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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It says 'Cancel' but does not state whether cancellation is reversible, what happens to partial build artifacts, whether it errors on a finished session, or what permissions are required — significant gaps for a mutation tool.

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?

One short, front-loaded sentence with no filler — the verb and object lead immediately. It is efficient, though the extreme brevity leaves the substance thin rather than merely tight.

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 mutation tool with no annotations, no output schema, and an undocumented required parameter, the description is too thin. It omits prerequisites, the source of the session ID, error behavior, and the result of a successful cancellation.

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?

The single parameter sessionId has 0% schema description coverage, so the description must compensate and does not. It never explains what a session ID is, where the agent obtains one (e.g. from codebase_start_build or codebase_get_build_status), or the expected format.

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?

The description names a specific verb ('Cancel') and resource ('an active Codebase build session'), which cleanly separates it from siblings such as codebase_start_build and codebase_rollback_deploy. It is clear on its own, but it never explicitly names the sibling it complements or the counterpart it undoes.

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?

The word 'active' implies the tool applies only to in-flight builds, which is a usable hint. However, there is no explicit when-to-use guidance, no statement of what to do for a queued or already-completed build, and no reference to any alternative tool.

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