Add reaction tools for issues and pull requests by timrogers · Pull Request #2732 · github/github-mcp-server · GitHub

Summary

Add reaction support for issues, issue comments, and pull request review comments while keeping standalone reaction tools behind the granular tool feature flags.

Default users can add reactions through existing comment tools to avoid adding more default tools:

add_issue_comment can add an issue/PR comment, add a reaction to an issue/PR, add a reaction to an issue/PR timeline comment, or combine a comment with a reaction.
add_reply_to_pull_request_comment can reply to a pull request review comment, add a reaction to a pull request review comment, or do both.

Granular users also get standalone tools:

add_issue_reaction
add_issue_comment_reaction
add_pull_request_review_comment_reaction

Why

Reactions are a fundamental part of GitHub's interaction model. Clients should be able to add reactions programmatically just as they can create issues, comments, and reviews, without increasing the default tool surface more than necessary.

What changed

Added granular standalone reaction tools for issues, issue comments, and PR review comments.
Extended default comment tools with optional reaction parameters.
Clarified numeric comment ID requirements, especially for PR review comments where callers must use the numeric #discussion_r... ID rather than a GraphQL review thread node ID.
Added validation so reaction/comment combinations are explicit and do not silently ignore comment IDs.
Ordered combined reaction+comment operations so the idempotent reaction happens before creating the non-idempotent comment/reply, reducing duplicate-comment risk on retries.
Updated tests, toolsnaps, and generated docs.

MCP impact

New tool added
- Three standalone reaction tools are added to granular issue and pull request toolsets.
Existing tool changed
- add_issue_comment and add_reply_to_pull_request_comment now support reactions.

Prompts tested (tool changes only)

"Add a reaction to issue 42 in my-repo"
"Add a reaction to the issue comment I just made"
"Add a reaction to the PR review comment feedback"
"Reply to this PR review comment and add a rocket reaction"

Security / limits

No security or limits impact
- Reactions follow existing GitHub API permissions and use the same client authentication/error handling as other write tools.

Tool renaming

I am not renaming existing MCP tools as part of this PR

Lint & tests

Linted locally with ./script/lint
Tested locally with ./script/test

Docs

Updated (README / docs / examples)
- README.md and generated docs updated via script/generate-docs.
- Toolsnaps updated in pkg/github/__toolsnaps__/.

Closes #2757

Pull request overview

This PR adds three new MCP write tools that let clients create emoji reactions on GitHub issues, issue comments, and pull request review comments, extending the server’s “write” surface area to cover a core GitHub interaction.

Changes:

Added three new tools: add_issue_reaction, add_issue_comment_reaction, and add_pull_request_review_comment_reaction.
Wired the tools into the global tool inventory and added handler tests with mocked HTTP endpoints.
Updated generated documentation and added new tool schema snapshots (__toolsnaps__).

Show a summary per file

File	Description
README.md	Documents the three new tools and their parameters in the generated tool listing.
pkg/github/tools.go	Registers the three new tools in AllTools so they’re available to clients.
pkg/github/issues_granular.go	Implements add_issue_reaction and add_issue_comment_reaction tool schemas and handlers.
pkg/github/pullrequests_granular.go	Implements add_pull_request_review_comment_reaction tool schema and handler.
pkg/github/helper_test.go	Adds mocked endpoint patterns for the reactions REST endpoints.
pkg/github/granular_tools_test.go	Adds toolsnap coverage and handler tests for the new reaction tools.
pkg/github/toolsnaps/add_issue_reaction.snap	New snapshot for add_issue_reaction tool schema.
pkg/github/toolsnaps/add_issue_comment_reaction.snap	New snapshot for add_issue_comment_reaction tool schema.
pkg/github/toolsnaps/add_pull_request_review_comment_reaction.snap	New snapshot for add_pull_request_review_comment_reaction tool schema.

Copilot's findings

Files reviewed: 9/9 changed files
Comments generated: 3

Implement three granular-only tools for adding emoji reactions: - add_issue_reaction: Add reaction to an issue - add_issue_comment_reaction: Add reaction to an issue comment - add_pull_request_review_comment_reaction: Add reaction to a PR review comment All tools are feature-flagged with FeatureFlagEnable set to enable them only when clients request granular toolsets. Tools use go-github's Reactions service and return minimal ID response on success (HTTP 201). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Remove feature flag gates from reaction tools so they're available to all clients regardless of granular toolset preference. Reaction tools are naturally atomic operations and work equally well in both modes. Updates test expectations to exclude reaction tools from granular-only test assertions, since they're now always available. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Looks good to me 🚀

Tested manually locally and this is all working. We could consider adding tools to remove reactions, but I think this is a good incremental step and we can choose to add more later.

Return reaction URLs in minimal responses and clarify issue tools apply to pull requests where applicable. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

internal/ghmcp/server_test.go.github/actions/build-ui/action.ymlREADME.mdhttps://github.com/modelcontextprotocol/modelcontextprotocol/issues/1489

Keep the standalone reaction tools behind granular feature flags to avoid expanding the default tool count. Add optional reaction support to the existing issue comment and pull request comment reply tools, requiring at least one of body or reaction. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Document that PR review comment reaction inputs require the numeric review comment ID, not the GraphQL review thread node ID returned by review thread APIs. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Add optional comment_id support so the default add_issue_comment tool can react to a specific issue or pull request comment without exposing a separate default reaction tool. Keep body creation tied to issue_number and require reaction targets to provide either issue_number or comment_id. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot's findings

Files reviewed: 16/16 changed files
Comments generated: 4

Apply reactions before creating comments or replies so retrying a failed combined call cannot duplicate the non-idempotent comment operation. Also reject issue comment IDs without a reaction target to avoid silently ignoring the field. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot's findings

Files reviewed: 16/16 changed files
Comments generated: 6

Copilot's findings

Comments suppressed due to low confidence (1)

pkg/github/issues_test.go:631

In this test, the failure case sets expectedErrMsg but the assertion path does not verify the tool call actually returned an error result (result.IsError). This can allow regressions where the tool returns a non-error result containing the substring. Align the failure handling with the rest of the suite by asserting result.IsError and reading the error via getErrorResult().

			expectedErrMsg: "failed to create comment",
		},
	}

	for _, tc := range tests {

Files reviewed: 16/16 changed files
Comments generated: 0 new

Make issue_number required on the consolidated add_issue_comment tool even when reacting to a specific issue comment, keeping the default tool input shape explicit. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot's findings

Files reviewed: 16/16 changed files
Comments generated: 1

Return structured GitHub API errors for issue comment creation failures and assert MCP error results in tests. Also reject comment_id with body on the consolidated comment tool to avoid ambiguous comment-plus-comment-reaction requests. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Review details

Files reviewed: 16/16 changed files
Comments generated: 2
Review effort level: Low

Use the required issue_number to verify issue comment reaction targets before creating the reaction, and remove overlapping add_issue_comment test coverage. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Review details

Files reviewed: 16/16 changed files
Comments generated: 3
Review effort level: Low

Reject non-positive issue and pull request comment IDs in handlers and add the missing schema minimum for pull request review comment IDs. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Review details

Files reviewed: 16/16 changed files
Comments generated: 6
Review effort level: Low

…nning-reaction-tools # Conflicts: # pkg/github/helper_test.go

timrogers requested a review from a team as a code owner June 19, 2026 16:06

Copilot AI review requested due to automatic review settings June 19, 2026 16:06

Copilot started reviewing on behalf of timrogers June 19, 2026 16:06 View session

Copilot AI reviewed Jun 19, 2026

View reviewed changes

Comment thread pkg/github/issues_granular.go

Comment thread pkg/github/issues_granular.go Outdated

Comment thread pkg/github/pullrequests_granular.go Outdated

timrogers and others added 4 commits June 19, 2026 17:25

Update toolsnaps with aligned reaction tool descriptions

774b75b

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Align reaction tool descriptions with codebase style

94c6f2c

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

timrogers force-pushed the timrogers/planning-reaction-tools branch from 44c2a5e to 94c6f2c Compare June 19, 2026 16:26

A-Georgiou previously approved these changes Jun 19, 2026

View reviewed changes

Improve reaction tool responses and wording

30da9da

Return reaction URLs in minimal responses and clarify issue tools apply to pull requests where applicable. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

timrogers dismissed A-Georgiou’s stale review via 30da9da June 19, 2026 17:28

A-Georgiou previously approved these changes Jun 19, 2026

View reviewed changes

phillipschandler19-web reviewed Jun 20, 2026

View reviewed changes

SamMorrowDrums dismissed A-Georgiou’s stale review via 009bb7b June 23, 2026 12:29

This was referenced Jun 23, 2026

Track: reaction tools for issues and pull requests (#2732) #2757

Closed

Track: reaction tools for issues and pull requests (#2732) #2758

Closed

Clarify PR review comment IDs for reactions

e6276cf

Document that PR review comment reaction inputs require the numeric review comment ID, not the GraphQL review thread node ID returned by review thread APIs. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

SamMorrowDrums mentioned this pull request Jun 23, 2026

Track: reaction tools for issues and pull requests (#2732) #2759

Closed

4 tasks

SamMorrowDrums requested a review from Copilot June 23, 2026 13:37

Merge branch 'main' into timrogers/planning-reaction-tools

9908fbf

Copilot started reviewing on behalf of SamMorrowDrums June 23, 2026 13:38 View session

Copilot AI reviewed Jun 23, 2026

View reviewed changes

SamMorrowDrums requested a review from Copilot June 23, 2026 19:32

Copilot started reviewing on behalf of SamMorrowDrums June 23, 2026 19:33 View session

Copilot AI reviewed Jun 23, 2026

View reviewed changes

SamMorrowDrums requested a review from Copilot June 23, 2026 19:45

Copilot started reviewing on behalf of SamMorrowDrums June 23, 2026 19:45 View session

Copilot AI reviewed Jun 23, 2026

View reviewed changes

Require issue number for comment reactions

9855c06

Make issue_number required on the consolidated add_issue_comment tool even when reacting to a specific issue comment, keeping the default tool input shape explicit. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

SamMorrowDrums requested a review from Copilot June 24, 2026 18:49

Copilot started reviewing on behalf of SamMorrowDrums June 24, 2026 18:49 View session

Copilot AI reviewed Jun 24, 2026

View reviewed changes

SamMorrowDrums and others added 2 commits June 26, 2026 08:26

Merge branch 'main' into timrogers/planning-reaction-tools

ca55793

SamMorrowDrums requested a review from Copilot June 26, 2026 06:26

Copilot started reviewing on behalf of SamMorrowDrums June 26, 2026 06:27 View session

Copilot AI reviewed Jun 26, 2026

View reviewed changes

Comment thread pkg/github/issues.go

Comment thread pkg/github/issues_test.go

Validate issue comment reaction target

e522c77

Use the required issue_number to verify issue comment reaction targets before creating the reaction, and remove overlapping add_issue_comment test coverage. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

SamMorrowDrums requested a review from Copilot June 26, 2026 06:36

Copilot started reviewing on behalf of SamMorrowDrums June 26, 2026 06:36 View session

Copilot AI reviewed Jun 26, 2026

View reviewed changes

Validate positive comment IDs

ea14878

Reject non-positive issue and pull request comment IDs in handlers and add the missing schema minimum for pull request review comment IDs. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

SamMorrowDrums requested a review from Copilot June 26, 2026 06:41

Copilot started reviewing on behalf of SamMorrowDrums June 26, 2026 06:42 View session

Copilot AI reviewed Jun 26, 2026

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CZNetworks mentioned this pull request Jun 26, 2026

## Copilot's findings microsoft/vscode#323065

Closed

Merge remote-tracking branch 'origin/main' into pr/2732/timrogers/pla…

95737a9

…nning-reaction-tools # Conflicts: # pkg/github/helper_test.go

SamMorrowDrums approved these changes Jun 26, 2026

View reviewed changes

SamMorrowDrums merged commit 8cd03c0 into github:main Jun 27, 2026
13 checks passed

BrewTestBot mentioned this pull request Jun 27, 2026

github-mcp-server 1.5.0 Homebrew/homebrew-core#290133

Merged

gastrodon mentioned this pull request Jun 27, 2026

[backport] Emoji reaction tools for issues and pull requests (upstream v1.5.0) auto-patcher/github-mcp-server#24

Closed

github-actions Bot mentioned this pull request Jun 28, 2026

[ca] CLI Version Updates: GitHub MCP Server v1.5.0, MCP Gateway v0.3.31 github/gh-aw#42022

Closed

Copilot AI mentioned this pull request Jun 28, 2026

Bump default GitHub MCP Server to v1.5.0 and MCP Gateway to v0.3.31 github/gh-aw#42026

Closed

github-actions Bot mentioned this pull request Jun 29, 2026

[ca] CLI Updates: GitHub MCP Server v1.5.0, Codex 0.142.4 github/gh-aw#42196

Closed

Copilot AI mentioned this pull request Jun 29, 2026

Update GitHub MCP Server v1.5.0, Codex 0.142.4 github/gh-aw#42211

Merged

+              				createdComment, resp, err := client.Issues.CreateComment(ctx, owner, repo, issueNumber, comment)
               				if err != nil {
-              					return utils.NewToolResultErrorFromErr("failed to read response body", err), nil, nil
+              					return utils.NewToolResultErrorFromErr("failed to create comment", err), nil, nil
+              				}

               		ListIssueFields(t),
               		IssueWrite(t),
               		AddIssueComment(t),
+              		AddIssueReaction(t),
+              		AddIssueCommentReaction(t),

+              			if hasBody && !hasIssueNumber {
+              				return utils.NewToolResultError("issue_number is required when body is provided"), nil, nil
+              			}
+              			if hasReaction && !hasIssueNumber && !hasCommentID {
+              				return utils.NewToolResultError("issue_number or comment_id is required when reaction is provided"), nil, nil
+              			}
+              			if hasCommentID && !hasReaction {
+              				return utils.NewToolResultError("comment_id can only be provided when reaction is provided"), nil, nil
+              			}

@@ @@ -618,10 +621,10 @@ func Test_AddIssueComment(t *testing.T) { @@
               				"owner":        "owner",
               				"repo":         "repo",
               				"issue_number": float64(42),
-              				"body":         "",
+              				"body":         "This is a test comment",
               			},
               			expectError:    false,
-              			expectedErrMsg: "missing required parameter: body",
+              			expectedErrMsg: "failed to create comment",
               		},

+              				commentID, err = RequiredBigInt(args, "comment_id")
+              				if err != nil {
+              					return utils.NewToolResultError(err.Error()), nil, nil
+              				}
+              				hasCommentID = true

+              // AddIssueReaction adds a reaction to an issue or pull request.
+              func AddIssueReaction(t translations.TranslationHelperFunc) inventory.ServerTool {
+              	st := NewTool(

+              // AddPullRequestReviewCommentReaction adds a reaction to a pull request review comment.
+              func AddPullRequestReviewCommentReaction(t translations.TranslationHelperFunc) inventory.ServerTool {
+              	st := NewTool(

+              				reactionResponse = &MinimalResponse{
+              					ID:  fmt.Sprintf("%d", reaction.GetID()),
+              					URL: fmt.Sprintf("%srepos/%s/%s/pulls/comments/%d/reactions/%d", client.BaseURL(), owner, repo, commentID, reaction.GetID()),
+              				}

+              			r, err := json.Marshal(MinimalResponse{
+              				ID:  fmt.Sprintf("%d", reaction.GetID()),
+              				URL: fmt.Sprintf("%srepos/%s/%s/issues/%d/reactions/%d", client.BaseURL(), owner, repo, issueNumber, reaction.GetID()),
+              			})

Add reaction tools for issues and pull requests by timrogers · Pull Request #2732 · github/github-mcp-server · GitHub

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Add reaction tools for issues and pull requests - #2732

Add reaction tools for issues and pull requests#2732SamMorrowDrums merged 18 commits intogithub:maingithub/github-mcp-server:mainfrom timrogers:timrogers/planning-reaction-toolstimrogers/github-mcp-server:timrogers/planning-reaction-toolsCopy head branch name to clipboard

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timrogers commented Jun 19, 2026 • edited by SamMorrowDrums Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

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What changed

MCP impact

Prompts tested (tool changes only)

Security / limits

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Add reaction tools for issues and pull requests#2732
SamMorrowDrums merged 18 commits into
github:mainfrom
timrogers:timrogers/planning-reaction-tools

timrogers commented Jun 19, 2026 •
edited by SamMorrowDrums
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