{ "openapi": "3.1.1", "info": { "title": "CDN Behaviour Explorer API", "version": "1.0.0", "summary": "Which CDN serves a URL, whether it caches it (HIT/MISS, Age, TTL) and how, from two requests.", "description": "Every endpoint performs the same calculation as the human page and returns inputs, result, units, assumptions, sources, warnings and computedAt. MCP endpoint: /mcp." }, "servers": [ { "url": "https://cdnbehaviorexplorer.usefulweb.site" } ], "paths": { "/api/v1/calculate": { "post": { "operationId": "calculate", "summary": "Which CDN serves a URL, whether it caches it (HIT/MISS, Age, TTL) and how, from two requests.", "description": "Sends two consecutive requests to a public URL (or reads two pasted header sets) and compares them: CDN detection from vendor headers (Cloudflare, CloudFront, Fastly, Akamai, Vercel, Netlify, Bunny, Azure, Google), edge cache status HIT/MISS/EXPIRED, Age progression, edge location, shared-cache TTL, Vary and compression. Only this server's vantage point is used; there is no multi-region comparison.\n\nMethodology:\n- Live mode: two GET requests in a row through the SSRF-guarded fetcher (body capped at 64 KiB each), identical request headers.\n- CDN detection from vendor headers: cf-ray/cf-cache-status (Cloudflare), x-amz-cf-id/x-amz-cf-pop (CloudFront), x-served-by cache-xxx/x-fastly-request-id (Fastly), akamai-grn/x-akamai-*/AkamaiGHost (Akamai), x-vercel-id, x-nf-request-id, BunnyCDN, x-azure-ref, Via: google.\n- Cache status from the vendor header or RFC 9211 Cache-Status (the last listed cache is closest to the client); Age (RFC 9111 §5.1) growing between requests means one stored copy answered both.\n- TTL: CDN-Cache-Control / Surrogate-Control > s-maxage > max-age > Expires − Date. Browser TTL is max-age.\n- Region comparison is not available: tools run from one server. HeaderLens has multi-region probe agents, but they are not wired into tools.", "tags": [ "infrastructure" ], "x-mcp-tool": "cdn_behavior_explorer", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CdnBehaviorExplorerInput" }, "examples": { "example1": { "summary": "Cloudflare MISS then HIT (pasted)", "value": { "mode": "paste", "headersFirst": "HTTP/2 200\ndate: Mon, 12 Oct 2026 10:00:00 GMT\ncontent-type: text/html; charset=utf-8\ncontent-encoding: br\ncache-control: public, max-age=60, s-maxage=3600\netag: W/\"abc123\"\nvary: Accept-Encoding\ncf-cache-status: MISS\nage: 0\ncf-ray: 8d2f1a2b3c4d5e6f-FRA\nserver: cloudflare\nalt-svc: h3=\":443\"; ma=86400", "headersSecond": "HTTP/2 200\ndate: Mon, 12 Oct 2026 10:00:05 GMT\ncontent-type: text/html; charset=utf-8\ncontent-encoding: br\ncache-control: public, max-age=60, s-maxage=3600\netag: W/\"abc123\"\nvary: Accept-Encoding\ncf-cache-status: HIT\nage: 5\ncf-ray: 8d2f1a2c4e5f6a7b-FRA\nserver: cloudflare\nalt-svc: h3=\":443\"; ma=86400" } } } } } }, "responses": { "200": { "description": "Calculation result envelope.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/CdnBehaviorExplorerResult" } } } }, "400": { "description": "Malformed JSON body.", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } }, "422": { "description": "Invalid input (see errors[]).", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } }, "429": { "description": "Rate limit exceeded (see Retry-After).", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } } } } }, "/api/v1/tool": { "get": { "operationId": "getToolDefinition", "summary": "Inputs, output schema and examples for this tool", "responses": { "200": { "description": "Tool definition.", "content": { "application/json": { "schema": { "type": "object" } } } } } } } }, "components": { "schemas": { "Problem": { "type": "object", "description": "RFC 9457 problem details. 422 responses include per-field `errors`.", "required": [ "type", "title", "status", "detail" ], "properties": { "type": { "type": "string" }, "title": { "type": "string" }, "status": { "type": "integer" }, "detail": { "type": "string" }, "code": { "type": "string" }, "errors": { "type": "array", "items": { "type": "object", "required": [ "field", "message" ], "properties": { "field": { "type": "string" }, "message": { "type": "string" } } } } } }, "CdnBehaviorExplorerInput": { "type": "object", "additionalProperties": false, "properties": { "mode": { "title": "Mode", "type": "string", "enum": [ "live", "paste" ], "default": "live" }, "url": { "title": "URL (live mode)", "type": "string", "format": "uri" }, "headersFirst": { "title": "Response headers of request 1 (paste mode)", "type": "string", "maxLength": 30000 }, "headersSecond": { "title": "Response headers of request 2 (paste mode)", "type": "string", "maxLength": 30000 } }, "required": [] }, "CdnBehaviorExplorerResult": { "type": "object", "additionalProperties": false, "required": [ "schemaVersion", "tool", "computedAt", "inputs", "summary", "result", "units", "assumptions", "sources", "warnings", "presentation", "links" ], "properties": { "schemaVersion": { "type": "string", "const": "1.0" }, "tool": { "type": "object", "additionalProperties": false, "required": [ "id", "name", "version" ], "properties": { "id": { "type": "string" }, "name": { "type": "string" }, "version": { "type": "string" } } }, "computedAt": { "type": "string", "format": "date-time" }, "inputs": { "type": "object", "description": "Normalised inputs actually used, including applied defaults." }, "summary": { "type": "string" }, "result": { "type": "object", "additionalProperties": false, "required": [ "mode", "url", "cdns", "requests", "verdict", "explanation", "ageDelta", "dateDelta", "etagStable", "caching", "regionComparison" ], "properties": { "mode": { "type": "string", "enum": [ "live", "paste" ] }, "url": { "type": [ "string", "null" ] }, "cdns": { "type": "array", "items": { "type": "object", "additionalProperties": false, "required": [ "cdn", "confidence", "evidence" ], "properties": { "cdn": { "type": "string" }, "confidence": { "type": "string", "enum": [ "high", "medium", "low" ] }, "evidence": { "type": "string" } } } }, "requests": { "type": "array", "items": { "type": "object", "additionalProperties": false, "required": [ "status", "cacheStatus", "cacheHeader", "age", "date", "etag", "pop", "encoding" ], "properties": { "status": { "type": [ "integer", "null" ] }, "cacheStatus": { "type": "string" }, "cacheHeader": { "type": [ "string", "null" ] }, "age": { "type": [ "integer", "null" ] }, "date": { "type": [ "string", "null" ] }, "etag": { "type": [ "string", "null" ] }, "pop": { "type": [ "string", "null" ] }, "encoding": { "type": [ "string", "null" ] } } } }, "verdict": { "type": "string", "enum": [ "edge-cached", "warmed-on-second-request", "not-cached-at-edge", "bypassed", "no-cdn-detected", "inconclusive" ] }, "explanation": { "type": "string" }, "ageDelta": { "type": [ "integer", "null" ] }, "dateDelta": { "type": [ "integer", "null" ] }, "etagStable": { "type": [ "boolean", "null" ] }, "caching": { "type": "object", "additionalProperties": false, "required": [ "verdict", "cacheControl", "cdnCacheControl", "surrogateControl", "sharedTtl", "browserTtl", "vary" ], "properties": { "verdict": { "type": "string" }, "cacheControl": { "type": [ "string", "null" ] }, "cdnCacheControl": { "type": [ "string", "null" ] }, "surrogateControl": { "type": [ "string", "null" ] }, "sharedTtl": { "type": [ "integer", "null" ] }, "browserTtl": { "type": [ "integer", "null" ] }, "vary": { "type": [ "string", "null" ] } } }, "regionComparison": { "type": "string" } } }, "units": { "type": "object", "additionalProperties": { "type": "string" } }, "assumptions": { "type": "array", "items": { "type": "string" } }, "sources": { "type": "array", "items": { "type": "object", "additionalProperties": false, "required": [ "title" ], "properties": { "title": { "type": "string" }, "url": { "type": "string" }, "publisher": { "type": "string" }, "retrievedAt": { "type": "string" }, "note": { "type": "string" } } } }, "warnings": { "type": "array", "items": { "type": "string" } }, "presentation": { "type": "array", "items": { "type": "object" }, "description": "Display blocks used by the human page (same data)." }, "links": { "type": "object", "additionalProperties": false, "required": [ "human", "api", "openapi", "methodology" ], "properties": { "human": { "type": "string", "format": "uri" }, "api": { "type": "string", "format": "uri" }, "openapi": { "type": "string", "format": "uri" }, "methodology": { "type": "string", "format": "uri" } } } } } } } }