{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://smartergpt.dev/schemas/merge-plan.v1.schema.json",
  "title": "MergePlan",
  "description": "D2 output: ordered action plan with EID citations (human-reviewable)",
  "type": "object",
  "required": ["schemaVersion", "phase", "timestamp", "inputDigest", "plan", "outputDigest"],
  "properties": {
    "schemaVersion": {
      "type": "string",
      "const": "1.0.0"
    },
    "phase": {
      "type": "string",
      "const": "D2"
    },
    "timestamp": {
      "type": "string",
      "format": "date-time",
      "description": "ISO 8601 UTC timestamp"
    },
    "inputDigest": {
      "type": "string",
      "pattern": "^sha256:[a-f0-9]{64}$",
      "description": "Must match AnalysisPool.outputDigest"
    },
    "plan": {
      "$ref": "#/$defs/Plan"
    },
    "outputDigest": {
      "type": "string",
      "pattern": "^sha256:[a-f0-9]{64}$",
      "description": "SHA256 digest of plan content"
    }
  },
  "$defs": {
    "Plan": {
      "type": "object",
      "required": ["strategy", "steps", "budget"],
      "properties": {
        "strategy": {
          "type": "string",
          "enum": ["serial", "pyramid", "umbrella"],
          "description": "Merge strategy to use"
        },
        "steps": {
          "type": "array",
          "items": { "$ref": "#/$defs/Step" },
          "description": "Ordered list of actions"
        },
        "budget": {
          "$ref": "#/$defs/Budget"
        },
        "secondStar": {
          "type": "string",
          "pattern": "^[a-f0-9]{40}$",
          "description": "Target SHA - the point of truth we're merging toward"
        },
        "umbranchName": {
          "type": "string",
          "description": "Umbrella branch name (if strategy is umbrella)"
        }
      }
    },
    "Step": {
      "type": "object",
      "required": ["stepId", "action", "entity", "citations"],
      "properties": {
        "stepId": {
          "type": "integer",
          "minimum": 1,
          "description": "Sequential step number"
        },
        "action": {
          "type": "string",
          "enum": [
            "merge",
            "rebase",
            "wait_ci",
            "request_review",
            "resolve_conflict",
            "skip",
            "create_umbrella",
            "finalize_umbrella"
          ]
        },
        "entity": {
          "type": "string",
          "description": "EID of the entity this step operates on"
        },
        "dependsOn": {
          "type": "array",
          "items": { "type": "integer" },
          "description": "Step IDs that must complete first"
        },
        "citations": {
          "type": "array",
          "items": { "$ref": "#/$defs/Citation" },
          "minItems": 1,
          "description": "Facts from AnalysisPool that justify this step"
        },
        "rationale": {
          "type": "string",
          "description": "Human-readable explanation citing EIDs"
        },
        "gated": {
          "type": "boolean",
          "default": false,
          "description": "Requires human approval before execution"
        },
        "retryable": {
          "type": "boolean",
          "default": true,
          "description": "Can be retried on transient failure"
        }
      }
    },
    "Citation": {
      "type": "object",
      "required": ["eid", "factKey"],
      "properties": {
        "eid": {
          "type": "string",
          "description": "Entity ID from AnalysisPool"
        },
        "factKey": {
          "type": "string",
          "description": "Fact key being cited"
        },
        "value": {
          "description": "The fact value at plan time (for audit)"
        }
      }
    },
    "Budget": {
      "type": "object",
      "required": ["maxSteps", "maxMerges", "maxRetries"],
      "properties": {
        "maxSteps": {
          "type": "integer",
          "minimum": 1,
          "description": "Maximum total steps allowed"
        },
        "maxMerges": {
          "type": "integer",
          "minimum": 1,
          "description": "Maximum merge operations allowed"
        },
        "maxRetries": {
          "type": "integer",
          "minimum": 0,
          "description": "Maximum retry attempts per step"
        },
        "timeoutSeconds": {
          "type": "integer",
          "minimum": 0,
          "description": "Maximum execution time (0 = no limit)"
        }
      }
    }
  }
}