output-contract-enforcer

name	output-contract-enforcer
license	Apache-2.0
description	Validates that a DAG node's output matches its declared JSON schema before passing to downstream nodes. The glue that makes multi-agent DAGs reliable. Use when checking output contract compliance, generating validation schemas from descriptions, or debugging contract mismatches between nodes. Activate on "validate output", "output contract", "schema validation", "contract mismatch", "output doesn't match". NOT for content quality assessment (use dag-quality), skill grading (use skill-grader), or general JSON schema work outside DAG context.
allowed-tools	Read,Write,Edit,Grep
argument-hint	[output-json] [schema]
metadata	{"tags":["output","contract","enforcer","validate-output","output-contract"],"pairs-with":[{"skill":"task-decomposer","reason":"Decomposed tasks define the output schemas that the enforcer validates between nodes"},{"skill":"human-gate-designer","reason":"Human gate inputs/outputs need the same schema validation as automated node outputs"},{"skill":"typescript-advanced-patterns","reason":"Branded types and Zod schemas implement runtime output contract validation in TypeScript"}]}
category	Agent & Orchestration
tags	["contracts","validation","output-quality","schema","enforcement"]

Output Contract Enforcer

Validates that a DAG node's output matches its declared JSON schema before passing to downstream nodes. The glue that makes multi-agent DAGs reliable. Without this, downstream nodes receive unpredictable input and the DAG breaks.

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When to Use

✅ Use for:

• Validating a node's output against its declared schema
• Generating output schemas from natural-language output descriptions
• Debugging why a downstream node rejected its input
• Ensuring contract compatibility between connected nodes

❌ NOT for:

• Assessing content quality or correctness (use dag-quality)
• Grading skill quality (use skill-grader)
• General JSON schema work outside DAG context

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Validation Process

flowchart TD
  O[Node output] --> P[Parse as JSON]
  P -->|Parse error| E1[FAIL: Not valid JSON]
  P -->|Valid JSON| S[Check against schema]
  S --> R{Required fields?}
  R -->|Missing| E2[FAIL: Missing required field X]
  R -->|Present| T{Type check?}
  T -->|Wrong type| E3[FAIL: Field X expected string, got number]
  T -->|Correct| C{Constraints?}
  C -->|Violated| E4[FAIL: Field X violates constraint Y]
  C -->|Met| V[PASS: Contract satisfied]

What Gets Checked

Check	Example	Failure Message
JSON parseable	{broken json	"Output is not valid JSON"
Required fields	status missing	"Missing required field: status"
Field types	status: 42 (expected string)	"Field 'status' expected string, got number"
Enum values	status: "maybe"	"Field 'status' must be one of: pass, warn, fail"
String constraints	summary: "" (minLength: 1)	"Field 'summary' must have minLength 1"
Number constraints	score: 1.5 (maximum: 1.0)	"Field 'score' must be ≤ 1.0"
Array constraints	items: [] (minItems: 1)	"Field 'items' must have at least 1 item"