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

The annotations provide only readOnlyHint=false, openWorldHint=false, and destructiveHint=falseaborate. The description adds valuable behavior beyond that: after an in-progress update, the preview still shows the previous design, and the URL can expire or return 401. It does not mention auth prerequisites or side effects, so it stops short of a 5.

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?

Three concise sentences front-load the core purpose, then cover the stale-snapshot caveatchen, then give routing guidance. Every sentence contributes distinct information with no 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?

Given the low complexity (one required parameter) and the presence of an output schema, the description covers purpose, usage timing, a stale-state caveat, and the preferred alternative. Nothing needed for correct selection or invocation 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 coverage is 0% and the description does not explain job_id directly. However, the phrase 'a job's current snapshot' supplies enough context to infer that job_id identifies the job whose preview is being refreshed. For a single simple required string parameter, this is adequate but not rich.

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 uses a specific verb and resource ('Mint a fresh viewer_url') and ties it to a job's current snapshot. It is clearly distinguishable from sibling tools like check_run or export_design because it names the artifact produced and the condition it addresses.

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?

It explicitly says when to use this tool ('Use this when a completed preview link expired or 401s') and when to prefer a sibling instead ('Prefer check_run on the new run_id and only share that viewer_url when status is completed'). This gives an agent precise routing guidance.

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