{
  "title": "What Is an MCP Server? — Normalized Claim Register",
  "schemaVersion": "1.0",
  "researchFreeze": "2026-08-25",
  "protocolRevision": "2026-07-28",
  "idNote": "packageSourceIds preserve the research package namespace; sourceIds resolve into the site-wide evidence library.",
  "count": 81,
  "records": [
    {
      "claimId": "C001",
      "claim": "The current official MCP protocol revision is 2026-07-28 as of 2026-08-25.",
      "dateRange": "Current as of 2026-08-25",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S001",
        "S017",
        "S018"
      ],
      "sourceIds": [
        "S054",
        "S055",
        "S058"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Recheck immediately before publication."
    },
    {
      "claimId": "C002",
      "claim": "MCP is an open protocol for connecting AI applications with external capabilities and context.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S001"
      ],
      "sourceIds": [
        "S054"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Use 'open protocol'; do not imply formal standards-body status."
    },
    {
      "claimId": "C003",
      "claim": "An MCP server is a program or network service implementing the server side of MCP.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S002",
        "S003"
      ],
      "sourceIds": [
        "S121",
        "S122"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Conceptual synthesis of official server role."
    },
    {
      "claimId": "C004",
      "claim": "An MCP host is the user-facing container and coordinator that manages clients, permissions, model integration and context.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S002"
      ],
      "sourceIds": [
        "S121"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Host is not server."
    },
    {
      "claimId": "C005",
      "claim": "A host may create multiple MCP clients, with each client communicating with exactly one server.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S002"
      ],
      "sourceIds": [
        "S121"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "One-to-one client/server relation within a host."
    },
    {
      "claimId": "C006",
      "claim": "MCP servers can be local processes or remote services.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S002",
        "S003"
      ],
      "sourceIds": [
        "S121",
        "S122"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Do not equate MCP with only local or only remote."
    },
    {
      "claimId": "C007",
      "claim": "MCP protocol messages use JSON-RPC 2.0.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S001",
        "S011",
        "S033"
      ],
      "sourceIds": [
        "S054",
        "S130",
        "S001"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "JSON-RPC is the envelope, not the whole protocol."
    },
    {
      "claimId": "C008",
      "claim": "Current MCP has a stateless protocol core in which each request is self-contained.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S011",
        "S017",
        "S018"
      ],
      "sourceIds": [
        "S130",
        "S055",
        "S058"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Stateless protocol does not mean stateless application."
    },
    {
      "claimId": "C009",
      "claim": "The initialize/initialized handshake was removed in 2026-07-28.",
      "dateRange": "2026-07-28",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S017",
        "S018"
      ],
      "sourceIds": [
        "S055",
        "S058"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Older revisions used it."
    },
    {
      "claimId": "C010",
      "claim": "Protocol-level sessions and Mcp-Session-Id were removed in 2026-07-28.",
      "dateRange": "2026-07-28",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S017",
        "S018"
      ],
      "sourceIds": [
        "S055",
        "S058"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Application state can still use explicit handles."
    },
    {
      "claimId": "C011",
      "claim": "Servers must implement server/discover in 2026-07-28.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S008",
        "S017"
      ],
      "sourceIds": [
        "S127",
        "S055"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Server requirement."
    },
    {
      "claimId": "C012",
      "claim": "Clients may call server/discover before another request but are not required to do so.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S008",
        "S017",
        "S018"
      ],
      "sourceIds": [
        "S127",
        "S055",
        "S058"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Do not call this a mandatory handshake."
    },
    {
      "claimId": "C013",
      "claim": "MCP tools are discovered with tools/list and invoked with tools/call.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S004"
      ],
      "sourceIds": [
        "S123"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Core tool methods."
    },
    {
      "claimId": "C014",
      "claim": "Tool definitions include names, descriptions and input schemas, and may include output schemas and annotations.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S004"
      ],
      "sourceIds": [
        "S123"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Current schema uses JSON Schema."
    },
    {
      "claimId": "C015",
      "claim": "Tool results can include text, images, audio, resource links, embedded resources and structured content.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S004"
      ],
      "sourceIds": [
        "S123"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Host support may vary."
    },
    {
      "claimId": "C016",
      "claim": "Tool annotations are hints and are not security guarantees.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S001",
        "S004"
      ],
      "sourceIds": [
        "S054",
        "S123"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Treat untrusted server metadata as untrusted."
    },
    {
      "claimId": "C017",
      "claim": "MCP resources are URI-identified data that clients can list and read.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S005"
      ],
      "sourceIds": [
        "S124"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "A tool result is not automatically a resource."
    },
    {
      "claimId": "C018",
      "claim": "MCP prompts are server-provided templates or structured messages surfaced for user invocation.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S006"
      ],
      "sourceIds": [
        "S125"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Not the same as a system prompt."
    },
    {
      "claimId": "C019",
      "claim": "Form-mode elicitation must not request passwords, API keys, access tokens or payment credentials.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S007"
      ],
      "sourceIds": [
        "S126"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Sensitive interaction should use URL mode."
    },
    {
      "claimId": "C020",
      "claim": "Current MCP represents additional server-required input through Multi Round-Trip Requests.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S010",
        "S017"
      ],
      "sourceIds": [
        "S129",
        "S055"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Replaced prior server-initiated requests."
    },
    {
      "claimId": "C021",
      "claim": "MCP Apps is an optional extension for interactive HTML interfaces rendered by compatible hosts.",
      "dateRange": "Current",
      "specVersion": "Extension",
      "packageSourceIds": [
        "S020",
        "S021"
      ],
      "sourceIds": [
        "S136",
        "S059"
      ],
      "confidence": "VERIFIED",
      "durability": "PERIODICALLY REVIEW",
      "notes": "Host support is volatile."
    },
    {
      "claimId": "C022",
      "claim": "MCP Apps launched as the first official MCP extension on 2026-01-26.",
      "dateRange": "2026-01-26",
      "specVersion": "Extension",
      "packageSourceIds": [
        "S021"
      ],
      "sourceIds": [
        "S059"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Historical launch claim."
    },
    {
      "claimId": "C023",
      "claim": "MCP Tasks is an optional extension for durable asynchronous work.",
      "dateRange": "Current",
      "specVersion": "io.modelcontextprotocol/tasks",
      "packageSourceIds": [
        "S022",
        "S023"
      ],
      "sourceIds": [
        "S137",
        "S060"
      ],
      "confidence": "VERIFIED",
      "durability": "PERIODICALLY REVIEW",
      "notes": "Not every long tool call is a Task."
    },
    {
      "claimId": "C024",
      "claim": "Tasks can provide task IDs, polling, input-required states, cooperative cancellation and terminal results.",
      "dateRange": "Current",
      "specVersion": "io.modelcontextprotocol/tasks",
      "packageSourceIds": [
        "S022"
      ],
      "sourceIds": [
        "S137"
      ],
      "confidence": "VERIFIED",
      "durability": "PERIODICALLY REVIEW",
      "notes": "Extension semantics."
    },
    {
      "claimId": "C025",
      "claim": "In stdio, the client launches or reaches a process and exchanges newline-delimited JSON-RPC over standard streams.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S013"
      ],
      "sourceIds": [
        "S132"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Canonical local binding."
    },
    {
      "claimId": "C026",
      "claim": "A stdio server must not write non-protocol output to stdout and may log to stderr.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S013"
      ],
      "sourceIds": [
        "S132"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Operationally important."
    },
    {
      "claimId": "C027",
      "claim": "Current Streamable HTTP exposes one POST endpoint and sends each JSON-RPC message in its own POST.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S012"
      ],
      "sourceIds": [
        "S131"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Remote transport."
    },
    {
      "claimId": "C028",
      "claim": "A current Streamable HTTP request may receive a JSON response or a request-scoped SSE stream.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S012"
      ],
      "sourceIds": [
        "S131"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "SSE remains a streaming format."
    },
    {
      "claimId": "C029",
      "claim": "The original HTTP+SSE transport is deprecated and was replaced by Streamable HTTP.",
      "dateRange": "2025-03-26 onward",
      "specVersion": "2025-03-26/2026-07-28",
      "packageSourceIds": [
        "S012",
        "S016"
      ],
      "sourceIds": [
        "S131",
        "S135"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Do not say Streamable HTTP was in the launch spec."
    },
    {
      "claimId": "C030",
      "claim": "Current Streamable HTTP removed the earlier GET stream and protocol sessions.",
      "dateRange": "2026-07-28",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S012",
        "S017"
      ],
      "sourceIds": [
        "S131",
        "S055"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Breaking change."
    },
    {
      "claimId": "C031",
      "claim": "Streamable HTTP servers must validate Origin and should bind locally only to localhost when run locally.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S012"
      ],
      "sourceIds": [
        "S131"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "DNS-rebinding mitigation."
    },
    {
      "claimId": "C032",
      "claim": "MCP's HTTP authorization framework is based on OAuth-related standards and treats the protected MCP server as a resource server.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S014"
      ],
      "sourceIds": [
        "S133"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "OAuth is authorization, not complete security."
    },
    {
      "claimId": "C033",
      "claim": "Stdio implementations should not use the HTTP authorization specification and normally retrieve credentials from the environment.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S011",
        "S014"
      ],
      "sourceIds": [
        "S130",
        "S133"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Custom strategies remain possible."
    },
    {
      "claimId": "C034",
      "claim": "Dynamic Client Registration is deprecated in 2026-07-28 in favor of Client ID Metadata Documents.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S014",
        "S016",
        "S017"
      ],
      "sourceIds": [
        "S133",
        "S135",
        "S055"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Migration status."
    },
    {
      "claimId": "C035",
      "claim": "The official MCP Registry remains in preview as of 2026-08-25.",
      "dateRange": "Current as of 2026-08-25",
      "specVersion": "Preview",
      "packageSourceIds": [
        "S026",
        "S027"
      ],
      "sourceIds": [
        "S067",
        "S066"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Recheck before publication."
    },
    {
      "claimId": "C036",
      "claim": "The official Registry hosts metadata and namespace verification while package registries host code or binaries.",
      "dateRange": "Current",
      "specVersion": "Preview",
      "packageSourceIds": [
        "S026"
      ],
      "sourceIds": [
        "S067"
      ],
      "confidence": "VERIFIED",
      "durability": "PERIODICALLY REVIEW",
      "notes": "Protocol distribution is separate from packaging."
    },
    {
      "claimId": "C037",
      "claim": "Registry inclusion is not a security certification; code scanning is delegated substantially to package registries and downstream aggregators.",
      "dateRange": "Current",
      "specVersion": "Preview",
      "packageSourceIds": [
        "S026"
      ],
      "sourceIds": [
        "S067"
      ],
      "confidence": "VERIFIED",
      "durability": "PERIODICALLY REVIEW",
      "notes": "Important trust caveat."
    },
    {
      "claimId": "C038",
      "claim": "Current official SDK Tier 1 languages are TypeScript, Python, C# and Go.",
      "dateRange": "Current as of 2026-08-25",
      "specVersion": "Current",
      "packageSourceIds": [
        "S024",
        "S025"
      ],
      "sourceIds": [
        "S138",
        "S073"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Recheck tiers."
    },
    {
      "claimId": "C039",
      "claim": "Current official SDK Tier 2 languages are Java, Rust and Ruby.",
      "dateRange": "Current as of 2026-08-25",
      "specVersion": "Current",
      "packageSourceIds": [
        "S024",
        "S025"
      ],
      "sourceIds": [
        "S138",
        "S073"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Recheck tiers."
    },
    {
      "claimId": "C040",
      "claim": "Current official SDK Tier 3 languages are Swift, PHP and Kotlin.",
      "dateRange": "Current as of 2026-08-25",
      "specVersion": "Current",
      "packageSourceIds": [
        "S024",
        "S025"
      ],
      "sourceIds": [
        "S138",
        "S073"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Recheck tiers."
    },
    {
      "claimId": "C041",
      "claim": "The official repository credits David Soria Parra and Justin Spahr-Summers as MCP's creators.",
      "dateRange": "Current repository credit",
      "specVersion": "Origin",
      "packageSourceIds": [
        "S029"
      ],
      "sourceIds": [
        "S023"
      ],
      "confidence": "VERIFIED",
      "durability": "PERIODICALLY REVIEW",
      "notes": "Creator credit is not every-contributor credit."
    },
    {
      "claimId": "C042",
      "claim": "Anthropic publicly announced MCP on 2024-11-25.",
      "dateRange": "2024-11-25",
      "specVersion": "Launch",
      "packageSourceIds": [
        "S028"
      ],
      "sourceIds": [
        "S021"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Public announcement date."
    },
    {
      "claimId": "C043",
      "claim": "The first named MCP specification revision is dated 2024-11-05.",
      "dateRange": "2024-11-05",
      "specVersion": "2024-11-05",
      "packageSourceIds": [
        "S030"
      ],
      "sourceIds": [
        "S024"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Not the announcement date."
    },
    {
      "claimId": "C044",
      "claim": "The earliest public specification repository evidence located in this research is the 2024-09-24 initial import.",
      "dateRange": "2024-09-24",
      "specVersion": "Early draft",
      "packageSourceIds": [
        "S031"
      ],
      "sourceIds": [
        "S013"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Does not prove internal development began that day."
    },
    {
      "claimId": "C045",
      "claim": "The earliest verified public reference-server repository commit is dated 2024-11-19.",
      "dateRange": "2024-11-19",
      "specVersion": "Early servers",
      "packageSourceIds": [
        "S032"
      ],
      "sourceIds": [
        "S019"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Contains multiple servers."
    },
    {
      "claimId": "C046",
      "claim": "No definitive first internal MCP server can be established from the public record reviewed.",
      "dateRange": "Pre-launch",
      "specVersion": "Origin",
      "packageSourceIds": [
        "S032"
      ],
      "sourceIds": [
        "S019"
      ],
      "confidence": "INFERRED",
      "durability": "DURABLE",
      "notes": "Preserve uncertainty."
    },
    {
      "claimId": "C047",
      "claim": "MCP was consciously inspired by the Language Server Protocol.",
      "dateRange": "Origin/current",
      "specVersion": "All",
      "packageSourceIds": [
        "S001",
        "S031",
        "S034"
      ],
      "sourceIds": [
        "S054",
        "S013",
        "S139"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Not merely a secondary analogy."
    },
    {
      "claimId": "C048",
      "claim": "The LSP comparison explains a shared client/server protocol reducing pairwise integration work.",
      "dateRange": "Conceptual",
      "specVersion": "All",
      "packageSourceIds": [
        "S034"
      ],
      "sourceIds": [
        "S139"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "DURABLE",
      "notes": "Do not claim cost is eliminated."
    },
    {
      "claimId": "C049",
      "claim": "Function calling predates MCP's public release.",
      "dateRange": "2023 vs 2024",
      "specVersion": "Historical",
      "packageSourceIds": [
        "S035",
        "S042"
      ],
      "sourceIds": [
        "S010",
        "S143"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "MCP did not invent function calling."
    },
    {
      "claimId": "C050",
      "claim": "MCP and function calling operate at different layers and commonly complement one another.",
      "dateRange": "Conceptual/current",
      "specVersion": "All",
      "packageSourceIds": [
        "S004",
        "S035"
      ],
      "sourceIds": [
        "S123",
        "S010"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "DURABLE",
      "notes": "Host mapping is implementation-specific."
    },
    {
      "claimId": "C051",
      "claim": "MCP does not replace REST, GraphQL, databases, CLIs or other underlying interfaces.",
      "dateRange": "Conceptual/current",
      "specVersion": "All",
      "packageSourceIds": [
        "S002",
        "S003",
        "S004",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S122",
        "S123",
        "S124"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "DURABLE",
      "notes": "Architectural inference from server role."
    },
    {
      "claimId": "C052",
      "claim": "A plugin or connector is not automatically an MCP server.",
      "dateRange": "Conceptual/current",
      "specVersion": "All",
      "packageSourceIds": [
        "S036",
        "S044",
        "S045"
      ],
      "sourceIds": [
        "S009",
        "S145",
        "S146"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "DURABLE",
      "notes": "Product terms vary."
    },
    {
      "claimId": "C053",
      "claim": "An MCP server is not inherently an AI agent.",
      "dateRange": "Conceptual/current",
      "specVersion": "All",
      "packageSourceIds": [
        "S002",
        "S003",
        "S022"
      ],
      "sourceIds": [
        "S121",
        "S122",
        "S137"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "DURABLE",
      "notes": "Agent may use or be wrapped by a server."
    },
    {
      "claimId": "C054",
      "claim": "MCP can be used programmatically without model reasoning.",
      "dateRange": "Conceptual/current",
      "specVersion": "All",
      "packageSourceIds": [
        "S003",
        "S004",
        "S024"
      ],
      "sourceIds": [
        "S122",
        "S123",
        "S138"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "DURABLE",
      "notes": "Protocol does not require an LLM for every call."
    },
    {
      "claimId": "C055",
      "claim": "MCP compliance is not a security guarantee.",
      "dateRange": "Current",
      "specVersion": "All",
      "packageSourceIds": [
        "S001",
        "S015",
        "S049",
        "S050",
        "S052"
      ],
      "sourceIds": [
        "S054",
        "S134",
        "S108",
        "S109",
        "S111"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "DURABLE",
      "notes": "Security spans multiple layers."
    },
    {
      "claimId": "C056",
      "claim": "MCP does not automatically solve prompt injection.",
      "dateRange": "Current",
      "specVersion": "All",
      "packageSourceIds": [
        "S001",
        "S049"
      ],
      "sourceIds": [
        "S054",
        "S108"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Transporting context can carry malicious instructions."
    },
    {
      "claimId": "C057",
      "claim": "Tool-poisoning research was publicly disclosed by Invariant Labs on 2025-04-01.",
      "dateRange": "2025-04-01",
      "specVersion": "2025-era",
      "packageSourceIds": [
        "S049"
      ],
      "sourceIds": [
        "S108"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Original research source."
    },
    {
      "claimId": "C058",
      "claim": "A local MCP server is ordinary executable code and may act outside its advertised tool list subject to OS permissions.",
      "dateRange": "Current",
      "specVersion": "All",
      "packageSourceIds": [
        "S013",
        "S039"
      ],
      "sourceIds": [
        "S132",
        "S141"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "DURABLE",
      "notes": "Core package-trust warning."
    },
    {
      "claimId": "C059",
      "claim": "The MCP Inspector had a public missing-authentication vulnerability patched in 0.14.1.",
      "dateRange": "2025",
      "specVersion": "Implementation",
      "packageSourceIds": [
        "S050"
      ],
      "sourceIds": [
        "S109"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Implementation vulnerability, not abstract protocol flaw."
    },
    {
      "claimId": "C060",
      "claim": "The MCP Inspector had a public XSS vulnerability patched in 0.16.6.",
      "dateRange": "2025",
      "specVersion": "Implementation",
      "packageSourceIds": [
        "S051"
      ],
      "sourceIds": [
        "S110"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Implementation vulnerability."
    },
    {
      "claimId": "C061",
      "claim": "Official SDK HTTP defaults have had DNS-rebinding vulnerabilities.",
      "dateRange": "2025",
      "specVersion": "Implementation",
      "packageSourceIds": [
        "S052",
        "S053"
      ],
      "sourceIds": [
        "S111",
        "S112"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Representative, not exhaustive."
    },
    {
      "claimId": "C062",
      "claim": "The TypeScript SDK had a public cross-client data isolation vulnerability patched in 1.26.0.",
      "dateRange": "2026",
      "specVersion": "Implementation",
      "packageSourceIds": [
        "S054"
      ],
      "sourceIds": [
        "S147"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Multi-client isolation defect."
    },
    {
      "claimId": "C063",
      "claim": "ChatGPT currently connects to remote MCP servers rather than directly to local MCP servers.",
      "dateRange": "Current as of 2026-08-25",
      "specVersion": "Product",
      "packageSourceIds": [
        "S037"
      ],
      "sourceIds": [
        "S140"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Secure tunnel may bridge private/local deployments."
    },
    {
      "claimId": "C064",
      "claim": "Current VS Code supports local and remote MCP servers and offers trust, policy and local sandboxing controls.",
      "dateRange": "Current as of 2026-08-25",
      "specVersion": "Product",
      "packageSourceIds": [
        "S039"
      ],
      "sourceIds": [
        "S141"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Sandbox availability can vary by OS."
    },
    {
      "claimId": "C065",
      "claim": "Gemini CLI currently documents stdio, legacy SSE and Streamable HTTP MCP configurations.",
      "dateRange": "Current as of 2026-08-25",
      "specVersion": "Product",
      "packageSourceIds": [
        "S043"
      ],
      "sourceIds": [
        "S144"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Legacy SSE support is compatibility, not current spec architecture."
    },
    {
      "claimId": "C066",
      "claim": "Claude currently supports custom remote MCP connectors, with connections originating from Anthropic's cloud.",
      "dateRange": "Current as of 2026-08-25",
      "specVersion": "Product",
      "packageSourceIds": [
        "S044",
        "S045"
      ],
      "sourceIds": [
        "S145",
        "S146"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Plan and networking requirements vary."
    },
    {
      "claimId": "C067",
      "claim": "Official support from multiple vendors is stronger adoption evidence than the existence of community wrappers for their APIs.",
      "dateRange": "Analytical",
      "specVersion": "All",
      "packageSourceIds": [
        "S037",
        "S039",
        "S043",
        "S044",
        "S046",
        "S047",
        "S048"
      ],
      "sourceIds": [
        "S140",
        "S141",
        "S144",
        "S145",
        "S093",
        "S092",
        "S091"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "PERIODICALLY REVIEW",
      "notes": "Adoption classification principle."
    },
    {
      "claimId": "C068",
      "claim": "Protocol interoperability does not guarantee identical user experience or model behavior across hosts.",
      "dateRange": "Current",
      "specVersion": "All",
      "packageSourceIds": [
        "S002",
        "S003",
        "S037",
        "S039",
        "S043"
      ],
      "sourceIds": [
        "S121",
        "S122",
        "S140",
        "S141",
        "S144"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "DURABLE",
      "notes": "Host responsibilities differ."
    },
    {
      "claimId": "C069",
      "claim": "Current complete list/read/discovery results include standardized cache information.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S009",
        "S017"
      ],
      "sourceIds": [
        "S128",
        "S055"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Input-required results are not cacheable."
    },
    {
      "claimId": "C070",
      "claim": "Roots, sampling and logging are deprecated in the 2026-07-28 specification but remain present during the migration window.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S016",
        "S017"
      ],
      "sourceIds": [
        "S135",
        "S055"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "New implementations should not adopt them."
    },
    {
      "claimId": "C071",
      "claim": "HTTP+SSE is deprecated under the formal feature-lifecycle policy.",
      "dateRange": "Current",
      "specVersion": "2026-07-28",
      "packageSourceIds": [
        "S016"
      ],
      "sourceIds": [
        "S135"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Migration path is Streamable HTTP."
    },
    {
      "claimId": "C072",
      "claim": "Open-source protocol components do not require every MCP-compatible host or server to be open source.",
      "dateRange": "Conceptual/current",
      "specVersion": "All",
      "packageSourceIds": [
        "S024",
        "S029",
        "S055"
      ],
      "sourceIds": [
        "S138",
        "S023",
        "S069"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "DURABLE",
      "notes": "Protocol compatibility and licensing are separate."
    },
    {
      "claimId": "C073",
      "claim": "MCP is not an IETF, W3C or ISO standard.",
      "dateRange": "Current",
      "specVersion": "Governance",
      "packageSourceIds": [
        "S055",
        "S056",
        "S057"
      ],
      "sourceIds": [
        "S069",
        "S071",
        "S070"
      ],
      "confidence": "STRONGLY_SUPPORTED",
      "durability": "PERIODICALLY REVIEW",
      "notes": "Describe as open protocol/specification, not formal internet standard."
    },
    {
      "claimId": "C074",
      "claim": "MCP is not controlled only by Anthropic; it has public maintainer governance and a SEP process.",
      "dateRange": "Current",
      "specVersion": "Governance",
      "packageSourceIds": [
        "S055",
        "S056"
      ],
      "sourceIds": [
        "S069",
        "S071"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Anthropic originated and remains influential."
    },
    {
      "claimId": "C075",
      "claim": "MCP's current institutional home is the Agentic AI Foundation under the Linux Foundation.",
      "dateRange": "Since 2025-12-09",
      "specVersion": "Governance",
      "packageSourceIds": [
        "S057"
      ],
      "sourceIds": [
        "S070"
      ],
      "confidence": "VERIFIED",
      "durability": "PERIODICALLY REVIEW",
      "notes": "Technical governance retained by MCP project."
    },
    {
      "claimId": "C076",
      "claim": "Roadmap items are priorities or proposals, not shipped protocol features.",
      "dateRange": "Current",
      "specVersion": "Roadmap",
      "packageSourceIds": [
        "S058"
      ],
      "sourceIds": [
        "S064"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Keep future work out of current semantics."
    },
    {
      "claimId": "C077",
      "claim": "The article intentionally avoids server-count, download and GitHub-star statistics as proof of adoption.",
      "dateRange": "Methodology",
      "specVersion": "N/A",
      "packageSourceIds": [
        "S059"
      ],
      "sourceIds": [
        "S148"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Methodological control, not external fact."
    },
    {
      "claimId": "C078",
      "claim": "Current product support, SDK tiers, registry status and governance must be live-checked at publication.",
      "dateRange": "Methodology",
      "specVersion": "Current",
      "packageSourceIds": [
        "S024",
        "S025",
        "S026",
        "S037",
        "S039",
        "S043",
        "S044",
        "S056"
      ],
      "sourceIds": [
        "S138",
        "S073",
        "S067",
        "S140",
        "S141",
        "S144",
        "S145",
        "S071"
      ],
      "confidence": "VERIFIED",
      "durability": "LIVE-CHECK REQUIRED",
      "notes": "Update policy."
    },
    {
      "claimId": "C079",
      "claim": "JSON-RPC batching entered MCP in 2025-03-26 and was removed in 2025-06-18.",
      "dateRange": "2025-03-26 to 2025-06-18",
      "specVersion": "2025-03-26/2025-06-18",
      "packageSourceIds": [
        "S067",
        "S068"
      ],
      "sourceIds": [
        "S036",
        "S043"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "A released design reversal; do not describe batching as current MCP behavior."
    },
    {
      "claimId": "C080",
      "claim": "The original 2025-03-26 form of Streamable HTTP retained initialization and optional protocol sessions using Mcp-Session-Id.",
      "dateRange": "2025-03-26 through 2025-11-25",
      "specVersion": "2025-03-26",
      "packageSourceIds": [
        "S069",
        "S070"
      ],
      "sourceIds": [
        "S038",
        "S156"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Do not project 2026 stateless semantics backward."
    },
    {
      "claimId": "C081",
      "claim": "Experimental Tasks entered the core specification in 2025-11-25 before becoming an official extension in 2026-07-28.",
      "dateRange": "2025-11-25 to 2026-07-28",
      "specVersion": "2025-11-25/2026-07-28",
      "packageSourceIds": [
        "S071",
        "S022",
        "S023"
      ],
      "sourceIds": [
        "S049",
        "S137",
        "S060"
      ],
      "confidence": "VERIFIED",
      "durability": "DURABLE",
      "notes": "Ordinary tool calls are not Tasks."
    }
  ]
}