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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds genuinely useful detail beyond them: it discloses that word overrides are preserved by default and only cleared when clearWordOverrides=true, and that existing captions are restyled while spoken audio is preserved. That explains exactly what the 'destructive' behavior touches, though it says nothing about permissions or auth requirements.

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 short sentences, front-loaded with the core action, then the override caveat, then the preservation guarantee. No filler and every sentence carries distinct information.

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, return values need not be explained, and the description covers the mutation's effects and preservation guarantees adequately for a destructive tool. It is still thin on permission/authorization context and on how the required idempotencyKey should be supplied.

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 only 40%, so the description must compensate, and it does explain the semantics of clearWordOverrides (the flag that controls override destruction). However, projectId, lookId, workspaceId, and idempotencyKey receive no added meaning in the description, leaving most parameters undocumented.

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 ('Apply') and resource ('a verified caption look') with an explicit scope of 'one project', so the action is unambiguous. It does not explicitly differentiate itself from adjacent caption siblings like captions_themes_list or captions_source_prepare, which is the only thing keeping it from a 5.

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 'verified' implies a prerequisite that the look must first be validated, giving some implied usage context, but there is no explicit when-to-use, when-not-to-use, or named alternative. The agent has to infer the workflow ordering.

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