936 pages for error.

Skills Model Context Protocol · in the page extensions/skills/overview …ost->>Server: skills/get (URI) Server-->>Host: Skill entry or error end break Lookup failed Note over Host,Server: Stop loading (unknown skill: -32602) end Note over Ho… Tasks Model Context Protocol · in the page extensions/tasks/overview …s the current status and, for terminal states, the final result or error. 4. **Mid-flight input.** If the task moves to `input_required`, the `tasks/get` response includes an `inputRequests` ma… How to Authenticate When Publishing to the Official MCP Registry Model Context Protocol · in the page registry/authentication …will not see it and authentication will fail with a generic signature error. > > If you rotate keys, also remember to remove the previous TXT record from the apex — a stale record left behind will be… How to Automate Publishing with GitHub Actions Model Context Protocol · in the page registry/github-actions …PUBLISHER_VERSION}" curl --fail --location --silent --show-error --output "$archive" "$base_url/$archive" curl --fail --location --silent --show-error --output "$archive.sigstore.… Quickstart: Publish an MCP Server to the MCP Registry Model Context Protocol · in the page registry/quickstart …e":"io.github.my-username/weather" ... }]} ``` ## Troubleshooting | Error Message | Action | | - | - | | "Registry validation failed for package" | Ensure your package includes the required ownershi… Versioning Published MCP Servers Model Context Protocol · in the page registry/versioning …would otherwise be sorted before the semantic version strings. As an error prevention mechanism, the MCP Registry prohibits version strings that appear to refer to ranges of versions. | Example | Ty… SEP-1036: URL Mode Elicitation for secure out-of-band interactions Model Context Protocol · in the page seps/1036-url-mode-elicitation-for-secure-out-of-band-intera …automatically retry requests that received a URL elicitation required error, update the user interface, or otherwise continue an interaction. However, because delivery of the notification is not guara… SEP-1319: Decouple Request Payload from RPC Methods Definition Model Context Protocol · in the page seps/1319-decouple-request-payload-from-rpc-methods-definiti …redundancy and making future updates to the protocol more complex and error-prone. * **Tightly Coupled to JSON-RPC:** Most critically, this tight coupling to JSON-RPC is the primary blocker for defini… SEP-1577: Sampling With Tools Model Context Protocol · in the page seps/1577--sampling-with-tools …### Protocol changes * `sampling/createMessage` * ~~MUST throw an error when `includeContext is “thisServer” | “allServers”` but `clientCapabilities.sampling.context` is missing~~ * MUST throw a… SEP-1686: Tasks Model Context Protocol · in the page seps/1686-tasks …not happen across many tools in a large toolset is time-consuming and error-prone. ***Ideal:*** Support natively polling tool state at the data layer to support pushing a tool to the background and av… SEP-1865: MCP Apps - Interactive User Interfaces for MCP Model Context Protocol · in the page seps/1865-mcp-apps-interactive-user-interfaces-for-mcp …itions, SDKs, etc.). JSON-RPC offers advanced capabilities (timeouts, errors, etc.). **Alternatives considered:** * **Custom message protocol:** Current MCP-UI approach with message types like tool,… SEP-2106: Tools `inputSchema` & `outputSchema` Conform to JSON Schema 2020-12 Model Context Protocol · in the page seps/2106-json-schema-2020-12 …n SDKs for MCP, has implemented extensive workarounds: 1. **Explicit error messages** acknowledge the limitation: ```python theme={null} raise ValueError( f"Output schemas must represen… SEP-2133: Extensions Model Context Protocol · in the page seps/2133-extensions …t to core protocol behavior or reject the request with an appropriate error if the extension is mandatory. Extensions SHOULD document their expected fallback behavior. For example, a server offering U… SEP-2243: HTTP Header Standardization for Streamable HTTP Transport Model Context Protocol · in the page seps/2243-http-standardization …e**: This requirement prevents potential security vulnerabilities and error conditions that could arise when different components in the network rely on different sources of truth. For example, a load… SEP-2260: Require Server requests to be associated with a Client request. Model Context Protocol · in the page seps/2260-Require-Server-requests-to-be-associated-with-Client-requests …outbound request **SHOULD** respond with a `-32602` (Invalid Params) error. ### For Transport Implementers Future transport implementations can rely on the guarantee that: * Sampling/elicitation r… SEP-2322: Multi Round-Trip Requests Model Context Protocol · in the page seps/2322-MRTR …erature: 72°F\nConditions: Partly cloudy" } ], "isError": false } } ``` </details> #### Real-World Example for Ephemeral Workflow This example demonstrates how `requestSt… SEP-2468: Recommend Issuer (iss) Parameter in MCP Auth Responses Model Context Protocol · in the page seps/2468-recommend-issuer-claim-for-auth …ude an issuer (*iss*) parameter in authorization responses, including error responses, as defined in [RFC9207](https://datatracker.ietf.org/doc/html/rfc9207#section-2). Authorization servers that do s… SEP-2549: TTL for List Results Model Context Protocol · in the page seps/2549-TTL-for-list-results …the TTL has not yet expired. Examples include receiving an unexpected error on a tool call indicating that the the method was not found or the parameters were invalid. Clients MAY serve stale respons… SEP-2567: Sessionless MCP via Explicit State Handles Model Context Protocol · in the page seps/2567-sessionless-mcp …ents and recommends — in the same way it might document pagination or error-message conventions — not something it implements. The normative content of this SEP is the removal in (1); (2) follows from… SEP-2575: Make MCP Stateless Model Context Protocol · in the page seps/2575-stateless-mcp …such as an experimental or draft version), it MUST return a JSON-RPC error response. For HTTP, the response status code MUST be `400 Bad Request`. The error MUST conform to the following structure:… SEP-2577: Deprecate Roots, Sampling, and Logging Model Context Protocol · in the page seps/2577-deprecate-roots-sampling-and-logging …— especially across multiple protocol versions — would be complex and error-prone. Deprecation followed by removal is less disruptive: implementations can continue using the features as-is during the… SEP-2640: Skills Extension Model Context Protocol · in the page seps/2640-skills-extension …kills%2Fget) confirms, the server answering for a skill it serves and erroring otherwise. This holds for every scheme, `skill://` included. A host MUST NOT conclude that a resource is a skill merely b… SEP-2663: Tasks Extension Model Context Protocol · in the page seps/2663-tasks-extension …status, in-progress server-to-client requests, and a final result or error. Task creation is server-directed: the client signals support by including the extension in its per-request capabilities, an… SEP-986: Specify Format for Tool Names Model Context Protocol · in the page seps/986-specify-format-for-tool-names …casing, and character sets. This inconsistency can lead to confusion, errors in tool invocation, and difficulties in documentation and automation. Standardizing the allowed characters and length will:… SEP-991: Enable URL-based Client Registration using OAuth Client ID Metadata Documents Model Context Protocol · in the page seps/991-enable-url-based-client-registration-using-oauth-c …MCP responses else Validation Failure Server->>User: Error response<br/>error=invalid_client or invalid_request end Note over Server: Cache metadata for future requests<b… Specification Enhancement Proposals (SEPs) Model Context Protocol · in the page seps/index …EP-2164](https://modelcontextprotocol.io/seps/2164-resource-not-found-error.md) | Standardize Resource Not Found Error Code | Final | Standards Track | 2026-01-28 | | [SEP-2149](https://modelcontextpr… Architecture Model Context Protocol · in the page specification/2024-11-05/architecture/index …arameters expecting a response * **Responses**: Successful results or errors matching specific request IDs * **Notifications**: One-way messages requiring no response Each message type follows the JS… Overview Model Context Protocol · in the page specification/2024-11-05/basic/index …s** are further sub-categorized as either **successful results** or **errors**. Results can follow any JSON object structure, while errors must include an error code and message at minimum. ## Protoc… Lifecycle Model Context Protocol · in the page specification/2024-11-05/basic/lifecycle …utdown is indicated by closing the associated HTTP connection(s). ## Error Handling Implementations **SHOULD** be prepared to handle these error cases: * Protocol version mismatch * Failure to nego… Messages Model Context Protocol · in the page specification/2024-11-05/basic/messages …id: string | number; result?: { [key: string]: unknown; } error?: { code: number; message: string; data?: unknown; } } ``` * Responses **MUST** include the same ID as the re… Transports Model Context Protocol · in the page specification/2024-11-05/basic/transports …ed newlines. * The server **MAY** write UTF-8 strings to its standard error (`stderr`) for logging purposes. Clients **MAY** capture, forward, or ignore this logging. * The server **MUST NOT** write… Cancellation Model Context Protocol · in the page specification/2024-11-05/basic/utilities/cancellation …pplication UIs **SHOULD** indicate when cancellation is requested ## Error Handling Invalid cancellation notifications **SHOULD** be ignored: * Unknown request IDs * Already completed requests * Ma… Ping Model Context Protocol · in the page specification/2024-11-05/basic/utilities/ping …xcessive pinging **SHOULD** be avoided to reduce network overhead ## Error Handling * Timeouts **SHOULD** be treated as connection failures * Multiple failed pings **MAY** trigger connection reset *… Roots Model Context Protocol · in the page specification/2024-11-05/client/roots …e/user/repos/backend", "name": "Backend Repository" } ] ``` ## Error Handling Clients **SHOULD** return standard JSON-RPC errors for common failure cases: * Client does not support roots: `-3… Sampling Model Context Protocol · in the page specification/2024-11-05/client/sampling …he sonnet hint to `gemini-1.5-pro` based on similar capabilities. ## Error Handling Clients **SHOULD** return errors for common failure cases: Example error: ```json theme={null} { "jsonrpc": "2… Specification Model Context Protocol · in the page specification/2024-11-05/index …ional Utilities * Configuration * Progress tracking * Cancellation * Error reporting * Logging ## Security and Trust & Safety The Model Context Protocol enables powerful capabilities through arbitr… Prompts Model Context Protocol · in the page specification/2024-11-05/server/prompts …or other reference materials directly into the conversation flow. ## Error Handling Servers **SHOULD** return standard JSON-RPC errors for common failure cases: * Invalid prompt name: `-32602` (Inv… Resources Model Context Protocol · in the page specification/2024-11-05/server/resources …standard MIME type. ### git:// Git version control integration. ## Error Handling Servers **SHOULD** return standard JSON-RPC errors for common failure cases: * Resource not found: `-32002` * Int… Tools Model Context Protocol · in the page specification/2024-11-05/server/tools …\nTemperature: 72°F\nConditions: Partly cloudy" } ], "isError": false } } ``` ### List Changed Notification When the list of available tools changes, servers that declared the `listC… Logging Model Context Protocol · in the page specification/2024-11-05/server/utilities/logging …anges | | warning | Warning conditions | Deprecated feature usage | | error | Error conditions | Operation failures | | critical | Critical conditions | System component failures | | alert | Action mu… Pagination Model Context Protocol · in the page specification/2024-11-05/server/utilities/pagination …arse or modify cursors * Don't persist cursors across sessions ## Error Handling Invalid cursors **SHOULD** result in an error with code -32602 (Invalid params). Authorization Model Context Protocol · in the page specification/2025-03-26/basic/authorization …//datatracker.ietf.org/doc/html/draft-ietf-oauth-v2-1-12#section-5.3) error handling requirements. Invalid or expired tokens **MUST** receive a HTTP 401 response. ### Security Considerations The fol… Overview Model Context Protocol · in the page specification/2025-03-26/basic/index …es Responses are sent in reply to requests, containing the result or error of the operation. ```typescript theme={null} { jsonrpc: "2.0"; id: string | number; result?: { [key: string]: unk… Lifecycle Model Context Protocol · in the page specification/2025-03-26/basic/lifecycle …d resource exhaustion. When the request has not received a success or error response within the timeout period, the sender **SHOULD** issue a [cancellation notification](https://modelcontextprotocol.i… Transports Model Context Protocol · in the page specification/2025-03-26/basic/transports …ed newlines. * The server **MAY** write UTF-8 strings to its standard error (`stderr`) for logging purposes. Clients **MAY** capture, forward, or ignore this logging. * The server **MUST NOT** write… Cancellation Model Context Protocol · in the page specification/2025-03-26/basic/utilities/cancellation …pplication UIs **SHOULD** indicate when cancellation is requested ## Error Handling Invalid cancellation notifications **SHOULD** be ignored: * Unknown request IDs * Already completed requests * Ma… Ping Model Context Protocol · in the page specification/2025-03-26/basic/utilities/ping …xcessive pinging **SHOULD** be avoided to reduce network overhead ## Error Handling * Timeouts **SHOULD** be treated as connection failures * Multiple failed pings **MAY** trigger connection reset *… Roots Model Context Protocol · in the page specification/2025-03-26/client/roots …e/user/repos/backend", "name": "Backend Repository" } ] ``` ## Error Handling Clients **SHOULD** return standard JSON-RPC errors for common failure cases: * Client does not support roots: `-3… Sampling Model Context Protocol · in the page specification/2025-03-26/client/sampling …he sonnet hint to `gemini-1.5-pro` based on similar capabilities. ## Error Handling Clients **SHOULD** return errors for common failure cases: Example error: ```json theme={null} { "jsonrpc": "2… Specification Model Context Protocol · in the page specification/2025-03-26/index …ional Utilities * Configuration * Progress tracking * Cancellation * Error reporting * Logging ## Security and Trust & Safety The Model Context Protocol enables powerful capabilities through arbitr…