GitLab pipeline failure summary

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

readOnlyHint=true already tells the agent this is a safe read, so the bar is lower. The description still adds real behavior beyond that: allowed-to-fail jobs are surfaced but excluded from the failure count, and traces are truncated to the last script lines — an agent knows to expect evidence rather than full logs.

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

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

Two dense sentences with zero filler. The one-call diagnostic promise and the returned evidence are front-loaded, and the scoping notes (allowed-to-fail, default branch) follow logically.

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

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

Given an output schema exists, the description need not document return shape, yet it still characterizes the payload precisely. With all five parameters documented in-schema and the read-only annotation carrying the safety profile, nothing an agent needs to call this correctly is missing.

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

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

Schema description coverage is 100%, so every parameter including mr, branch, pipeline, repo, and cwd already carries an explanation. The description reinforces only the default behavior (current branch's latest pipeline), adding marginal semantics beyond the schema. Baseline 3 applies.

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

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

States a specific verb (diagnose) and resource (GitLab pipeline), then enumerates exactly what the diagnosis contains: status, failed jobs with GitLab's stated reasons, and the trailing script lines of each failed job's trace. This is clearly distinguishable from glab_ci_status, which the description implies is the shallower status-only view.

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

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

"Diagnose a GitLab pipeline in one call" plus the default-to-current-branch behavior gives a clear context for invocation. However, no sibling is named as an explicit alternative (glab_ci_status exists and is the obvious shallow counterpart), so the guidance is strong but not fully prescriptive.

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