feat: Add update_pull_request tool

[monotykamary]

This pull request introduces the update_pull_request tool to the GitHub MCP server.

Changes:

• Added the UpdatePullRequest function in pkg/github/pullrequests.go to define the tool and its handler.
• Added the OptionalParamOK helper function in pkg/github/server.go.
• Registered the new tool in pkg/github/server.go.
• Added unit tests for the UpdatePullRequest tool in pkg/github/pullrequests_test.go.
• Fixed test failures related to request body expectations for the base field during testing.

The new tool allows users to update the following fields of an existing pull request:

• title
• body
• state (open/closed)
• base branch
• maintainer_can_modify flag

This was updated through the update_pull_request tool GitHub MCP server (^6).

[Copilot]

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (2)

pkg/github/pullrequests.go:156

• The error message returned for missing update parameters includes a trailing period. Consider unifying the error message text (e.g. 'No update parameters provided') to match test expectations and ensure consistency.

if !updateNeeded {

pkg/github/server.go:129

• [nitpick] The error message in the optionalParamOk helper could be clarified by explicitly stating the expected and actual types, making debugging easier when a parameter has an unexpected type.

if !ok {

[monotykamary]

[juruen]

Thank you so much for your PR! ❤️

I added a few comments, mainly to the new optionalParamOk function.

I'm not super hyped about the name, but naming is hard :)

In general, this tool has shown that the current optionalParam falls short when you actually want to know whether the parameter actually exists.

This is probably out of the scope for this PR, but I'm going to open an issue to discuss how we can handle optional parameters better. I have the feeling that it might make sense that the optionalParam to always return whether the param was passed. But again, that might be a separate discussion.

[juruen]

@monotykamary thank you for your changes, just one more thing, would you mind updating the README to list the new tool?

[monotykamary]

Oh right, forgot about that part. Should be up 👍

[juruen]

LGTM! 🚀

Thank you so much for your contribution!

[juruen]

@monotykamary can you please update your branch with latest main, and we we'll be good to merge!

[monotykamary]

@juruen I've updated it to follow the newer named export convention, should be good 👍

[juruen]

@monotykamary I can't update your branch because you probably set maintainer_can_modify to false, so you need to do it before we can merge it.

[monotykamary]

Aha my bad. @juruen should be set. This PR was made by the MCP server, should probably note somewhere to add mcp.DefaultBool(true), to allow maintainer edits by default.

[juruen]

Aha my bad. @juruen should be set. This PR was made by the MCP server

I figured that as well 😄

should probably note somewhere to add mcp.DefaultBool(true), to allow maintainer edits by default.

Agreed!