperties": false
    },
    "claimExcerpt": {
      "type": "object",
      "required": ["claim", "quote", "source_url"],
      "properties": {
        "claim": { "type": "string" },
        "quote": { "type": "string" },
        "source_url": { "type": "string", "format": "uri" }
      },
      "additionalProperties": false
    },
    "source": {
      "type": "object",
      "required": ["title", "url", "publisher", "accessed", "type", "supports"],
      "properties": {
        "title": { "type": "string" },
        "url": { "type": "string" },
        "publisher": { "type": "string" },
        "accessed": { "type": "string" },
        "type": { "$ref": "#/definitions/sourceType" },
        "supports": { "type": "string" },
        "source": { "type": "string", "enum": ["cached", "live"] },
        "retrieved_at": {
          "type": "string",
          "description": "ISO-8601 when the page body was retrieved, if known."
        }
      },
      "additionalProperties": true
    },
    "researchMeta": {
      "type": "object",
      "required": ["mode", "billable"],
      "properties": {
        "mode": { "$ref": "#/definitions/researchMode" },
        "billable": { "type": "boolean" }
      },
      "additionalProperties": false
    },
    "envelope": {
      "type": "object",
      "required": ["tldr", "body", "confidence", "sources", "gaps", "as_of", "schema_version"],
      "properties": {
        "tldr": { "type": "string" },
        "body": {},
        "confidence": { "$ref": "#/definitions/confidence" },
        "sources": {
          "type": "array",
          "items": { "$ref": "#/definitions/source" }
        },
        "gaps": { "type": "array", "items": { "type": "string" } },
        "as_of": { "type": "string" },
        "schema_version": {
          "type": "string",
          "const": "2026-09-14"
        },
        "meta": { "$ref": "#/definitions/researchMeta" },
        "fail_gate": { "$ref": "#/definitions/failGate" },
        "retrieved_at": { "type": "string" },
        "claims": {
          "type": "array",
          "items": { "$ref": "#/definitions/claimExcerpt" }
        }
      },
      "additionalProperties": true
    },
    "toolError": {
      "type": "object",
      "required": ["error", "message"],
      "properties": {
        "error": {
          "type": "string",
          "enum": [
            "unauthorized",
            "insufficient_credits",
            "preview_required",
            "server_misconfigured",
            "billing_misconfigured"
          ]
        },
        "message": { "type": "string" }
      },
      "additionalProperties": true
    },
    "researchBriefInput": {
      "type": "object",
      "required": ["query", "depth"],
      "properties": {
        "query": { "type": "string" },
        "depth": {
          "type": "string",
          "enum": ["quick", "standard"],
          "description": "Default publish surface. depth=deep requires ENABLE_PREVIEW_TOOLS=1 and is always $0."
        },
        "as_of_hint": { "type": "string" }
      },
      "additionalProperties": false
    },
    "researchBriefOutput": {
      "allOf": [
        { "$ref": "#/definitions/envelope" },
        {
          "type": "object",
          "required": ["query", "depth"],
          "properties": {
            "query": { "type": "string" },
            "depth": { "type": "string", "enum": ["quick", "standard", "deep"] }
          }
        }
      ]
    },
    "sourceLookupInput": {
      "type": "object",
      "required": ["claim_or_url", "ask"],
      "properties": {
        "claim_or_url": { "type": "string" },
        "ask": { "type": "string" }
      },
      "additionalProperties": false
    },
    "sourceLookupOutput": {
      "allOf": [
        { "$ref": "#/definitions/envelope" },
        {
          "type": "object",
          "required": ["claim_or_url", "ask", "verdict", "http_status"],
          "properties": {
            "claim_or_url": { "type": "string" },
            "ask": { "type": "string" },
            "verdict": {
              "type": "string",
              "enum": ["found", "not_found", "moved", "conflicting", "blocked", "unaudited"]
            },
            "http_status": { "type": ["integer", "null"] }
          }
        }
      ]
    },
    "compareOptionsInput": {
      "type": "object",
      "required": ["options", "question", "criteria"],
      "properties": {
        "options": { "type": "array", "items": { "type": "string" }, "minItems": 2 },
        "question": { "type": "string" },
        "criteria": { "type": "array", "items": { "type": "string" }, "minItems": 1 }
      },
      "additionalProperties": false,
      "description": "Preview only when ENABLE_PREVIEW_TOOLS=1; always billable=false."
    },
    "creditsResponse": {
      "type": "object",
      "required": ["schema_version", "packs", "meters_usd", "fail_usd"],
      "properties": {
        "schema_version": { "const": "2026-09-14" },
        "balance_cents": { "type": ["integer", "null"] },
        "balance_usd": { "type": ["number", "null"] },
        "packs": {
          "type": "object",
          "properties": {
            "starter": { "const": 1000 },
            "standard": { "const": 2500 },
            "pro": { "const": 5000 }
          }
        },
        "meters_usd": {
          "type": "object",
          "properties": {
            "lite": { "const": 0.25 },
            "standard": { "const": 0.6 },
            "deep": { "const": 1.5 }
          }
        },
        "fail_usd": { "const": 0 },
        "break_glass": { "type": "boolean" }
      }
    }
  }
}