Add discussion metadata fields to get_discussion tool

[Higangssh]

Problem

The get_discussion tool lacked important metadata fields already available in get_issue, making it difficult
to determine discussion status.

Solution

Added discussion metadata fields:

• closed - Boolean indicating if the discussion is closed
• isAnswered - Whether discussion has an accepted answer
• answerChosenAt - Timestamp when answer was selected (optional)

Implementation Details

Modified GetDiscussion to return map[string]interface{} instead of github.Discussion struct because
go-github v74's Discussion type lacks isAnswered and answerChosenAt fields. This approach mirrors existing
functions: ListDiscussions and GetDiscussionComments use similar patterns.

Changes Made

• Updated Discussion field mappings to match GitHub GraphQL API schema
• Replaced non-existent State field with Closed (Boolean)
• Removed non-existent AnsweredAt field
• Using AnswerChosenAt for answer timestamp
• Added nil checks for optional timestamp fields
• Updated all test cases and mock data
• All tests passing ✅

Testing

All tests pass with updated snapshots. Linter reports no issues. Backward compatibility verified.

Fixes #1303

[tommaso-moro]

Hi @Higangssh thank you for your work on this. I have tested it locally and it is not working (screenshot below), it looks like some of the fields are invalid. For example, State, IsAnswered and AnsweredAt don't exist on Discussion.

Instead of State you can use the closed field and then update the response map to use "closed": bool(d.Closed). As to the other two, I would recommend using answerChosenAt, and deriving isAnswered from it (specifically, it will be equivalent to answerChosenAt != nil).

I also recommend using the official GitHub GraphQL API Explorer to play around with the query and see which fields are available and what they return.

If you can, it would be great if you could update this PR. Otherwise, I am also happy to do it if you prefer. Thank you!

[tommaso-moro]

I believe State, AnsweredAt and IsAnswered are not valid fields for the Discussion type

[Higangssh]

Hi @tommaso-moro, thank you so much for the detailed review and suggestions!

I've updated the PR following your recommendations:

• ✅ State → Closed (Boolean)
• ✅ AnsweredAt → Removed (using answerChosenAt instead)

Regarding isAnswered:

Following your suggestion to use the GraphQL API Explorer, I tested the available fields and found that isAnswered is actually a valid field in the Discussion type.

Evidence:

1. Official Documentation: The GitHub GraphQL Reference lists isAnswered (Boolean) as a field for Discussion objects.

2. GraphQL Query Test: I tested with both answered and unanswered discussions:

   query {
     repository(owner: "github", name: "github-mcp-server") {
       discussion(number: 1248) {
         isAnswered
         answerChosenAt
       }
     }
   }

• Answered discussion (1248): { "isAnswered": true, "answerChosenAt": "2025-10-20T09:57:37Z" }
• Unanswered discussion (1088): { "isAnswered": false, "answerChosenAt": null }

Both queries executed successfully without errors, confirming that isAnswered is valid.

Given this, I've kept isAnswered as a direct field query rather than deriving it. This approach uses the field that GitHub's API provides and is more efficient than client-side calculation.

Would you prefer I derive it from answerChosenAt != nil instead, or is this approach acceptable?

Thank you again for your help! 🙏

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