{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://github.com/occasiolabs/occasio/spec/agent-attestation/v1",
  "title": "Occasio Agent Behavioral Attestation v1",
  "description": "Self-contained, schema-validated commitment to a slice of a Occasio tamper-evident audit chain. Summarises what an AI coding agent did during one governed session (run_id) — every tool call's decision, blocked attempts, redacted secrets, the active policy's digest, and the first/last hashes of the chain segment that backs the claim. Intended to be later wrapped in an in-toto Statement envelope and signed via Sigstore keyless. v1 carries an unsigned variant (signature: null); subsequent versions populate the signature object.",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "schema_version",
    "predicate_type",
    "subject",
    "agent",
    "policy",
    "execution_summary",
    "audit_chain",
    "signature"
  ],
  "properties": {
    "schema_version": {
      "type": "string",
      "const": "1.0.0"
    },
    "predicate_type": {
      "type": "string",
      "const": "https://github.com/occasiolabs/occasio/spec/agent-attestation/v1"
    },
    "subject": {
      "type": "object",
      "additionalProperties": false,
      "required": ["run_id"],
      "properties": {
        "run_id": {
          "type": "string",
          "description": "UUID of the Occasio proxy run that produced the attested events."
        },
        "git_commit": {
          "type": ["string", "null"],
          "description": "Commit the run is bound to. An explicit --git-commit flag (e.g. a CI merge/squash SHA) wins; otherwise defaults to the HEAD recorded in the run's git_state chain rows."
        },
        "files_changed": {
          "type": "array",
          "items": { "type": "string" },
          "description": "Paths modified by the agent during this run, as passed via --files-changed (CI). For chain-sourced evidence see git_state.run_end.changed_files."
        },
        "git_state": {
          "type": "object",
          "additionalProperties": false,
          "description": "Repository state bound to this run, derived from `git_state` audit-chain rows (provenance 'chain'). Present only when the run recorded git_state rows; a verifier re-derives this object from the hash-protected chain and requires byte-equality. run_end may be null when only run-start was captured.",
          "required": ["provenance"],
          "properties": {
            "provenance": { "type": "string", "enum": ["chain"] },
            "run_start": { "oneOf": [{ "type": "null" }, { "$ref": "#/definitions/gitPhaseState" }] },
            "run_end":   { "oneOf": [{ "type": "null" }, { "$ref": "#/definitions/gitPhaseState" }] }
          }
        }
      }
    },
    "agent": {
      "type": "object",
      "additionalProperties": false,
      "required": ["platform", "model", "session_id", "started_at", "ended_at", "wall_time_s"],
      "properties": {
        "platform": {
          "type": "string",
          "description": "Adapter that produced these events (e.g. 'claude-code', 'cline', 'mcp')."
        },
        "model": {
          "type": ["string", "null"],
          "description": "Model ID derived from request rows in the chain slice, if available."
        },
        "session_id": {
          "type": ["string", "null"]
        },
        "started_at": {
          "type": "string",
          "format": "date-time"
        },
        "ended_at": {
          "type": "string",
          "format": "date-time"
        },
        "wall_time_s": {
          "type": "integer",
          "minimum": 0
        }
      }
    },
    "policy": {
      "type": "object",
      "additionalProperties": false,
      "required": ["file_hash", "file_path", "source", "version", "rules_digest"],
      "properties": {
        "file_hash": {
          "type": "string",
          "pattern": "^[0-9a-f]{64}$",
          "description": "SHA-256 of the active policy.yml file bytes (sentinel 0*64 if no file was present)."
        },
        "file_path": {
          "type": ["string", "null"]
        },
        "source": {
          "type": "string",
          "enum": ["user", "default", "unknown", "inferred"],
          "description": "How the file_hash was determined. 'user'/'default'/'unknown' all reflect a policy_loaded event observed inside the run slice. 'inferred' means no such event was found and file_hash was computed from the policy file's current on-disk bytes at attest time — which may differ from what was active during the run. Verifiers SHOULD treat 'inferred' as weaker evidence."
        },
        "version": {
          "type": ["integer", "null"]
        },
        "rules_digest": {
          "type": "object",
          "additionalProperties": false,
          "properties": {
            "deny_paths_count":    { "type": "integer", "minimum": 0 },
            "deny_patterns_count": { "type": "integer", "minimum": 0 },
            "block_secrets":       { "type": "boolean" }
          }
        }
      }
    },
    "execution_summary": {
      "type": "object",
      "additionalProperties": false,
      "required": ["tool_calls", "local", "passed", "blocked", "transformed", "secrets_redacted", "blocked_events"],
      "properties": {
        "tool_calls":      { "type": "integer", "minimum": 0 },
        "local":           { "type": "integer", "minimum": 0 },
        "passed":          { "type": "integer", "minimum": 0 },
        "blocked":         { "type": "integer", "minimum": 0 },
        "transformed":     { "type": "integer", "minimum": 0 },
        "secrets_redacted":{ "type": "integer", "minimum": 0 },
        "blocked_events": {
          "type": "array",
          "items": {
            "type": "object",
            "additionalProperties": false,
            "required": ["tool", "rule", "at_offset_s"],
            "properties": {
              "tool":        { "type": "string" },
              "target":      { "type": ["string", "null"] },
              "rule":        { "type": "string" },
              "at_offset_s": { "type": "integer", "minimum": 0 }
            }
          }
        }
      }
    },
    "audit_chain": {
      "type": "object",
      "additionalProperties": false,
      "required": ["genesis", "first_hash", "last_hash", "event_count", "chain_file", "verifier_url"],
      "properties": {
        "genesis": {
          "type": "string",
          "const": "0000000000000000000000000000000000000000000000000000000000000000"
        },
        "first_hash": {
          "type": ["string", "null"],
          "description": "Hash field of the first attested row (null when event_count == 0).",
          "pattern": "^[0-9a-f]{64}$"
        },
        "last_hash": {
          "type": ["string", "null"],
          "pattern": "^[0-9a-f]{64}$"
        },
        "event_count": {
          "type": "integer",
          "minimum": 0
        },
        "chain_file": {
          "type": "string"
        },
        "verifier_url": {
          "type": "string",
          "format": "uri"
        }
      }
    },
    "signature": {
      "description": "Sigstore keyless / cosign signature. v1 Phase-0 attestations are unsigned (null); Phase 1 populates the object.",
      "oneOf": [
        { "type": "null" },
        {
          "type": "object",
          "additionalProperties": false,
          "required": ["type", "identity", "signed_at"],
          "properties": {
            "type":             { "type": "string", "enum": ["sigstore-cosign-keyless"] },
            "identity":         { "type": "string" },
            "rekor_entry":      { "type": ["string", "null"], "format": "uri" },
            "signed_at":        { "type": "string", "format": "date-time" },
            "envelope_sha256":  { "type": "string", "pattern": "^[0-9a-f]{64}$" }
          }
        }
      ]
    },
    "generated_at": {
      "type": "string",
      "format": "date-time"
    }
  },
  "definitions": {
    "gitPhaseState": {
      "type": "object",
      "additionalProperties": false,
      "required": ["is_repo", "head", "branch", "dirty", "changed_files", "untracked_files", "diff_hash", "digest"],
      "properties": {
        "is_repo":         { "type": "boolean" },
        "head":            { "type": ["string", "null"], "pattern": "^[0-9a-f]{40}$" },
        "branch":          { "type": ["string", "null"] },
        "dirty":           { "type": "boolean" },
        "changed_files":   { "type": "array", "items": { "type": "string" } },
        "untracked_files": { "type": "array", "items": { "type": "string" } },
        "diff_hash":       { "type": ["string", "null"], "pattern": "^[0-9a-f]{64}$" },
        "digest":          { "type": ["string", "null"], "pattern": "^[0-9a-f]{64}$" }
      }
    }
  }
}