This implements
[SEP-2133](https://modelcontextprotocol.io/community/seps/2133-extensions)
and resolves#777.
## Summary of changes
- Add `Extensions` field to `ServerCapabilities` and
`ClientCapabilities` structs per
[SEP-2133](https://modelcontextprotocol.io/community/seps/2133-extensions)
- Add `AddExtension` helper methods on both types that normalize nil
settings to empty maps.
- [The spec requires an object, not
null](https://modelcontextprotocol.io/community/seps/2133-extensions#negotiation:~:text=an%20empty%20object%20indicates%20no%20settings.)
- Include shallow-copy support via `maps.Clone` in the existing
`clone()` methods
- also include shallow-copy support for `Experimental` field.
- Add comprehensive tests: unit tests for nil-safety, capability
preservation, and over-the-wire round-trip
## What's tested
- [x] `go test ./mcp/...` passes
- [x] Server conformance tests pass (30 scenarios, 40 assertions, 0
failures)
- [x] Client conformance tests match existing baseline (auth scenarios
are known failures)
Implement SEP 986, enforcing restrictions on tool names. Since we're
already at v1 we couldn't turn this into a panic, so use an error log
instead. This is consistent with the typescript SDK. A note is left in
our 'rough edges' doc to panic in v2.
Fixes#621
As discussed at length in
https://github.com/modelcontextprotocol/go-sdk/issues/518, coupling our
schema fields to
jsonschema.Schema limits our user's ability to use a different schema
package, and makes it impossible for our client to talk to some
backends.
This CL relaxes the type of `*jsonschema.Schema` fields to be of type
`any`, which is a breaking change but is unlikely to affect most server
code. (It *is* a nontrivial change for clients).
Fixes https://github.com/modelcontextprotocol/go-sdk/issues/518
Recently, I refactored to fix validation and default application for
structured output. However, I used the wrong byte slice for the
unstructured output. Fix it to use the same bytes as structured output,
with a test.
Fixes#475
Our validation logic was avoiding double-unmarshalling as much as
possible, by parsing before validation and validating the Go type.
This only works if the Go type has the same structure as its JSON
representation, which may not be the case in the presence of types with
custom MarshalJSON or UnmarshalJSON methods (such as time.Time).
But even if the Go type doesn't use any custom marshalling, validation
is broken, because we can't differentiate zero values from missing
values.
Bite the bullet and use double-unmarshalling for both input and output
schemas. Coincidentally, this fixes three bugs:
- We were accepting case-insensitive JSON keys, since we parsed first,
even though they should have been rejected. A number of tests were
wrong.
- Defaults were overriding present-yet-zero values, as noted in an
incorrect test case.
- When "arguments" was missing, validation wasn't performed, no defaults
were applied, and unmarshalling failed even if all properties were
optional.
First unmarshalling to map[string]any allows us to fix all these bugs.
Unfortunately, it means a 3x increase in the number of reflection
operations (we need to unmarshal, apply defaults and validate,
re-marshal with the defaults, and then unmarshal into the Go type).
However, this is not likely to be a significant overhead, and we can
always optimize in the future.
Update github.com/google/jsonschema-go to pick up necessary improvements
supporting this change.
Additionally, fix the error codes for invalid tool parameters, to be
consistent with other SDKs (Invalid Params: -32602).
Fixes#447Fixes#449
Updates #450
toolForErr was ignoring the output schema if the output type was any.
That neglected the case where the user provided their own output schema.
Fixes#371.
remove checks for URI scheme; nothing in the spec requires one
# Background
When adding resource templates, we are currently doing checks for
schemes on absolute uris. It is still common for MCP servers to use
custom uris that would not pass these checks. For example, if the
official GitHub MCP server were to use this sdk, it would show failures
like:
```
"repo://{owner}/{repo}/contents{/path*}": parse "repo://{owner}/{repo}/contents{/path*}": invalid character "{" in host name
"repo://{owner}/{repo}/refs/heads/{branch}/contents{/path*}": parse "repo://{owner}/{repo}/refs/heads/{branch}/contents{/path*}": invalid character "{" in host name
"repo://{owner}/{repo}/sha/{sha}/contents{/path*}": parse "repo://{owner}/{repo}/sha/{sha}/contents{/path*}": invalid character "{" in host name
invalid resource template uri "repo://{owner}/{repo}/refs/pull/{prNumber}/head/contents{/path*}": parse "repo://{owner}/{repo}/refs/pull/{prNumber}/head/contents{/path*}": invalid character "{" in host name
"repo://{owner}/{repo}/refs/tags/{tag}/contents{/path*}": parse "repo://{owner}/{repo}/refs/tags/{tag}/contents{/path*}": invalid character "{" in host name
```
The wikipedia MCP would also show problems with missing schemes.
```
"/search/{query}": <nil>
"/article/{title}": <nil>
"/summary/{title}": <nil>
"/summary/{title}/query/{query}/length/{max_length}": <nil>
"/summary/{title}/section/{section_title}/length/{max_length}": <nil>
"/sections/{title}": <nil>
"/links/{title}": <nil>
"/facts/{title}/topic/{topic_within_article}/count/{count}": <nil>
"/coordinates/{title}": <nil>
```
The spec makes it clear that input schemas must have type "object".
Enforce that.
Allow "any" as an input argument type by special-casing it.
Fixes#283.
Replace all occurrences of ServerRequest[*CallToolParams] and other
concrete instantiations with CallToolRequest and the like.
Make the XXXRequest types aliases, to preserve the convenience of
generics for the internal machinery (see shared.go, for example.)
I will expand the aliases in a followup PR.
Export ServerCapabilities and related subtypes and update protocol,
server, and tests to use exported types. Add InitializeResult method on
ClientSession for accessing the initialize result from sessions.
Fixes: https://github.com/modelcontextprotocol/go-sdk/issues/166
Co-authored-by: Shashank Pachava <spachava753@gmail.com>
Handlers and client/server methods take a single request argument
combining the session and params. This slightly simplifies the signature
for handlers, since there is no longer an often-ignored session
argument.
But more importantly, it opens the door to adding more information in
requests, such as auth info and HTTP request headers.
For #243.
## Background
Since the Server has a map of ServersSessions->subscriptions, and takes
care of routing ResourceUpdate messages to ServerSessions, I think the
decision was made to leave *ServerSession out of the
SubscribeHandler/UnsubscribeHandler signatures. However, resource
subscriptions are not specific to the a particular client and this
information is kept private in the Session today.
## Proposal
Align the Subscribe/Unsubscribe handlers with the other two handlers
that are client specific (ProgressNotificationHandler, and
RootListChangeHanlder), and include *ServerSession in the signature.
It comes in practice because because a gateway server that needs to
forward subscriptions still needs this information. The routing logic in
Server is convenient and means that most servers won't need to know
which ServerSessions are subscribed. But I think there are still use
cases where the user will need to know.
This CL adds an option for servers to advertise support for features
that have not been added yet. This includes Prompts, Tools, and
Resources as these could be dynamically added after initialization.
Fixes: #135.
If tools are added to a Server when Run is called, it will send
toolCapabilities to the client. Otherwise it won't. Ditto for prompts
and resources.
For #56.
This CL simplifies the paginateList function in server.go to use a
generic helper for tools, resources, and prompts.
Change-Id: Ide0d2a90d715374280067e094d8870882e6bddfa
Reviewed-on: https://go-review.googlesource.com/c/tools/+/678055
Auto-Submit: Sam Thanawalla <samthanawalla@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This CL streamlines the client side pagination logic by adding a generic
helper that handles pagination. This also simplifies the existing tools
iterator method.
Change-Id: If4304deda1ccd22d0c4580d76deaefc64e5dfeb9
Reviewed-on: https://go-review.googlesource.com/c/tools/+/676975
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Sam Thanawalla <samthanawalla@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
