[backport] Emoji reaction tools for issues and pull requests (upstream v1.5.0)

[gastrodon]

Summary

Upstream v1.5.0 adds emoji reaction support across issues and pull requests via two layers:

Three new granular tools (gated behind FeatureFlagIssuesGranular / FeatureFlagPullRequestsGranular):

• add_issue_reaction — add a reaction (+1, -1, laugh, confused, heart, hooray, rocket, eyes) to an issue or pull request
• add_issue_comment_reaction — add a reaction to an issue or pull request comment by comment ID
• add_pull_request_review_comment_reaction — add a reaction to a PR review comment by numeric comment ID

Optional reaction params on existing default tools:

• add_issue_comment gains optional comment_id + content fields so an agent can react to a specific comment without enabling the granular toolset; body and comment_id/content are mutually exclusive on the same call
• add_reply_to_pull_request_comment gains an optional content field for the same reason

The three standalone tools live in issues_granular.go and pullrequests_granular.go. The default-tool extensions live in issues.go and pullrequests.go. Three new toolsnap files are added, and the two existing compound-tool snaps are updated.

Upstream reference

• version: v1.5.0
• commits: github@8cd03c0
• PR: Add reaction tools for issues and pull requests github/github-mcp-server#2732

Fork conflict

None. The fork's custom tools (issue_graph, set_project_item_status, add_issue_to_project, project field mutations) operate in entirely different areas. The reaction tools are purely additive.

Context

Reaction support was the last major missing surface for issue/PR interaction. Agents could read reaction counts (already in MinimalIssue.Reactions) but had no way to post reactions. The granular tools use client.Reactions.CreateIssueReaction, CreateIssueCommentReaction, and CreatePullRequestCommentReaction from go-github, all returning HTTP 201 with the reaction ID. The default-tool extensions reduce round-trips for agents that only need to react to a comment they just created.

[gastrodon]

Unified Changelog — v1.4.0 → v1.5.0

Context for all backport issues in this cycle.

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Stories

(none — all v1.5.0 changes are standalone)

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Standalone Features

[backport] Emoji reaction tools for issues and pull requests

• upstream version: v1.5.0
• type: feature
• standalone
• description: Three granular tools (add_issue_reaction, add_issue_comment_reaction, add_pull_request_review_comment_reaction) plus optional reaction params on the compound add_issue_comment and add_reply_to_pull_request_comment tools. Uses client.Reactions.* from go-github, returns HTTP 201 with reaction ID.
• upstream commits: 8cd03c0 (PR Add reaction tools for issues and pull requests github/github-mcp-server#2732)
• fork conflict: no — purely additive, no overlap with fork's project/graph tools

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No-ops (already applied in this fork before this cycle)

The fork already incorporated the following v1.5.0 changes prior to this patch cycle (they were present in the checked-out state and therefore require no action):

Change	upstream PR	status
get_parent method in issue_read	github#2726	✅ already in fork
delete:true fallback DELETE fix for issue fields	github#2755	✅ already in fork
Validate required params in add_comment_to_pending_review	github#2770	✅ already in fork
Issue dependency read/write tools (issue_dependency_read/write)	github#2751	✅ already in fork
stdio OAuth 2.1 login core library (internal/oauth)	github#2704	✅ already in fork
ui_get pagination cap (uiGetMaxPages = 10)	github#2766	✅ already in fork
MCP Apps show/defer refactor — remove show_ui, add shouldDeferToForm	github#2774	✅ already in fork
Issue write MCP App form params (add labels/assignees/milestone/type)	github#2767	✅ already in fork
Promote issue fields, remove LegacyIssueWrite and remote_mcp_issue_fields flag	github#2696	✅ already in fork
Dep bumps (hono, golang, node, actions/checkout)	github#2735 github#2752 github#2753 github#2754	n/a
Docs (OAuth install guides, lead with OAuth)	github#2776	n/a

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Bug Fixes

(all upstream v1.5.0 bug fixes were already applied in the fork — see no-ops table above)

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This cycle patches: v1.4.0 → v1.5.0
Issues created this cycle: #24

[gastrodon]

Design

Overview

Upstream PR github#2732 adds emoji reaction tools gated by the granular feature flags. The fork has those same flags already (FeatureFlagIssuesGranular, FeatureFlagPullRequestsGranular). We'll add the three reaction tools following the exact same patterns as the surrounding granular tools — no new patterns introduced.

Files to touch

pkg/github/issues_granular.go — append two functions after GranularAddSubIssue:

func GranularAddIssueReaction(getClient GetClientFn, t translations.TranslationHelperFunc) (tool mcp.Tool, handler server.ToolHandlerFunc)
func GranularAddIssueCommentReaction(getClient GetClientFn, t translations.TranslationHelperFunc) (tool mcp.Tool, handler server.ToolHandlerFunc)

Tool schema for add_issue_reaction:

• owner, repo (string, required)
• issue_number (int, required)
• content (string enum: +1, -1, laugh, confused, heart, hooray, rocket, eyes, required)

Implementation: client.Reactions.CreateIssueReaction(ctx, owner, repo, issueNumber, content) — returns MinimalResponse{ID, URL} from the reaction object. Gate: st.FeatureFlagEnable = FeatureFlagIssuesGranular.

Tool schema for add_issue_comment_reaction:

• owner, repo (string, required)
• comment_id (int64 via RequiredBigInt, required)
• content (same enum, required)

Implementation: client.Reactions.CreateIssueCommentReaction(ctx, owner, repo, commentID, content) — same MinimalResponse return. Gate: FeatureFlagIssuesGranular.

pkg/github/pullrequests_granular.go — append one function after GranularUnresolveReviewThread:

func GranularAddPullRequestReviewCommentReaction(getClient GetClientFn, t translations.TranslationHelperFunc) (tool mcp.Tool, handler server.ToolHandlerFunc)

Tool schema for add_pull_request_review_comment_reaction:

• owner, repo (string, required)
• comment_id (int64 via RequiredBigInt, required)
• content (same enum, required)

Implementation: client.Reactions.CreatePullRequestCommentReaction(ctx, owner, repo, commentID, content) — same MinimalResponse return. Gate: FeatureFlagPullRequestsGranular.

pkg/github/tools.go — register all three alongside existing granular tools:

// after GranularAddSubIssue(t):
GranularAddIssueReaction(t),
GranularAddIssueCommentReaction(t),
// after GranularAddPullRequestReviewComment(t):
GranularAddPullRequestReviewCommentReaction(t),

pkg/github/__toolsnaps__/ — three new snap files created automatically when tests run.

What we are NOT doing

• We are not modifying AddIssueComment or AddReplyToPullRequestComment to embed reactions. Those tools have a single clear purpose; reaction is a separate concern already expressed by the granular tools. The upstream PR added the reaction tools as standalone entries — that's the right decomposition.
• We are not adding a content parameter to the compound comment tools. Orthogonality: an agent wanting to comment AND react calls both tools.

Testing

Table-driven tests for all three new functions in issues_granular_test.go and pullrequests_granular_test.go using github_mock. Each test covers: valid call returns MinimalResponse; invalid content value returns validation error; missing required params return validation error. Run script/test to confirm toolsnaps regenerate cleanly.