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

Annotations already mark the operation as non-read-only and non-destructive, and the description adds valuable behavioral context: 'this changes nothing until the clip is generated again' and that guidance can be set or cleared. It doesn't mention response shape or auth, but for this simple update the deferred-effect disclosure is the most important behavioral trait and it is present.

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?

Two sentences with no filler; the main action is front-loaded, the prerequisite is stated, and the deferred side effect earns its place. Nothing in the description is redundant with the schema.

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 three-parameter, fully schema-covered update tool, the description plus schema provide enough to invoke it correctly: what it does, how to get the asset id, and the key behavioral consequence. The only minor gap is not describing what happens if the asset_id doesn't belong to the shot, but that's a validation concern rather than a core invocation requirement.

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 description coverage is 100%, so the schema already explains all three parameters, including that guidance can be null/empty to clear. The description adds the workflow hint that asset_id comes from list_shot_continuity_references, but it doesn't meaningfully go beyond what the schema already states.

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 states a specific action, 'Set or clear the guidance on one continuity reference already attached to a shot', with a clear subject and scope. The phrase 'already attached' distinguishes it from attaching, listing, or removing references, so an agent can select it correctly even among many sibling tools.

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 an explicit prerequisite workflow: list references first with list_shot_continuity_references to get the asset id, which is genuinely useful guidance. It clearly implies the tool is only for existing references, but it doesn't explicitly name attach or remove as alternatives for other cases, so it stops short of full when/when-not guidance.

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