{"uid":"cap_Tig76OA_nyLjgoD1qm7Z1","slug":"babydov-postcondition-verify-http-response-assertion-evidence-247cc53b","name":"BABYDOV Postcondition Verify — HTTP Response Assertion & Evidence","description":"Low-cost x402 APIs for autonomous agents: payment preflight, web evidence, bounty intelligence, source evidence and public-web extraction.","url":"https://vps-62-120.cloudhosting.lv:8443/postcondition-verify?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"queryParams":{"type":"object","required":["url"],"properties":{"url":{"type":"string","format":"uri"},"logic":{"enum":["all","any"],"type":"string"},"equals":{"type":"string","maxLength":500},"contains":{"type":"string","maxLength":200},"json_key":{"type":"string","maxLength":120},"not_contains":{"type":"string","maxLength":200},"expect_status":{"type":"integer","maximum":599,"minimum":100},"max_redirects":{"type":"integer","maximum":10,"minimum":0},"max_latency_ms":{"type":"number","maximum":60000,"exclusiveMinimum":0},"expected_sha256":{"type":"string","maxLength":64,"minLength":64},"final_url_contains":{"type":"string","maxLength":200},"content_type_contains":{"type":"string","maxLength":120}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"logic":"all","passed":true,"check_count":2,"payment_sent":false,"schema_version":"babydov.postcondition_verify.v2","evidence_sha256":"...","verification_id":"pv_...","failed_check_count":0}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.003","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"registry","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":"$0.003/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.003","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_LhM3KIzNUgTHWnTyo-6aJ","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.003","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Verifies that a live HTTP endpoint satisfies one or more configurable postconditions (status code, body content, JSON key, SHA-256 hash, redirect, latency) and returns tamper-evident evidence with a verification ID.","exampleAgentPrompt":"Check that https://api.example.com/health returns a 200 status and that the response body contains the string 'ok' — I need tamper-evident proof with a verification ID that all conditions passed.","exampleUseCases":[{"title":"Bounty release precondition check","prompt":"Before I release payment on this bug bounty, verify that https://bugtracker.example.com/issues/1042 returns a 200 and contains the text 'resolved' — I need a verifiable evidence record with a SHA-256 hash I can audit later."},{"title":"Confirm API endpoint health before agent action","prompt":"Check that https://payments.myapp.io/status responds with a 200 and that the JSON response has the key 'healthy' — use 'all' logic so I know both conditions passed, and give me a verification ID."},{"title":"Verify file integrity at a public URL","prompt":"I need to confirm that the file at https://releases.myproject.org/v2.1.0/artifact.zip has an SHA-256 hash of a3f1b2c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2 and that the server responds within 5000 milliseconds — give me tamper-evident proof."}],"resultDescription":"A JSON object containing: a 'passed' boolean (overall result), 'check_count' (number of assertions evaluated), 'failed_check_count', 'logic' (all/any), a unique 'verification_id' (prefixed pv_), an 'evidence_sha256' hash of the observed response for auditability, 'payment_sent' flag, and 'schema_version'. Enables agents to hold cryptographic evidence that a URL satisfied specific conditions at a point in time.","failureModes":["Target URL unreachable or DNS resolution failure — verification fails with network error","Target URL returns unexpected status code — check fails, failed_check_count incremented","Response body does not contain expected string — assertion fails","SHA-256 hash mismatch — hash check fails","Response latency exceeds max_latency_ms — latency check fails","Max redirects exceeded — redirect check fails","Malformed URL in queryParams.url — input validation error","logic enum value not in ['all','any'] — schema validation error","Missing required 'url' in queryParams — 400 bad request","x402 payment not satisfied — 402 payment required before response"],"whenToPreferThis":"Choose this endpoint when an AI agent needs cryptographically auditable, tamper-evident proof that a live HTTP resource satisfies specific postconditions — such as before releasing a bounty, confirming a deployment went live, or validating a third-party API contract. It is superior to a simple HTTP fetch when you need a verifiable evidence record (SHA-256 + verification ID), combinatorial logic (all/any) over multiple assertions, or low-cost autonomous verification without standing up your own infrastructure. Prefer alternatives if you need to extract or transform the response body rather than just assert conditions on it.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T12:39:35.708Z","isFirstParty":false,"canonicalSlug":"babydov-postcondition-verify-http-response-assertion-evidence-247cc53b"}