{
  "schema_version": "1",
  "generated_at": "2026-10-20T00:00:00Z",
  "tag": "interop",
  "count": 27,
  "entries": [
    {
      "id": "ietf-draft-httpauth-payment",
      "title": "The \"Payment\" HTTP Authentication Scheme (draft-httpauth-payment-01)",
      "publisher": "IETF Datatracker",
      "authors": [
        "Brendan Ryan",
        "Jake Moxey",
        "Tom Meagher",
        "Jeff Weinstein",
        "Steve Kaliski"
      ],
      "date_published": "2026-09-09",
      "url": "https://datatracker.ietf.org/doc/draft-httpauth-payment/",
      "type": "spec",
      "category": "payments",
      "summary": "Internet-Draft defining a payment-method-agnostic HTTP authentication scheme for 402 flows: the server sends WWW-Authenticate: Payment with challenge parameters and the client retries with Authorization: Payment and a credential. Revision 01 is dated 2026-09-09 and is an active draft, not an RFC.",
      "tags": [
        "m2m-payments",
        "http",
        "standards",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261014085833/https://datatracker.ietf.org/doc/draft-httpauth-payment/"
    },
    {
      "id": "x402-bazaar-extension-docs",
      "title": "Bazaar (Discovery Layer)",
      "publisher": "x402 (docs.x402.org)",
      "authors": [],
      "date_published": null,
      "url": "https://docs.x402.org/extensions/bazaar",
      "type": "docs",
      "category": "payments",
      "summary": "Documentation for the x402 Bazaar extension. Facilitators can catalog payable HTTP endpoints and MCP tools and expose list and search discovery endpoints, so agents can find x402 resources together with their input/output schemas and prices.",
      "tags": [
        "x402",
        "directory",
        "m2m-payments",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261005104256/https://docs.x402.org/extensions/bazaar"
    },
    {
      "id": "x402-bazaar-spec-github",
      "title": "specs/extensions/bazaar.md",
      "publisher": "GitHub (x402 Foundation)",
      "authors": [],
      "date_published": null,
      "url": "https://github.com/x402-foundation/x402/blob/main/specs/extensions/bazaar.md",
      "type": "spec",
      "category": "payments",
      "summary": "Normative spec for the Bazaar extension. It covers facilitator validation of the discovery info and the optional GET /discovery/resources and /discovery/search APIs, which filter by type, payTo, scheme and network and paginate with offsets or cursors.",
      "tags": [
        "x402",
        "directory",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": null
    },
    {
      "id": "x402scan-discovery-spec",
      "title": "x402scan Discovery & Registration Spec",
      "publisher": "GitHub (Merit Systems)",
      "authors": [],
      "date_published": null,
      "url": "https://github.com/Merit-Systems/x402scan/blob/main/docs/DISCOVERY.md",
      "type": "spec",
      "category": "payments",
      "summary": "Describes how x402scan discovers paid endpoints. It reads OpenAPI first, with per-operation x-payment-info pricing and a declared 402 response, and falls back to a /.well-known/x402 resource list. The live 402 challenge overrides static metadata.",
      "tags": [
        "x402",
        "openapi",
        "interop",
        "directory"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20260130040413/https://github.com/Merit-Systems/x402scan/blob/main/docs/DISCOVERY.md"
    },
    {
      "id": "mpp-dev",
      "title": "MPP: Machine Payments Protocol",
      "publisher": "mpp.dev",
      "authors": [],
      "date_published": null,
      "url": "https://mpp.dev/",
      "type": "spec",
      "category": "payments",
      "summary": "Documentation hub for the Machine Payments Protocol, which standardizes HTTP 402 challenges, credentials and receipts for machine payments across methods including stablecoins, cards and Lightning. It publishes llms.txt, per-page Markdown, an MCP server card and an Agent Skills index.",
      "tags": [
        "m2m-payments",
        "stablecoins",
        "lightning",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261006012625/https://mpp.dev/"
    },
    {
      "id": "mpp-discovery",
      "title": "Discovery (MPP)",
      "publisher": "mpp.dev",
      "authors": [],
      "date_published": null,
      "url": "https://mpp.dev/advanced/discovery",
      "type": "docs",
      "category": "payments",
      "summary": "Explains how an MPP server advertises payment terms ahead of time in an OpenAPI 3.1 document, with paid operations annotated by x-payment-info, while the runtime 402 challenge remains authoritative.",
      "tags": [
        "m2m-payments",
        "openapi",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261003141031/https://mpp.dev/advanced/discovery"
    },
    {
      "id": "ucp-dev",
      "title": "Universal Commerce Protocol (UCP)",
      "publisher": "Universal Commerce Protocol",
      "authors": [],
      "date_published": null,
      "url": "https://ucp.dev/",
      "type": "spec",
      "category": "payments",
      "summary": "Site for the Universal Commerce Protocol, an open agentic-commerce standard.",
      "tags": [
        "interop",
        "agents",
        "standards"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261016171038/https://ucp.dev/"
    },
    {
      "id": "ucp-github",
      "title": "Universal-Commerce-Protocol/ucp",
      "publisher": "GitHub (Universal Commerce Protocol)",
      "authors": [],
      "date_published": null,
      "url": "https://github.com/universal-commerce-protocol/ucp",
      "type": "repo",
      "category": "payments",
      "summary": "Specification and documentation repository for the Universal Commerce Protocol.",
      "tags": [
        "interop",
        "standards"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20260920171720/https://github.com/Universal-Commerce-Protocol/ucp"
    },
    {
      "id": "mcp-sep-2127-server-cards",
      "title": "SEP-2127: MCP Server Cards - HTTP Server Discovery",
      "publisher": "GitHub (Model Context Protocol)",
      "authors": [],
      "date_published": "2026-10-06",
      "url": "https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2127",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Merged MCP enhancement proposal for pre-connection discovery of remote MCP servers through Server Cards, advertised from a domain-level /.well-known/ai-catalog.json. It supersedes the earlier SEP-1649 approach. The server-card schema is still marked experimental.",
      "tags": [
        "mcp",
        "interop",
        "standards"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261015061132/https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2127"
    },
    {
      "id": "mcp-specification-2026-07-28",
      "title": "Specification - Model Context Protocol (Version 2026-07-28)",
      "publisher": "Model Context Protocol",
      "authors": [],
      "date_published": "2026-07-28",
      "url": "https://modelcontextprotocol.io/specification/2026-07-28",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Latest dated version of the Model Context Protocol specification, covering architecture, base protocol, lifecycle, transports, authorization and client and server features. The version identifier is the date.",
      "tags": [
        "mcp",
        "interop",
        "tools"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261020010758/https://modelcontextprotocol.io/specification/2026-07-28"
    },
    {
      "id": "ietf-dns-aid",
      "title": "DNS for AI Discovery (draft-mozleywilliams-dnsop-dnsaid-02)",
      "publisher": "IETF Datatracker",
      "authors": [
        "Jim Mozley",
        "Nic Williams",
        "Behcet Sarikaya",
        "Roland Schott",
        "Jeffrey Damick"
      ],
      "date_published": "2026-05-27",
      "url": "https://datatracker.ietf.org/doc/draft-mozleywilliams-dnsop-dnsaid/",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Internet-Draft for publishing AI agent endpoints and capability metadata in DNS using SVCB records and DNS-SD-style indexes, with DNSSEC/DANE for validation. Active individual draft, revision 02.",
      "tags": [
        "interop",
        "identity",
        "standards"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20260923065951/https://datatracker.ietf.org/doc/draft-mozleywilliams-dnsop-dnsaid/"
    },
    {
      "id": "cloudflare-agent-readiness",
      "title": "Introducing the Agent Readiness score. Check to see if your site is agent-ready",
      "publisher": "Cloudflare Blog",
      "authors": [],
      "date_published": "2026-04-17",
      "url": "https://blog.cloudflare.com/agent-readiness",
      "type": "announcement",
      "category": "agent-protocols",
      "summary": "Cloudflare post introducing an Agent Readiness score and the isitagentready.com scanner, which checks emerging standards such as llms.txt, Markdown negotiation, Content Signals, RFC 9727 API catalogs, MCP Server Cards, A2A Agent Cards, Agent Skills and the x402/MPP commerce protocols.",
      "tags": [
        "interop",
        "web-agents",
        "standards"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261006003600/https://blog.cloudflare.com/agent-readiness/"
    },
    {
      "id": "mcp-specification-2025-06-18",
      "title": "Specification - Model Context Protocol (Version 2025-06-18)",
      "publisher": "Model Context Protocol",
      "authors": [],
      "date_published": "2025-06-18",
      "url": "https://modelcontextprotocol.io/specification/2025-06-18",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Earlier dated revision of the MCP specification, covering authorization, transports, roots, sampling, elicitation, prompts and resources.",
      "tags": [
        "mcp",
        "interop",
        "tools"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20260924095810/https://modelcontextprotocol.io/specification/2025-06-18"
    },
    {
      "id": "llms-txt",
      "title": "The /llms.txt file, v2",
      "publisher": "llmstxt.org",
      "authors": [
        "Jeremy Howard"
      ],
      "date_published": "2024-09-03",
      "url": "https://llmstxt.org/",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Proposal to standardise an /llms.txt file that gives agents information about how to use a website. The page was last modified on 10 August 2026.",
      "tags": [
        "llms-txt",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261016034533/https://llmstxt.org/"
    },
    {
      "id": "openapi-3-1-0",
      "title": "OpenAPI Specification v3.1.0",
      "publisher": "OpenAPI Initiative",
      "authors": [],
      "date_published": "2021-02-15",
      "url": "https://spec.openapis.org/oas/v3.1.0.html",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Standard, programming-language-agnostic interface description for HTTP APIs, widely used to describe tools and APIs for programmatic consumers.",
      "tags": [
        "openapi",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261008125912/https://spec.openapis.org/oas/v3.1.0.html"
    },
    {
      "id": "a2a-protocol-specification",
      "title": "Agent2Agent (A2A) Protocol Specification",
      "publisher": "A2A Protocol",
      "authors": [],
      "date_published": null,
      "url": "https://a2a-protocol.org/latest/specification/",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Official A2A specification (latest released version 1.0.0), an open standard for communication and interoperability between independent, potentially opaque AI agent systems built on different frameworks or by different vendors.",
      "tags": [
        "a2a",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261009134313/https://a2a-protocol.org/latest/specification/"
    },
    {
      "id": "mcp-registry",
      "title": "Official MCP Registry",
      "publisher": "Model Context Protocol",
      "authors": [],
      "date_published": null,
      "url": "https://registry.modelcontextprotocol.io/",
      "type": "directory",
      "category": "agent-protocols",
      "summary": "Official registry of MCP servers with an unauthenticated read API (GET /v0.1/servers) supporting cursor pagination, name search and updated_since for incremental sync by downstream aggregators.",
      "tags": [
        "mcp",
        "directory",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261009210501/https://registry.modelcontextprotocol.io/"
    },
    {
      "id": "mcp-ext-server-card",
      "title": "modelcontextprotocol/ext-server-card",
      "publisher": "GitHub (Model Context Protocol)",
      "authors": [],
      "date_published": null,
      "url": "https://github.com/modelcontextprotocol/experimental-ext-server-card",
      "type": "repo",
      "category": "agent-protocols",
      "summary": "Experimental extension that holds the TypeScript and JSON Schema source for MCP Server Cards. A card describes a remote server's identity and transport endpoints; tools are listed at runtime, not on the card.",
      "tags": [
        "mcp",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": null
    },
    {
      "id": "ai-catalog",
      "title": "AI Catalog",
      "publisher": "AI Catalog (Agent-Card)",
      "authors": [],
      "date_published": null,
      "url": "https://ai-catalog.io/",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Cross-protocol draft standard for a typed, nestable JSON catalog that lists heterogeneous AI artifacts (MCP servers, A2A agents, datasets and more) for discovery. It is developed by members of several AI protocol communities.",
      "tags": [
        "interop",
        "mcp",
        "a2a",
        "standards"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20260919213800/https://ai-catalog.io/"
    },
    {
      "id": "a2a-agent-discovery",
      "title": "Agent Discovery (A2A Protocol)",
      "publisher": "A2A Protocol",
      "authors": [],
      "date_published": null,
      "url": "https://a2a-protocol.org/latest/topics/agent-discovery/",
      "type": "docs",
      "category": "agent-protocols",
      "summary": "A2A guidance on finding agents through a well-known Agent Card URL (/.well-known/agent-card.json), curated registries, or direct configuration. It notes that the spec does not prescribe a registry API.",
      "tags": [
        "a2a",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261007210746/https://a2a-protocol.org/latest/topics/agent-discovery/"
    },
    {
      "id": "wildcard-agents-json",
      "title": "wild-card-ai/agents-json",
      "publisher": "GitHub (Wildcard)",
      "authors": [],
      "date_published": null,
      "url": "https://github.com/wild-card-ai/agents-json",
      "type": "repo",
      "category": "agent-protocols",
      "summary": "agents.json, an OpenAPI-based contract published at /.well-known/agents.json that describes multi-step API 'flows' for agents, linking the outputs of one operation to the inputs of the next.",
      "tags": [
        "interop",
        "openapi",
        "tools"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20260616065942/https://github.com/wild-card-ai/agents-json"
    },
    {
      "id": "agentskills-io",
      "title": "Agent Skills",
      "publisher": "agentskills.io",
      "authors": [],
      "date_published": null,
      "url": "https://agentskills.io/",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Open format for packaging agent capabilities as SKILL.md files with YAML frontmatter, plus a discovery index schema used by sites at /.well-known/agent-skills/index.json (for example docs.x402.org and mpp.dev).",
      "tags": [
        "interop",
        "tools",
        "agents"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": null
    },
    {
      "id": "agents-md",
      "title": "AGENTS.md",
      "publisher": "agents.md",
      "authors": [],
      "date_published": null,
      "url": "https://agents.md/",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Simple open format for a README-style instruction file aimed at coding agents. mpp.dev publishes one and links it from its API catalog.",
      "tags": [
        "interop",
        "agents"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261019005759/https://agents.md/"
    },
    {
      "id": "rfc-9727-api-catalog",
      "title": "RFC 9727: api-catalog: A Well-Known URI and Link Relation to Help Discovery of APIs",
      "publisher": "IETF",
      "authors": [
        "K. Smith"
      ],
      "date_published": null,
      "url": "https://www.rfc-editor.org/rfc/rfc9727",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "Standards-track RFC (June 2025) defining /.well-known/api-catalog and the api-catalog link relation, which return a linkset of a publisher's APIs with links to their descriptions, docs and status endpoints.",
      "tags": [
        "openapi",
        "interop",
        "standards",
        "http"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20260427180630/https://www.rfc-editor.org/rfc/rfc9727"
    },
    {
      "id": "content-signals",
      "title": "Content Signals",
      "publisher": "contentsignals.org",
      "authors": [],
      "date_published": null,
      "url": "https://contentsignals.org/",
      "type": "spec",
      "category": "agent-protocols",
      "summary": "robots.txt extension (Content-Signal: search=, ai-input=, ai-train=) that declares how crawled content may be used, settable per user-agent. mpp.dev, x402scan and x402.org use it.",
      "tags": [
        "web-agents",
        "interop",
        "regulation"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261014220907/https://contentsignals.org/"
    },
    {
      "id": "w3c-wot-architecture-1-1",
      "title": "Web of Things (WoT) Architecture 1.1",
      "publisher": "W3C",
      "authors": [],
      "date_published": "2023-12-05",
      "url": "https://www.w3.org/TR/wot-architecture11/",
      "type": "spec",
      "category": "iot",
      "summary": "W3C Recommendation defining the abstract architecture of the Web of Things for interoperability across IoT platforms and application domains.",
      "tags": [
        "wot",
        "interop",
        "standards"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261016075929/https://www.w3.org/TR/wot-architecture11/"
    },
    {
      "id": "csa-matter",
      "title": "Matter",
      "publisher": "Connectivity Standards Alliance",
      "authors": [],
      "date_published": null,
      "url": "https://csa-iot.org/all-solutions/matter/",
      "type": "spec",
      "category": "iot",
      "summary": "Connectivity Standards Alliance page for Matter, an industry-unifying standard for reliable, secure, interoperable connectivity between smart home devices, with access to the specification and certification.",
      "tags": [
        "matter",
        "standards",
        "interop"
      ],
      "verified_at": "2026-10-20",
      "last_checked": "2026-10-20",
      "http_status": 200,
      "archive_url": "http://web.archive.org/web/20261014120214/https://csa-iot.org/all-solutions/matter/"
    }
  ]
}