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

Annotations already declare destructiveHint=true and the title says it mutates infra, so the safety profile is covered. The description reinforces this with 'MUTATING' and adds useful default behavior (empty body builds the latest commit on the linked branch), but says nothing about whether the build is queued asynchronously, what the response returns, or required permissions.

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 compact sentences with the mutating warning front-loaded, followed by the default and override behavior. The trailing REST path is mildly redundant but serves as an orienting detail rather than filler.

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?

For a trigger tool with no output schema, the description covers the default behavior and all optional targeting modes adequately, and annotations carry the destructive signal. It falls short on return-value expectations (e.g., a build id for later polling) and any required authorization context.

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 coverage is 100%, so the baseline is 3. The description goes slightly beyond the schema by framing sha/branch/pullRequestId as optional alternative targeting selectors and explaining that an empty body falls back to the linked branch's latest commit, which clarifies how the optional parameters interact.

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 and resource: 'start a new build for a build/combined service', and flags it as MUTATING up front. The action is clearly distinguishable from the sibling lifecycle tools (pause/restart/resume/scale), though no sibling is named explicitly for contrast.

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?

Usage is implied rather than stated: an agent can infer you call this to kick off a build. There is no guidance on when not to use it, no mention of checking existing builds via northflank_list_service_builds first, and no prerequisites or permission notes.

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