{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://smartergpt.dev/schemas/execution-receipt.v1.schema.json",
  "title": "ExecutionReceipt",
  "description": "D3 output: immutable record of what happened (not what was intended)",
  "type": "object",
  "required": ["schemaVersion", "phase", "timestamp", "inputDigest", "receipt", "outputDigest"],
  "properties": {
    "schemaVersion": {
      "type": "string",
      "const": "1.0.0"
    },
    "phase": {
      "type": "string",
      "const": "D3"
    },
    "timestamp": {
      "type": "string",
      "format": "date-time",
      "description": "ISO 8601 UTC timestamp"
    },
    "inputDigest": {
      "type": "string",
      "pattern": "^sha256:[a-f0-9]{64}$",
      "description": "Must match MergePlan.outputDigest"
    },
    "receipt": {
      "$ref": "#/$defs/Receipt"
    },
    "outputDigest": {
      "type": "string",
      "pattern": "^sha256:[a-f0-9]{64}$",
      "description": "SHA256 digest of receipt content"
    }
  },
  "$defs": {
    "Receipt": {
      "type": "object",
      "required": ["outcome", "stepResults", "links", "budget"],
      "properties": {
        "outcome": {
          "type": "string",
          "enum": ["success", "partial", "failed", "aborted"],
          "description": "Overall execution result"
        },
        "stepResults": {
          "type": "array",
          "items": { "$ref": "#/$defs/StepResult" }
        },
        "links": {
          "$ref": "#/$defs/Links",
          "description": "Verifiable artifacts produced"
        },
        "budget": {
          "$ref": "#/$defs/BudgetUsage"
        },
        "failures": {
          "type": "array",
          "items": { "$ref": "#/$defs/Failure" },
          "description": "Classified failures with evidence"
        }
      }
    },
    "StepResult": {
      "type": "object",
      "required": ["stepId", "status", "startedAt", "completedAt"],
      "properties": {
        "stepId": {
          "type": "integer",
          "description": "Matches step from MergePlan"
        },
        "status": {
          "type": "string",
          "enum": ["success", "failed", "skipped", "blocked", "aborted"]
        },
        "startedAt": {
          "type": "string",
          "format": "date-time"
        },
        "completedAt": {
          "type": "string",
          "format": "date-time"
        },
        "durationMs": {
          "type": "integer",
          "minimum": 0
        },
        "attempt": {
          "type": "integer",
          "minimum": 1,
          "default": 1
        },
        "evidence": {
          "$ref": "#/$defs/Evidence"
        },
        "error": {
          "$ref": "#/$defs/Error"
        }
      }
    },
    "Evidence": {
      "type": "object",
      "description": "Proof that action was taken",
      "properties": {
        "mergeSha": {
          "type": "string",
          "pattern": "^[a-f0-9]{40}$",
          "description": "Resulting commit SHA from merge"
        },
        "prUrl": {
          "type": "string",
          "format": "uri",
          "description": "Link to PR"
        },
        "commitUrl": {
          "type": "string",
          "format": "uri",
          "description": "Link to commit"
        },
        "ciRunUrl": {
          "type": "string",
          "format": "uri",
          "description": "Link to CI run"
        },
        "reviewUrl": {
          "type": "string",
          "format": "uri"
        },
        "umbranchSha": {
          "type": "string",
          "pattern": "^[a-f0-9]{40}$",
          "description": "SHA of umbrella branch after step"
        }
      }
    },
    "Error": {
      "type": "object",
      "required": ["code", "message"],
      "properties": {
        "code": {
          "type": "string",
          "description": "Machine-readable error code"
        },
        "message": {
          "type": "string",
          "description": "Human-readable message"
        },
        "details": {
          "type": "object",
          "description": "Additional context"
        }
      }
    },
    "Links": {
      "type": "object",
      "description": "Verifiable links to artifacts",
      "properties": {
        "finalSha": {
          "type": "string",
          "pattern": "^[a-f0-9]{40}$",
          "description": "Final state of target branch"
        },
        "pullRequests": {
          "type": "array",
          "items": {
            "type": "object",
            "required": ["number", "url", "status"],
            "properties": {
              "number": { "type": "integer" },
              "url": { "type": "string", "format": "uri" },
              "status": { "type": "string", "enum": ["merged", "open", "closed"] }
            }
          }
        },
        "commits": {
          "type": "array",
          "items": {
            "type": "object",
            "required": ["sha", "url"],
            "properties": {
              "sha": { "type": "string", "pattern": "^[a-f0-9]{40}$" },
              "url": { "type": "string", "format": "uri" }
            }
          }
        },
        "ciRuns": {
          "type": "array",
          "items": {
            "type": "string",
            "format": "uri"
          }
        }
      }
    },
    "BudgetUsage": {
      "type": "object",
      "required": ["stepsExecuted", "mergesPerformed", "retriesUsed", "durationMs"],
      "properties": {
        "stepsExecuted": {
          "type": "integer",
          "minimum": 0
        },
        "mergesPerformed": {
          "type": "integer",
          "minimum": 0
        },
        "retriesUsed": {
          "type": "integer",
          "minimum": 0
        },
        "durationMs": {
          "type": "integer",
          "minimum": 0
        }
      }
    },
    "Failure": {
      "type": "object",
      "required": ["class", "stepId", "description"],
      "properties": {
        "class": {
          "type": "string",
          "enum": [
            "transient",
            "deterministic",
            "external",
            "budget_exceeded",
            "policy_violation"
          ],
          "description": "Failure classification for retry decisions"
        },
        "stepId": {
          "type": "integer"
        },
        "description": {
          "type": "string"
        },
        "retryable": {
          "type": "boolean"
        },
        "rootCause": {
          "type": "string",
          "description": "Best-effort root cause analysis"
        }
      }
    }
  }
}