Commit graph

408 commits

Author SHA1 Message Date
Rob Findley
2c40bdc4d7 mcp: systematically improve streamable client errors
The streamable client connection can break for a variety of reasons,
asynchronously to the client's request. Decorate these failures with
additional context to clarify why they occurred.

Add a test for the failure message of #393.

Fixes #393
2025-09-04 14:09:37 -04:00
Rob Findley
a4313f92bf mcp: refactor the streamable client test to be more flexible
Use a fake streamable server to facilitate testing client behavior.
For this commit, just update the existing test (moved to a new file for
isolation). Subsequent CLs will add more tests.

Improve one client error message that occurred while debuging tests.

For #393
2025-09-04 14:09:37 -04:00
Jonathan Amsterdam
30261728f7
mcp: validate user-provided output schemas (#408)
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.
2025-09-04 14:04:27 -04:00
Rob Findley
07b9cee8cc mcp: flush headers immediately for the hanging GET
Flush headers immediately for the persistent hanging GET of the
streamable transport; otherwise, clients may time out.

Fixes #410
2025-09-04 12:40:07 -04:00
Jonathan Amsterdam
203792dfdc
mcp: improve docs around tool handlers (#414) 2025-09-04 11:13:17 -04:00
ln-12
4257528dde
mcp: set default logging level to info (#411)
During initialization, the default logging level is set to info allowing
servers to emit logs immediately without waiting for a client to set a
log level.
The updated example shows how to send a notification in the context of
the request.

Fixes #387
2025-09-04 11:10:39 -04:00
Rob Findley
a1eb4849b7 mcp: correctly disallow GET requests on stateless servers
The condition sessionID == "" was not quite right for disallowing GET
requests. Since we decided to differentiate "stateless" vs "sessionless"
servers, we need to disallow GET requests for both.

For #393
2025-09-03 19:25:25 -04:00
Jonathan Amsterdam
92e19c1be8
examples/server/auth-middleware: remove custom middleware (#405)
The additional middleware added the TokenInfo the context.
RequireBearerToken already does that.
2025-09-03 17:27:38 -04:00
Jonathan Amsterdam
8314ec099b
mcp: validate tool output (#352)
Validate the handler's returned output against the output schema of a tool.

Fixes #301.
2025-09-03 16:25:48 -04:00
Jonathan Amsterdam
d0c5943f25
add HTTP Request to TokenVerifier (#404)
The request might be needed to verify the token.

Fixes #403.
2025-09-03 16:23:42 -04:00
Jonathan Amsterdam
29c1650e2a
internal/oauthex: OAuth extensions (#125)
Add a package for the extensions to OAuth 2.0 required by MCP.

This first PR adds Protected Resource Metadata.
2025-09-03 14:20:53 -04:00
Shusaku Yasoda
1250a31b51
auth: add OAuth error handling in TokenVerifier and tests (#399)
Add ErrOAuth error type and handling to match TypeScript SDK behavior.
OAuth protocol errors now return HTTP 400 instead of 500, providing
better error classification for authentication issues.

Changes

- Add ErrOAuth variable for OAuth-specific protocol errors
- Update verify function to return 400 for OAuth errors
- Add test case for OAuth error handling


Fixes compatibility with TypeScript SDK error handling patterns.
2025-09-03 13:05:07 -04:00
ccpro
1c20560beb
mcp: export jsonResponse field
Exporting StreamableHTTPOptions.JSONResponse is helpful for some users behind proxies that don't work well with text/event-stream.

For #211

Co-authored-by: ccpro10 <co1797249167@gmail.com>
2025-09-03 11:35:19 -04:00
Robert Findley
c76d991f05
examples/server/distributed: address comment in #380
I failed to push my branch before merging #380. Address one minor
comment from that PR.
2025-09-03 11:34:39 -04:00
Jonathan Amsterdam
0bb1a42b53
examples/server/middleware: log tool result (#400)
Log the result of a tool call in the middleware.

This example now fully demonstrates that receiving middleware can
effectively wrap a ToolHandler. That means that one reason for ToolFor
is moot: you don't need to get your hands on the returned ToolHandler in
order to wrap it.
2025-09-03 11:34:02 -04:00
Jonathan Amsterdam
063fb12149
mcp: unexport ToolFor (#402)
The rationale is provided on the issue.

Also, document the low-level nature of Server.AddTool. (drive-by change)

Fixes #401.
2025-09-03 11:33:40 -04:00
Jonathan Amsterdam
7769b2a959
mcp: set content to marshaled output (#398)
The ToolHandler constructed by ToolFor sets the result's Content to the
marshaled output, following the spec's suggestion.

See
https://modelcontextprotocol.io/specification/2025-06-18/server/tools#structured-content.

Also, set StructuredContent to the marshaled RawMessage to avoid a
double marshal.

Fixes #391.
2025-09-03 10:37:27 -04:00
Robert Findley
07b65d76a7
examples/server/distributed: a stateless distributed server
Add an example of a server that proxies HTTP requests to multiple
stateless streamable MCP backends.

For #148
2025-09-02 14:32:12 -04:00
Brad Hoekstra
24fc13eb88
cleanup: remove reference to deleted jsonschema package
Signed-off-by: Brad Hoekstra <bhoekstra@google.com>
2025-09-02 14:19:53 -04:00
Shusaku Yasoda
a3935c6be2
examples/server: add example MCP server with JWT and API key (#339)
This commit introduces a new example demonstrating the integration of
authentication middleware with an MCP server. The server supports both
JWT token and API key authentication, along with scope-based access
control for various MCP tools. Key features include token generation
endpoints, in-memory API key storage, and a health check endpoint.

New files added:
- `main.go`: Implements the MCP server and authentication logic.
- `go.mod` and `go.sum`: Manage dependencies for the project.
- `README.md`: Provides setup instructions, available endpoints, and
example usage.

This example serves as a reference for implementing secure access to MCP
tools.

Fixes #330
2025-09-02 11:49:46 -04:00
Jonathan Amsterdam
be0a00cd0a
examples/http: update to v0.3.0
Fix build breakage.

Fixes #383.
2025-09-01 09:24:30 -04:00
Adam Koszek
a617dcea31
mcp/examples: HTTP server example with a simple client built-in (#168)
I'm adding a practical example of an MCP with HTTP streaming: both
client and server. Those are useful for testing real-world applications.
2025-08-30 14:30:48 -04:00
Jonathan Amsterdam
7bfde44981
mcp: statically type the server-side tool params (#378)
Introduce CallToolParamsRaw on the server side, so that tool handlers
see in the type system that a tool's arguments are a json.RawMessage.

Fixes #377.
2025-08-30 08:16:06 -04:00
Robert Findley
8f11a86898
examples/client: add a loadtest command v0.3.1
Add a loadtest client example, to help confirm performance of our
streamable transport implementation.

For #190
2025-08-29 15:28:05 -04:00
Sam Thanawalla
ddaf35ed77
mcp/streamable: use event store to fix unbounded memory issues (#335)
This CL utilizes the event store to write outgoing messages and removes
the unbounded outgoing data structure.

It also adds a new interface [EventStore.Open]

For #190
2025-08-29 12:54:51 -04:00
Huabing (Robin) Zhao
f6118aaace
mcp: fix the type of the Complete handler
The Complete handler was returning an abstract Result type, rather than concrete CompleteResult type.

Fixes #375
2025-08-29 10:06:23 -04:00
Takeshi Yoneda
a76bae3a11 address review comments
Signed-off-by: Takeshi Yoneda <t.y.mathetake@gmail.com>
2025-08-27 16:03:32 -04:00
Takeshi Yoneda
c24d9856c4 mcp/streamable: fixes broken DELETE request on connection close
Signed-off-by: Takeshi Yoneda <t.y.mathetake@gmail.com>
2025-08-27 16:03:32 -04:00
Sam Thanawalla
392f719bd1
mcp/examples: move server example into example folder (#357)
For better organization.
2025-08-26 09:13:30 -04:00
Jonathan Amsterdam
03c5113471
examples/server/memory: fix misleading code (#369)
Tools shouldn't both set StructuredContent and return a typed output.
Remove the assignment.
2025-08-25 16:48:10 -04:00
Jim Clark
c1c22925da
relax requirements on resource URIs (#365)
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>
```
2025-08-25 15:00:36 -04:00
Jonathan Amsterdam
73dd76b614
go.mod: update to fixed jsonschema (#370)
Update to a version that doesn't copy descriptions of subschemas.

Fixes #366.
2025-08-25 14:00:24 -04:00
Rob Findley
f37e549e25 mcp: polish package doc for v0.3.0 v0.3.0
Do a pass through the package doc for v0.3.0.
2025-08-22 16:03:15 -04:00
Hongxiang Jiang
fb69971650
mcp: cleanup transport after keepalive ping fails
An onClose function is passed to the ServerSession and ClientSession to
help cleanup resources from the caller.

The onClose function will be executed as part of the ServerSession and
ClientSession closure.

Fixes #258
2025-08-22 15:26:52 -04:00
Rob Findley
9754a2aa86 examples: add an everything example, and simplify hello
Our 'hello' example should be as simple as possible. On the other hand,
we should have an 'everything' example that exercises (almost)
everything we offer.

Using the everything example, I did some final testing using the
inspector. This turned up a couple rough edges related to JSON null that
I addressed by preferring empty slices.

For #33
2025-08-22 14:00:37 -04:00
Jonathan Amsterdam
c631641296
mcp: check output schema type (#358)
Server.AddTool now checks that an output schema, if any, has type
"object".

Also add doc and a test.
2025-08-22 11:35:50 -04:00
Sam Thanawalla
d16ce9c25f
mcp/examples: moves middleware examples into example folder (#356)
For better organization.
2025-08-22 11:18:05 -04:00
Jonathan Amsterdam
b891d95361
mcp: example middleware wrapping ToolHandler (#351)
Add to the middleware example to show how to wrap a ToolHandler.

This middleware is very close to, but not the same as, wrapping a
ToolHandler directly. The only difference is that the middleware wraps
Server.callTool, which looks up the tool by name in the server's list
and then calls the handler. That lookup (plus other intervening
middleware, of course) is all that distinguishes this way of wrapping
from a more direct wrapping.
2025-08-22 11:05:03 -04:00
Jonathan Amsterdam
18c96d6912
mcp: enforce input schema type "object" (#349)
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.
2025-08-22 11:04:44 -04:00
Jonathan Amsterdam
4587941994
mcp: add Request.GetExtra (#350) 2025-08-22 11:04:01 -04:00
Sam Thanawalla
42f419fff4
mcp/examples: move elicitation example into example folder (#354)
Rename and move the example into the examples folder.
2025-08-22 11:01:48 -04:00
Jonathan Amsterdam
e3e8aaf024
mcp: align PromptHandler args with other handlers (#348)
The second arg is a GetPromptRequest.

Fixes #300.
2025-08-22 10:44:05 -04:00
Rob Findley
5fd06ae8b7 mcp: unexport InitializeClientRequest
This request is synthetic, and should not be observed by the user.
Unexport it and rename InitializeServerRequest to just
InitializeRequest.
2025-08-22 10:40:57 -04:00
Kartik Verma
c058c6a93b
feat/Issue-13: elicitation support (#188)
fixes: #13 

 Implements elicitation functionality from MCP 2025-06-18 specification.

 Changes
 - Add ElicitParams and ElicitResult protocol types 
- Add ServerSession.Elicit() method and ClientOptions.ElicitationHandler
 - Schema validation enforces top-level properties only
 - Support for accept/decline/cancel actions with progress tokens

Tests
 - Integration test in TestEndToEnd
 - Schema validation, error handling, and capability declaration tests
2025-08-22 09:29:51 -04:00
Jonathan Amsterdam
62db914082
mcp: export ToolFor (#347)
This is needed so clients can modify tool schemas, and not merely to
wrap ToolHandlers.

(A consequence of returning a copy of Tool instead of modifying it.)
2025-08-21 17:54:17 -04:00
Robert Findley
dd8e3af18d
README: soften the warning, and reference roadmap (#345)
We can warn a little less loudly against using the SDK.
2025-08-21 17:41:38 -04:00
Jonathan Amsterdam
bf79d784b9
mcp: remove references to ClientRequest[T] for concrete T (#343)
See related PR about ServerRequest[T].
2025-08-21 15:24:58 -04:00
Robert Findley
d8e18b34cf
mcp: fix bugs handling pointer types (#344)
Some bad merging in #338 led to a bad bug in the handling of structured
output for pointer output types. Add a conformance test and fix the bug.
2025-08-21 14:43:22 -04:00
Jonathan Amsterdam
6378df6f24
all: remove ServerRequest[T] for concrete T (#342)
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.
2025-08-21 12:10:53 -04:00
Robert Findley
43ad1eb8b4
mcp: treat pointers equivalently to non-pointers when deriving schema
As reported in #199 and #200, the fact that we return a possibly "null"
schema for pointer types breaks various clients, which expect schemas to
be of type "object". This is an unfortunate footgun. For now, assume
that the user wants us to treat pointers equivalently to non-pointers.
If we want to change this behavior in the future, we can do so behind an
option.

+ a test

Also fix the handling of nil results in the case where the output schema
is non-nil: we must provide structured content in this case. (This was
causing the test to fail).

Fixes #199
Fixes #200
2025-08-21 10:57:28 -04:00