762 pages for error.
Titles and paths first, then pages whose text carries it. Each row opens that page as this site last read it.
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
…ards Track | 2026-02-04 | | [SEP-2164](/seps/2164-resource-not-found-error) | Standardize Resource Not Found Error Code | <Bad…
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
…| Warning conditions | Deprecated feature usage | | error | Error conditions | Operation failures | | critical | Critical conditions | Syste…
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](/specification/2025-03-26/basi…
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…
Prompts
Model Context Protocol · in the page
specification/2025-03-26/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/2025-03-26/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/2025-03-26/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…
Completion
Model Context Protocol · in the page
specification/2025-03-26/server/utilities/completion
…l`: Optional total matches * `hasMore`: Additional results flag ## Error Handling Servers **SHOULD** return standard JSON-RPC errors for common failure cases: * Method not found: `-32601` (Capabi…
Logging
Model Context Protocol · in the page
specification/2025-03-26/server/utilities/logging
…| Warning conditions | Deprecated feature usage | | error | Error conditions | Operation failures | | critical | Critical conditions | Syste…
Pagination
Model Context Protocol · in the page
specification/2025-03-26/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/2025-06-18/basic/authorization
…//datatracker.ietf.org/doc/html/draft-ietf-oauth-v2-1-13#section-5.3) error handling requirements. Invalid or expired tokens **MUST** receive a HTTP 401 response. MCP clients **MUST NOT** send tokens…
Overview
Model Context Protocol · in the page
specification/2025-06-18/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/2025-06-18/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](/specification/2025-06-18/basi…
Transports
Model Context Protocol · in the page
specification/2025-06-18/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/2025-06-18/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/2025-06-18/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/2025-06-18/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/2025-06-18/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/2025-06-18/index
…ional Utilities * Configuration * Progress tracking * Cancellation * Error reporting * Logging ## Security and Trust & Safety The Model Context Protocol enables powerful capabilities through arbitr…
Schema Reference
Model Context Protocol · in the page
specification/2025-06-18/schema
…="schema-reference" /> ## JSON-RPC <div class="type"> ### `JSONRPCError` <div class="tsd-signature"><span class="tsd-signature-keyword">interface</span> <span class="tsd-kind-interface">JSONRPC…
Prompts
Model Context Protocol · in the page
specification/2025-06-18/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/2025-06-18/server/resources
…f.org/doc/html/rfc3986), taking the above guidance in to account. ## 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/2025-06-18/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…
Completion
Model Context Protocol · in the page
specification/2025-06-18/server/utilities/completion
…l`: Optional total matches * `hasMore`: Additional results flag ## Error Handling Servers **SHOULD** return standard JSON-RPC errors for common failure cases: * Method not found: `-32601` (Capabi…
Logging
Model Context Protocol · in the page
specification/2025-06-18/server/utilities/logging
…| Warning conditions | Deprecated feature usage | | error | Error conditions | Operation failures | | critical | Critical conditions | Syste…
Pagination
Model Context Protocol · in the page
specification/2025-06-18/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/2025-11-25/basic/authorization
…ent: 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<br/>(…
Overview
Model Context Protocol · in the page
specification/2025-11-25/basic/index
…ponses are sent in reply to requests, containing either the result or error of the operation. #### Result Responses [Result responses](/specification/2025-11-25/schema#jsonrpcresultresponse) are sen…