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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: the specific validation rules, the error conditions (missing/empty/oversized/non-HTML), and the meaning of needsConfirmation and previewUrl. Only the semantics of confirmation handling could be slightly richer.

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?

The text is dense and front-loaded: purpose first, then return semantics, then error behavior, then next-step routing. The only mild redundancy is enumerating the return keys when an output schema already exists, though the explanation of needsConfirmation earns that space.

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?

With an output schema present, the description need not detail return fields, yet it still supplies the one non-obvious semantic (what needsConfirmation=true means) and the full follow-up workflow. Nothing an agent needs to call this correctly appears to be 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?

The single parameter has 0% schema description coverage and no enum, so the description should carry the meaning. It implies uploadId refers to a previously uploaded snapshot, but never states where the value comes from (presumably upload_design_snapshot) or its format. This is adequate given one trivial param but leaves a small gap.

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 precise verb ('Verifies') on a specific resource ('an uploaded design snapshot') and states the exact validation criteria (exists, non-empty, self-contained HTML, within size limit). It is clearly distinguishable from siblings like upload_design_snapshot and prepare_design_snapshot.

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 gives explicit downstream routing: after a successful check use propose_usability_test(uploadId) for a new test or relaunch_usability_test(projectId, uploadId) to re-test. It also names the failure path ('re-upload and check again'), so an agent knows exactly what to do in either branch.

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