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

Annotations already declare destructiveHint=true and idempotentHint=false, so safety is largely covered. The description adds one genuinely new behavioral detail beyond the annotations — that the sandbox is paused as a side effect — but says nothing about reversibility, resume path, or downstream effects on in-progress work.

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?

A single front-loaded sentence with zero filler. The primary action and its side effect are both stated immediately with no redundancy.

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 the rich annotations (destructive, non-idempotent) and the fully documented schema that carries the important decline-instead nuance, the description is nearly complete. A brief note that cancellation is not reversible/undoable would close the remaining gap.

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% and both parameters are described in the schema, including the const status value and the uuid format. The description adds no parameter-level meaning beyond the schema, so the 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?

"Cancel a running builder run and pause its sandbox" states a specific verb (cancel), a specific resource (builder run), and even a secondary effect (sandbox pause). It clearly distinguishes from the sibling getBuilderRun and resumeBuilderRun, though it doesn't name those alternatives explicitly.

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 description offers no when-to-use guidance, prerequisites, or alternatives. The useful scoping note ("review-pending changes must be declined instead") lives in the status schema property, not the description, so the description itself leaves routing entirely to inference.

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