[dependabot]

Bumps @modelcontextprotocol/client from 2.0.0 to 2.4.0.

Release notes

Sourced from @​modelcontextprotocol/client's releases.

@​modelcontextprotocol/client@​2.4.0

Minor Changes

• #3085 a633756 Thanks @​claude! - Add an opt-in for sending scope on refresh-token requests, for authorization servers that reject a refresh without it (Microsoft Entra ID answers AADSTS90009 when the client and the resource are the same app registration, #2718). OAuthClientProvider gains an optional scopeForRefresh(tokens): auth(), and so the transports and withOAuth, sends the string it returns. refreshAuthorization() gains an optional scope. When a scope is sent and the response has none, the sent scope is kept on the returned tokens. Without either option the refresh request and the saved tokens are unchanged.

• #3047 46d9c99 Thanks @​KKonstantinov, @​tobi-oye, @​mattzcarey! - Add the Skills extension (SEP-2640), reachable through new ext/skills subpaths; package root exports are unchanged.

  • @modelcontextprotocol/server/ext/skills: SkillsExtension (attach(server) serves skills/list, skills/get, resources/directory/read and a skill://{+path} resource template), SkillsExtension.load(files) returning a SkillCatalog with entries and reload(), the SkillFiles storage adapter with memorySkillFiles, SkillSource for generated catalogs, skillEntry, and SkillCatalogError. Invalid skills are skipped with a warning (onWarning), or fail under strict. A file whose bytes are valid UTF-8 is served as text, whatever its MIME type; any other file as a base64 blob.
  • @modelcontextprotocol/server/ext/skills/node: loadSkills(folder) and nodeSkillFiles(folder).
  • @modelcontextprotocol/client/ext/skills: SkillsClient with list() (throws on an invalid entry; skipInvalid: true keeps the valid ones and returns the rest in invalid), get(), read(skill, path?) (size, digest and SKILL.md frontmatter verified, SkillVerificationError on a mismatch; a copy from the response cache that fails a check is fetched once more with cacheMode: 'refresh' first) and readDirectory().
  • @modelcontextprotocol/core/ext/skills: schemas, types and constants, including SKILL_LIMITS. The result schemas follow the stable spec, so ttlMs and cacheScope are required.

  SkillsExtension.attach is @experimental: how an extension is wired to a server may change in a minor release. The rest of the Skills API is stable.

  Works on 2025-11-25 and 2026-07-28. On 2026-07-28 only, the server sends the caching fields (ttlMs, cacheScope), and SkillsClient requires them and returns them from list(), get() and readDirectory().

Patch Changes

• #3083 ef38c67 Thanks @​claude! - The bundled Ajv validator is now built with fast-uri 3.1.8 (was 3.1.0). fast-uri 3.1.6 and later reject a $id or $ref whose text before the first colon is not a valid URI scheme (my_tool:output), or whose URN namespace is not valid (urn:my_tool:output): a schema that uses one no longer compiles, and a tool that carries it fails with an invalid-schema error. An underscore without a colon (my_tool_output) and a $ref into #/$defs/... or #/definitions/... are not affected.

• #2762 b022522 Thanks @​pcarleton! - x-mcp-header on a number-typed tool parameter is now rejected, matching the 2026-07-28 spec ("Parameters with type number are not permitted"; clients MUST exclude such tools from tools/list). Previously number was accepted only to satisfy an older conformance fixture that has since been corrected. integer, string and boolean are unaffected.

• Updated dependencies [46d9c99]:

  • @​modelcontextprotocol/core@​2.4.0

@​modelcontextprotocol/client@​2.3.1

Patch Changes

• Updated dependencies []:
  • @​modelcontextprotocol/core@​2.3.1

@​modelcontextprotocol/client@​2.3.0

Minor Changes

• #2901 433eb41 Thanks @​claude! - The HTTP client transports and the OAuth client helpers now follow a redirect only when it stays within the origin of the request (same scheme, host and port, or http to https on the same host with default ports) and keeps the method (a 307 or 308, or any redirect of a GET). Any other redirect is not followed. A transport then fails the request with an error that names the target; the session is kept and later messages still send. OAuth metadata discovery moves on to the next well-known URL, and any other OAuth request fails with an error that gives the status. Same-origin redirects that keep the method keep working on Node, up to five in a row, and no code changes are needed there. If your endpoint redirects to another origin, configure the transport with the URL it redirects to. A requestInit.redirect of 'error' or 'manual' is passed to fetch as it is for the requests a transport sends to the server (POST, GET and DELETE of the Streamable HTTP transport, POST of the SSE transport); for its OAuth requests, and for any other value, requestInit.redirect is not consulted by default. Browsers do not expose the target of a redirect to a page, so there a redirected request fails instead of being followed. Setting redirectPolicy: 'follow' on a transport leaves its redirects to the fetch implementation, as before this change.

Patch Changes

• #2599 5238fba Thanks @​freya0926! - A server can now serve, and a client can now call, tasks/get and tasks/cancel of the Tasks extension (SEP-2663) on a 2026-07-28 connection, when the handler is registered and the request is sent with an explicit schema. Every other method that a protocol revision removed is still refused. If one server factory serves both eras and such a handler is meant for 2025-era clients only, register it only when ctx.era === 'legacy'.

• #2846 63c0fca Thanks @​Sthreal! - Receiving a large message as a single SSE event over Streamable HTTP, such as a tool result of tens of megabytes, is now fast: a 50 MB result that took about 13 seconds arrives in under a second. The client now requires eventsource-parser 3.0.8 or later. SSEClientTransport reads through the eventsource package and gets the same speed-up once that also resolves eventsource-parser 3.0.8 or later.

• #2908 633dd3e Thanks @​claude! - The license field of the package manifests is now Apache-2.0; the LICENSE file shipped in each package carries the full terms, including the MIT text for earlier contributions. No code change.

• #2903 e765b3b Thanks @​claude! - With versionNegotiation in 'auto' or pin mode, a server/discover probe answered with a 2xx that carries no usable reply (a body that is not JSON under application/json, a bare 204, a missing or unaccepted content type) still rejects connect() with EraNegotiationFailed; an empty SSE stream or a 202 surfaces as the probe timeout instead. The message now says the server answered with an unusable reply (...) instead of reading like a network failure. To connect to a 2025 server behind a front that answers the probe this way, pass connect(transport, { prior: { kind: 'legacy' } }) or use mode: 'legacy'.

• #2905 c0cd01a Thanks @​claude! - SSEClientTransport now retries the SSE connection once after onUnauthorized() resolves, as documented. If the retry is also answered with 401, start() rejects with SdkHttpError (ClientHttpAuthentication) instead of calling onUnauthorized() again. A 401 on a later reconnect of a stream that had opened still gets one refresh.

... (truncated)

Commits

• 951fe56 Version Packages (#2959)
• 895007f fix(server): set Allow: POST on stateless legacy 405 responses (#3002)
• 28124db fix(docs): use relative POSIX package entry globs (#3016)
• f7289b3 docs: say that a spec handler's params drop members the spec does not define ...
• a633756 feat(client): add an opt-in for sending scope on token refresh (#3085)
• 10c26b0 chore(node): accept @​hono/node-server 1.x or 2.x (#3084)
• ef38c67 chore(deps): build the bundled ajv with fast-uri 3.1.8 (#3083)
• 5820f79 fix(server): treat an outputSchema root $ref to an object definition as an ob...
• a513cfe docs: close the v1 to v2 quick path with the 2026-07-28 serving decision (#3086)
• c822443 docs(server): mark SkillsExtension.attach as experimental (#3080)
• Additional commits viewable in compare view

[dependabot]

OK, I won't notify you again about this release, but will get in touch when a new version is available. If you'd rather skip all updates until the next major or minor version, let me know by commenting @dependabot ignore this major version or @dependabot ignore this minor version. You can also ignore all major, minor, or patch releases for a dependency by adding an ignore condition with the desired update_types to your config file.

If you change your mind, just re-open this PR and I'll resolve any conflicts on it.