{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "durable-workflow.v2.mcp-tool-results",
  "title": "Durable Workflow MCP tool-result envelopes",
  "description": "Normative JSON Schema for MCP tool-result envelopes returned by Durable Workflow tools. Result status, payload preview truncation, error envelope fields, and schema/version markers are contractual. Human-readable text and model hints are diagnostic.",
  "type": "object",
  "x-durable-workflow-catalog-entry": "mcp_tool_results",
  "x-durable-workflow-catalog-schema": "durable-workflow.v2.platform-protocol-specs.catalog",
  "x-durable-workflow-catalog-version": 13,
  "x-durable-workflow-owner-symbol": "docs/mcp-workflows.md Tool Result Contract and static/platform-protocol-specs/mcp-tool-results.schema.json",
  "x-durable-workflow-evolution-rule": "additive_minor_breaking_major",
  "x-durable-workflow-object-families": [
    {
      "name": "mcp_tool_result_envelope",
      "owner_repo": "durable-workflow/durable-workflow.github.io",
      "schema_authority": "docs/mcp-workflows.md Tool Result Contract and static/platform-protocol-specs/mcp-tool-results.schema.json",
      "version_authority": "durable-workflow.v2.mcp-tool-results"
    }
  ],
  "required": ["schema", "version", "status"],
  "additionalProperties": true,
  "properties": {
    "schema": {
      "type": "string",
      "const": "durable-workflow.v2.mcp-tool-result"
    },
    "version": {
      "type": "integer",
      "minimum": 1
    },
    "status": {
      "type": "string",
      "enum": ["ok", "error"]
    },
    "result": {
      "type": ["object", "array", "string", "number", "boolean", "null"]
    },
    "payload_preview": {
      "type": ["string", "null"],
      "description": "Human-readable payload preview. The complete machine payload must live in result or be explicitly unavailable."
    },
    "payload_preview_truncated": {
      "type": "boolean"
    },
    "payload_preview_limit_bytes": {
      "type": "integer",
      "minimum": 0
    },
    "error": {
      "$ref": "#/$defs/error"
    },
    "meta": {
      "type": "object",
      "additionalProperties": true
    },
    "content": {
      "type": "array",
      "description": "MCP content blocks. Tools may include these for client compatibility, but the result object remains the machine contract.",
      "items": {
        "type": "object",
        "additionalProperties": true,
        "required": ["type"],
        "properties": {
          "type": { "type": "string" },
          "text": { "type": ["string", "null"] },
          "mimeType": { "type": ["string", "null"] }
        }
      }
    }
  },
  "allOf": [
    {
      "if": {
        "properties": { "status": { "const": "error" } },
        "required": ["status"]
      },
      "then": {
        "required": ["error"]
      }
    }
  ],
  "$defs": {
    "error": {
      "type": ["object", "null"],
      "additionalProperties": true,
      "properties": {
        "code": { "type": ["string", "null"] },
        "message": { "type": ["string", "null"] },
        "reason": { "type": ["string", "null"] },
        "remediation": { "type": ["string", "null"] },
        "retryable": { "type": ["boolean", "null"] },
        "details": { "type": ["object", "null"], "additionalProperties": true }
      }
    }
  }
}