GitLab ACTION
Create Merge Request Comment
Post a comment on a merge request. It works in three modes, chosen by which props you set: leave File Path and Discussion ID blank for a plain comment on the merge request as a whole; set File Path plus a line number to open an inline thread anchored to that line of the diff; or set Discussion ID to reply inside an existing thread. Use Get Merge Request Diffs first to get valid file paths and line numbers, and List Merge Request Discussions to get a Discussion ID to reply to. Line numbers follow GitLab's diff rules: for a line the merge request adds or leaves unchanged, pass New Line; for a line it removes, pass Old Line; for an unchanged context line, pass both. Getting that wrong is the usual cause of a rejected inline comment. To post several review comments at once, and optionally approve in the same step, use Create Merge Request Review instead. See the documentation
- Action
- Writes data
- OAuth
- SDK
- MCP
IMPLEMENTATION
Call this tool
Connect a user's GitLab account once, then configure and run Create Merge Request Comment from your backend or agent.
import { PipedreamClient } from "@pipedream/sdk"
const pd = new PipedreamClient({
projectId: process.env.PIPEDREAM_PROJECT_ID!,
clientId: process.env.PIPEDREAM_CLIENT_ID!,
clientSecret: process.env.PIPEDREAM_CLIENT_SECRET!,
projectEnvironment: "production",
})
const result = await pd.actions.run({
id: "gitlab-create-merge-request-comment",
externalUserId: "{external_user_id}", // any stable ID for this user in your system
configuredProps: {
gitlab: { authProvisionId: "apn_xxxxxxx" },
projectId: "Project",
mergeRequestIid: 10,
},
})
console.log(result)curl -X POST https://api.pipedream.com/v1/connect/{project_id}/actions/run \
-H "Content-Type: application/json" \
-H "X-PD-Environment: production" \
-H "Authorization: Bearer {access_token}" \
-d '{
"external_user_id": "{external_user_id}",
"id": "gitlab-create-merge-request-comment",
"configured_props": {
"gitlab": { "authProvisionId": "apn_xxxxxxx" },
"projectId": "Project",
"mergeRequestIid": 10
}
}'// accessToken: mint a short-lived token with the Connect SDK — see the MCP guide
const transport = new StreamableHTTPClientTransport(
new URL("https://remote.mcp.pipedream.net/v3"),
{
requestInit: {
headers: {
Authorization: `Bearer ${accessToken}`,
"x-pd-project-id": "{project_id}",
"x-pd-environment": "production",
"x-pd-external-user-id": "{external_user_id}", // any stable ID for this user in your system
"x-pd-app-slug": "gitlab",
},
},
},
)
const mcp = new Client({ name: "my-agent", version: "1.0.0" })
await mcp.connect(transport)
const { tools } = await mcp.listTools()
// listTools() hands your model this tool's input schema, so it can
// fill the arguments itself:
const result = await mcp.callTool({
name: "gitlab-create-merge-request-comment",
arguments: {
projectId: "Project",
mergeRequestIid: 10,
},
})SCHEMA
Inputs
Pipedream supplies the connected account. Your application provides the operation-specific values below. Dynamic inputs are resolved against that user's account.
| Property | Type | Description |
|---|---|---|
projectId Project | string | The project, given either as its path — group/project or group/subgroup/project, e.g. backend/payments — or as its numeric project ID. The path is what appears in the project URL and is usually what a user will name, so prefer it. A pasted GitLab URL also works. Use List Projects to find the path if you only know part of the name. Required |
mergeRequestIid Merge Request IID | integer | The merge request's internal ID — the !N shown in the GitLab UI and the number at the end of the merge request URL. This is not the id field, which is a much larger instance-wide number; passing id here returns a 404. Use List Merge Requests or Search Merge Requests to resolve the IID from a title, branch or author. Required |
body Body | string | The comment text. Supports GitLab-flavored Markdown, so code blocks, lists and suggestion blocks all work. Required |
discussionId Discussion ID | string | Set this to reply inside an existing thread instead of starting a new one. Get it from List Merge Request Discussions. Cannot be combined with File Path. Optional |
filePath File Path | string | Set this to anchor the comment to a line of the diff — the file's path after the change, exactly as new_path reports it in Get Merge Request Diffs (e.g. src/api/client.py). Leave blank for a comment on the merge request as a whole. Optional |
oldFilePath Old File Path | string | The file's path before the change, as old_path reports it in Get Merge Request Diffs. Only needed when the merge request renames the file — GitLab anchors a comment on a renamed file with both paths. Defaults to File Path. Optional |
newLine New Line | integer | Line number in the new version of the file. Use this for a line the merge request adds, and together with Old Line for an unchanged context line. Required with File Path unless Old Line is given. Optional |
oldLine Old Line | integer | Line number in the old version of the file. Use this for a line the merge request removes, and together with New Line for an unchanged context line. Optional |
REFERENCE
Tool details
Behavior hints are published with the component in the Pipedream registry and surface as MCP tool annotations, so an agent can reason about a tool before it calls it.
- Registry key
- gitlab-create-merge-request-comment
- Version
- 0.0.1
- App
- GitLab
- Authentication
- OAuth
- Read-only
- No
- Destructive
- No
- Open world
- Yes
- Source
- View on GitHub ↗