gitlab-api

Gitlab Graphql Ops Cancel Pipeline

gitlab_graphql_ops_cancel_pipeline

Cancel a running GitLab pipeline via GraphQL by specifying the project ID or path and pipeline ID to stop unnecessary jobs.

Instructions

Cancel a running pipeline through GraphQL.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "project_id": "<project_id>",
      "pipeline_id": "<pipeline_id>"
    },
    "name": "gitlab_graphql_ops_cancel_pipeline"
  }
}

Input Schema

Name	Required	Description	Default
`project_id`	Yes	Project id or full path.
`pipeline_id`	Yes	Pipeline id.

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedv27.3.20Nov 7, 2026

removedInput schema / properties / params_json

Removed value: -{
-  "default": "{}",
-  "description": "JSON string of parameters to pass to the action.",
-  "type": "string"
-}

addedInput schema / properties / pipeline_id

Added value: +{
+  "description": "Pipeline id.",
+  "type": "integer"
+}

addedInput schema / properties / project_id

Added value: +{
+  "description": "Project id or full path.",
+  "type": "string"
+}

addedInput schema / required

Added value: +[
+  "project_id",
+  "pipeline_id"
+]

First observedv27.3.13Oct 25, 2026

TDQS

C2.9/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false and destructiveHint=false, so the mutation/non-destructive profile is covered, but the description adds nothing beyond that. It does not say what happens to in-flight jobs, whether cancellation is reversible, what error results for an already-finished pipeline, or what permissions are required.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with no filler or redundancy. It is efficient, though the brevity is under-specification rather than disciplined conciseness, which the other dimensions account for.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutation tool with no output schema, the description omits the outcome of the call: whether the pipeline transitions to canceled, whether child jobs are stopped, and how failures are surfaced. Given the sibling set contains several overlapping cancel/run/retry operations, this leaves meaningful ambiguity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with both project_id (id or full path) and pipeline_id documented in the schema, so the baseline of 3 applies. The description adds no meaning about identifier forms or constraints beyond what the schema already states.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description pairs a specific verb ("Cancel") with a specific resource ("a running pipeline") and notes the transport (GraphQL). An agent can tell what operation is performed, but nothing distinguishes it from nearby siblings such as gitlab_graphql_ops_retry_pipeline, gitlab_run_pipeline, or gitlab_cancel_project_job.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to choose this over the REST-style cancel or job-cancel siblings, no prerequisites stated, and no conditions under which it should not be used. The agent must infer the selection criteria entirely.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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