{"uid":"cap_8C1wZDuju5qSLfllknlNE","slug":"agent-contract-guard-json-schema-breaking-change-check-ca798ef1","name":"Agent Contract Guard: JSON Schema Breaking Change Check","description":"Compare old and new JSON schemas to detect compatibility issues and schema drift, validate API and MCP tool contract changes, and identify updates that could break clients before deployment or agent adoption.","url":"https://agentguard.weatherriskapi.com/v1/schema/diff?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"new_schema":{"type":"object"},"old_schema":{"type":"object"}}},"responseSchema":{"type":"json","example":{"changes":[{"kind":"property_added","path":"$.properties.age","after":{"type":"number"},"message":"Property 'age' was added","breaking":false},{"kind":"required_added","path":"$.required.age","after":"age","message":"Required field 'age' was added","breaking":true}],"breaking":true,"change_count":2,"breaking_count":1}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_EwowJfT5Od74cYJFwHygE","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Compares two JSON schemas to detect breaking changes and compatibility issues that could break API clients or AI agent tool contracts before deployment.","exampleAgentPrompt":"Check whether my schema update introduces any breaking changes — here's the old schema and the new one with the 'age' field added as required; tell me what changed and whether it would break existing clients.","exampleUseCases":[{"title":"Pre-deployment API contract validation","prompt":"I'm about to deploy a new version of my API — here's the old response schema and the updated one. Can you check if any of the changes would break existing clients?"},{"title":"MCP tool definition compatibility check","prompt":"I updated my MCP tool's input schema to add a new required field. Compare the old and new schema definitions and tell me if this change would break any agents already using the old tool contract."},{"title":"Catching schema drift in CI pipeline","prompt":"Before I merge this PR, compare the baseline JSON schema with the proposed one and flag any breaking changes like removed properties or newly required fields that could cause client failures."}],"resultDescription":"Returns a list of detected changes between the two schemas, each annotated with the change kind (e.g. property_added, required_added), the JSON path affected, a human-readable message, and whether the change is breaking. Also returns aggregate counts of total changes and breaking changes, plus a top-level boolean indicating whether any breaking change was detected.","failureModes":["Invalid or malformed JSON schema input returns a validation error","Missing old_schema or new_schema fields causes a 400 bad request","Schemas with circular references may cause unexpected behavior","Very large or deeply nested schemas may increase response latency","Payment failure (x402) returns a 402 response before processing begins"],"whenToPreferThis":"Choose this endpoint when you need to programmatically detect whether a JSON schema change is backward-compatible before deploying an API update, publishing a new MCP tool definition, or releasing a new agent capability. It is especially valuable in CI/CD pipelines, agent orchestration systems, and API versioning workflows where breaking changes must be caught before clients or agents adopt the new contract.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-17T06:34:25.740Z","isFirstParty":false,"canonicalSlug":"agent-contract-guard-json-schema-breaking-change-check-ca798ef1"}