## Pull request overview

Pull request overview

This PR extends the issues tool surface to support reading and writing GitHub Issues 2.0 custom field values, aligning issue_read/issue_write behavior with the newer REST/GraphQL capabilities introduced alongside the go-github upgrade.

Changes:

• Added issue_fields input to issue_write, including name-based resolution of field IDs and (for single-select) option validation.
• Expanded issue_read output handling to include REST issue_field_values, and added best-effort GraphQL enrichment to normalize to field_values where possible.
• Updated minimal/DTO types and unit tests to cover issue field value parsing and write request shaping.

Copilot's findings

	var fieldValuesByID map[string][]MinimalFieldValue
	if len(result.Issues) > 0 {
		gqlClient, err := deps.GetGQLClient(ctx)
		if err != nil {
			return utils.NewToolResultErrorFromErr(errorPrefix+": failed to get GitHub GraphQL client", err), nil
		}
		fieldValuesByID, err = fetchIssueFieldValuesByNodeID(ctx, gqlClient, result.Issues)
		if err != nil {
			return ghErrors.NewGitHubGraphQLErrorResponse(ctx, errorPrefix+": failed to fetch issue field values", err), nil
		}
	}

• Files reviewed: 9/9 changed files
• Comments generated: 2

Originally posted by @copilot-pull-request-reviewer in https://github.com/github/github-mcp-server/pull/2551#pullrequestreview-4365741362

Start with pkg/github/issues.go and pkg/github/issues_test.go; the overview describes issue field value handling and flags a possible regression in searchIssuesHandler. Check the feature-flag behavior and its tests first. Done means search enrichment respects the documented feature-flag behavior while the listed read/write cases remain covered.