feat(web): acknowledge review command comments with a reaction

Adds a configurable acknowledgment reaction/emoji to the triggering
comment when the review agent receives a `/review` command, so users
get immediate feedback that the request was received.

- GitHub: reacts to the issue comment via the reactions API (default: `eyes`)
- GitLab: awards an emoji on the MR note via `MergeRequestNoteAwardEmojis`
- New `REVIEW_AGENT_ACK_REACTION` env var (default: `eyes`) controls the reaction
- Acknowledgment failures are logged as warnings and do not block the review

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Gavin Williams

docs/docs/configuration/environment-variables.mdx

@@ -70,11 +70,12 @@ The following environment variables allow you to configure your Sourcebot deploy
 | `GITHUB_REVIEW_AGENT_APP_PRIVATE_KEY_PATH` | `-` | <p>The container relative path to the private key file for the GitHub App used by the review agent.</p> |
 | `GITHUB_REVIEW_AGENT_APP_WEBHOOK_SECRET` | `-` | <p>The webhook secret for the GitHub App used by the review agent.</p> |
 | `OPENAI_API_KEY` | `-` | <p>The OpenAI API key used by the review agent.</p> |
+| `REVIEW_AGENT_ACK_REACTION` | `eyes` | <p>The reaction/emoji added to a comment when the review agent acknowledges receipt of the review command.</p> |
 | `REVIEW_AGENT_API_KEY` | `-` | <p>The Sourcebot API key used by the review agent.</p> |
 | `REVIEW_AGENT_AUTO_REVIEW_ENABLED` | `false` | <p>Enables/disables automatic code reviews by the review agent.</p> |
 | `REVIEW_AGENT_LOGGING_ENABLED` | `true` | <p>Enables/disables logging for the review agent. Logs are saved in `DATA_CACHE_DIR/review-agent`</p> |
 | `REVIEW_AGENT_REVIEW_COMMAND` | `review` | <p>The command used to trigger a code review by the review agent.</p> |
 
 ### Overriding environment variables from the config
 
-You can override environment variables from the config file by using the `environmentOverrides` property. See [this doc](/docs/configuration/config-file#overriding-environment-variables-from-the-config) for more info.
+You can override environment variables from the config file by using the `environmentOverrides` property. See [this doc](/docs/configuration/config-file#overriding-environment-variables-from-the-config) for more info.

docs/docs/features/agents/review-agent.mdx

@@ -141,7 +141,8 @@ You can also trigger a review manually by commenting `/review` on any PR or MR.
 
 | Variable | Default | Description |
 |---|---|---|
+| `REVIEW_AGENT_ACK_REACTION` | `eyes` | Reaction/emoji added to acknowledge receipt of the review command |
 | `REVIEW_AGENT_AUTO_REVIEW_ENABLED` | `false` | Automatically review new and updated PRs/MRs |
-| `REVIEW_AGENT_REVIEW_COMMAND` | `review` | Comment command that triggers a manual review (without the `/`) |
-| `REVIEW_AGENT_MODEL` | first configured model | `displayName` of the language model to use for reviews |
 | `REVIEW_AGENT_LOGGING_ENABLED` | unset | Write prompt and response logs to disk for debugging |
+| `REVIEW_AGENT_MODEL` | first configured model | `displayName` of the language model to use for reviews |
+| `REVIEW_AGENT_REVIEW_COMMAND` | `review` | Comment command that triggers a manual review (without the `/`) |

packages/shared/src/env.server.ts

@@ -235,10 +235,11 @@ const options = {
         GITLAB_REVIEW_AGENT_TOKEN: z.string().optional(),
         GITLAB_REVIEW_AGENT_HOST: z.string().default('gitlab.com').transform(s => s.replace(/^https?:\/\//, '').replace(/\/+$/, '')).refine(s => /^[a-z0-9.-]+$/i.test(s), { message: 'invalid hostname' }),
         // Review agent config
-        REVIEW_AGENT_MODEL: z.string().optional(),
+        REVIEW_AGENT_ACK_REACTION: z.string().default('eyes'),
         REVIEW_AGENT_API_KEY: z.string().optional(),
-        REVIEW_AGENT_LOGGING_ENABLED: booleanSchema.default('true'),
         REVIEW_AGENT_AUTO_REVIEW_ENABLED: booleanSchema.default('false'),
+        REVIEW_AGENT_LOGGING_ENABLED: booleanSchema.default('true'),
+        REVIEW_AGENT_MODEL: z.string().optional(),
         REVIEW_AGENT_REVIEW_COMMAND: z.string().default('review'),
 
         ANTHROPIC_API_KEY: z.string().optional(),

packages/web/src/app/api/(server)/webhook/route.ts

@@ -185,6 +185,18 @@ export const POST = async (request: NextRequest) => {
                 const owner = body.repository.owner.login;
 
                 const octokit = await githubApp.getInstallationOctokit(body.installation.id);
+
+                try {
+                    await octokit.rest.reactions.createForIssueComment({
+                        owner,
+                        repo: repositoryName,
+                        comment_id: body.comment.id,
+                        content: env.REVIEW_AGENT_ACK_REACTION as Parameters<typeof octokit.rest.reactions.createForIssueComment>[0]['content'],
+                    });
+                } catch (error) {
+                    logger.warn(`Failed to add acknowledgment reaction to GitHub comment: ${error}`);
+                }
+
                 const { data: pullRequest } = await octokit.rest.pulls.get({
                     owner,
                     repo: repositoryName,
@@ -246,6 +258,17 @@ export const POST = async (request: NextRequest) => {
             if (noteBody === `/${env.REVIEW_AGENT_REVIEW_COMMAND}`) {
                 logger.info('Review agent review command received on GitLab MR, processing');
 
+                try {
+                    await gitlabClient.MergeRequestNoteAwardEmojis.award(
+                        parsed.data.project.id,
+                        parsed.data.merge_request.iid,
+                        parsed.data.object_attributes.id,
+                        env.REVIEW_AGENT_ACK_REACTION,
+                    );
+                } catch (error) {
+                    logger.warn(`Failed to add acknowledgment emoji to GitLab note: ${error}`);
+                }
+
                 const mrPayload: GitLabMergeRequestPayload = {
                     object_kind: "merge_request",
                     object_attributes: {

packages/web/src/features/agents/review-agent/types.ts

@@ -87,6 +87,7 @@ export type GitLabMergeRequestPayload = z.infer<typeof gitLabMergeRequestPayload
 export const gitLabNotePayloadSchema = z.object({
     object_kind: z.literal('note'),
     object_attributes: z.object({
+        id: z.number(),
         note: z.string(),
         noteable_type: z.literal('MergeRequest'),
     }),