---
title: "Replay/diff alias for a stored decision"
method: POST
path: "/api/decision/{decision_id}/diff"
tags: ["Decision Protocol"]
---

# Replay/diff alias for a stored decision

`POST /api/decision/{decision_id}/diff`

## Request

- Base URL: `https://www.decide.fyi`
- URL: `https://www.decide.fyi/api/decision/{decision_id}/diff`
- Auth: API key in header `x-api-key`

Forces current-mode replay so callers can compare the stored decision against the current runtime or a supplied current-mode input override.

## Path parameters

- `decision_id` string, required

## Headers

- `x-decision-response-view` 'minimal' | 'standard' | 'full'

## Response `200`

Replay/diff summary and current decision projection

- ReplayResult
  - `ok` boolean, required
  - `replay` ReplaySummary, required
    - `mode` 'historical' | 'current', required
    - `source_decision_id` string, required
    - `replay_decision_id` string, required
    - `changed` boolean, required
    - `semantic_match` boolean, required
    - `historical_reproduction` boolean, required
    - `rulebook_hash` string, nullable
    - `adapter_manifest_hash` string, nullable
    - `evaluator_version` string, nullable
    - `previous` object, required
    - `current` object, required
    - `diff` object, required
      - `output_changed` boolean
      - `verdict_changed` boolean
      - `policy_version_changed` boolean
      - `semantic_changed` boolean
  - `decision` DecisionRecord, required
    - `decision_protocol_version` 'decision_protocol_v1', required
    - `decision_record_version` 'decision_record_v1', required
    - `response_view` 'minimal' | 'standard' | 'full'
    - `decision_id` string, required
    - `request_id` string, required
    - `idempotency_key` string
    - `c` string
    - `v` string
    - `verdict` string, required
    - `application_verdict` string: Purpose-specific bounded verdict produced by Rulebook v1, such as APPROVE, BLOCK, REVIEW, or NEEDS_INPUT.
    - `evaluator_version` string: Versioned evaluator that produced the binding rulebook result.
    - `rulebook_contract` RulebookContract
      - `schema_version` 'rulebook_v1', required
      - `schema_url` 'https://api.decide.fyi/schemas/rulebook-v1.schema.json', required
      - `schema_hash` string, required: SHA-256 hash of the published Rulebook v1 JSON Schema enforced by the runtime.
      - `evaluator_version` 'decide_rulebook_v1', required
    - `action` string
    - `reason_code` string
    - `matched_rule_id` string, nullable
    - `rulebook` object
      - `schema_version` 'rulebook_v1'
      - `id` string
      - `version` string
      - `hash` string
    - `rulebook_registry` RulebookRegistryMetadata
      - `rulebook_registry_version` 'decision_rulebook_registry_v1', required
      - `schema_version` 'rulebook_v1', required
      - `rulebook_id` string, required
      - `version` string, required
      - `hash` string, required
      - `evaluator_version` string, required
      - `trusted_adapter` TrustedAdapterDependency
        - `manifest_version` 'trusted_adapter_manifest_v1', required
        - `adapter_id` string, required
        - `version` string, required
        - `implementation_revision` string, required
        - `implementation_hash` string, required
        - `manifest_hash` string, required
      - `hash_algorithm` 'sha256', required
      - `canonicalization` 'json.sort_deep.v1', required
      - `scope_hash` string, required
      - `registry_attestation` RegistryAttestation, required
        - `registry_attestation_version` 'decision_registry_attestation_v1', required
        - `status` 'signed' | 'unsigned', required
        - `attestation_hash` string, required
        - `key_id` string
        - `signature_algorithm` 'ed25519'
        - `signature` string
        - `public_key` string
        - `public_key_fingerprint` string
      - `registered_at` string, date-time, required
    - `runtime_binding` RuntimeBinding
      - `production_core` 'hybrid_declarative_rulebook_with_trusted_adapters', required
      - `binding_mode` 'direct_declarative_rulebook' | 'trusted_adapter_facts_then_declarative_rulebook', required
      - `verdict_authority` 'declarative_rulebook', required
      - `adapter_authority` 'facts_only'
      - `customer_supplied_code` 'rejected', required
    - `trusted_adapter` TrustedAdapterAttestation
      - `manifest_version` 'trusted_adapter_manifest_v1', required
      - `adapter_id` string, required
      - `version` string, required
      - `implementation_revision` string, required
      - `implementation_hash` string, required
      - `manifest_hash` string, required
      - `input_hash` string, required
      - `output_hash` string, required
      - `execution_isolation` 'worker_thread_one_shot_v1', required
      - `capability_enforcement` 'ambient_capability_deny_v2', required
      - `execution_timeout_ms` integer, required
    - `adapter_facts` object: Schema-validated facts emitted by the pinned trusted adapter before Rulebook v1 evaluation.
    - `action_binding` ActionBinding
      - `actor` string
      - `system` string
      - `resource` string
      - `proposed_action` string
      - `subject` string
      - `amount` string
      - `currency` string
      - `target_system` string
      - `target_object_id` string
      - `mutation` string
      - `expires_at` string
      - `execution_state` string
      - `execution_id` string
    - `evidence` string[]
    - `evidence_manifest` EvidenceManifest
      - `codes` string[]
      - `sources` EvidenceSource[]
        - `id` string
        - `type` string
        - `vendor` string
        - `title` string
        - `url` string
        - `policy_ref` string
        - `observed_at` string
        - `retrieval_id` string
        - `hash` string
        - `snapshot_hash` string
        - `content_hash` string
        - `version` string
    - `policy_id` string
    - `policy_version` string
    - `policy_hash` string
    - `source_hash` string: Backend lineage hash returned in the full Decision Record response when the upstream decision engine supplies it.
    - `policy_bundle` PolicyBundle
      - `id` string
      - `version` string
      - `hash` string
      - `hash_algorithm` string
      - `canonicalization` string
      - `source` string
      - `status` string
      - `effective_at` string
      - `deprecated_at` string
      - `changelog` string
      - `content_hash` string
    - `policy_bundle_hash` string
    - `confidence` DecisionConfidence
      - `ok` boolean, required
      - `decision_confidence_version` 'decision_confidence_v1', required
      - `generated_at` string
      - `source` 'decision_outcomes'
      - `scope` 'caller_api_key'
      - `decision_id` string, nullable
      - `policy_id` string, nullable
      - `policy_version` string, nullable
      - `verdict` string
      - `action` string, nullable
      - `score` number, required
      - `level` 'high' | 'medium' | 'low' | 'weak' | 'insufficient_data', required
      - `based_on` integer
      - `similar_decisions` integer
      - `policy_stability` 'high' | 'medium' | 'low' | 'insufficient_data'
      - `recommendation` 'collect_more_outcomes' | 'high_confidence_proceed' | 'high_confidence_block' | 'high_confidence_review' | 'proceed_with_monitoring' | 'route_for_review' | 'monitor', required
      - `metrics` object
      - `baseline` object
      - `data_quality` object
      - `reasons` object[]
      - `confidence_hash` string, required
    - `decision_confidence` DecisionConfidence
      - `ok` boolean, required
      - `decision_confidence_version` 'decision_confidence_v1', required
      - `generated_at` string
      - `source` 'decision_outcomes'
      - `scope` 'caller_api_key'
      - `decision_id` string, nullable
      - `policy_id` string, nullable
      - `policy_version` string, nullable
      - `verdict` string
      - `action` string, nullable
      - `score` number, required
      - `level` 'high' | 'medium' | 'low' | 'weak' | 'insufficient_data', required
      - `based_on` integer
      - `similar_decisions` integer
      - `policy_stability` 'high' | 'medium' | 'low' | 'insufficient_data'
      - `recommendation` 'collect_more_outcomes' | 'high_confidence_proceed' | 'high_confidence_block' | 'high_confidence_review' | 'proceed_with_monitoring' | 'route_for_review' | 'monitor', required
      - `metrics` object
      - `baseline` object
      - `data_quality` object
      - `reasons` object[]
      - `confidence_hash` string, required
    - `confidence_hash` string
    - `input_hash` string
    - `output_hash` string
    - `record_hash` string, required: Tamper-evident hash of the normalized Decision Record v1 envelope, including binding application verdict, reason, matched rule, rulebook lineage, registry attestation, trusted adapter attestation, and adapter facts when present.
    - `receipt_hash` string, required: Portable receipt hash over record_hash plus input/output, policy, action-binding, and evidence-manifest proof hashes.
    - `receipt_key_id` string
    - `receipt_signature` string
    - `receipt_signature_algorithm` 'hmac-sha256' | 'ed25519'
    - `receipt_public_key` string
    - `receipt_public_key_fingerprint` string
    - `integrity` Integrity
      - `canonicalization` string
      - `decision_protocol_version` string
      - `hash_algorithm` string
      - `input_hash` string
      - `output_hash` string
      - `policy_hash` string
      - `policy_bundle_hash` string
      - `record_hash` string
      - `receipt_hash` string
      - `replay_url` string
      - `verify_url` string
      - `signature` object
    - `verify_url` string, required
    - `replay_url` string, required
    - `created_at` string
    - `audit_chain` AuditChain
      - `decision_chain_version` 'decision_chain_v1', required
      - `chain_id` string, required
      - `chain_position` integer, required
      - `previous_link_hash` string, nullable
      - `leaf_hash` string, required
      - `merkle_root` string, required
      - `merkle_strategy` 'rolling_sha256_pair_v1'
      - `link_hash` string, required
      - `chain_url` string
      - `created_at` string
      - `entry_type` string
    - `chain_url` string

---

[API](https://skmtc.dev/decide/apis/decide-decision-api.md) · [All operations](https://skmtc.dev/decide/apis/decide-decision-api/llms.txt) · [OpenAPI document](https://skmtc.dev/decide/apis/decide-decision-api/revisions/caf1d3069dfd?raw)