design_preview_at

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

With no annotations, the description carries the full disclosure burden. It says the tool sets a current time and returns it, but does not say whether the change is transient (scrub state only) or persistent, whether it affects export/render, or what the 'format' parameter actually does — the schema lists an image format hint that the description never reconciles with 'returns the time that was set.'

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 short, front-loaded sentences with no filler. The brevity is appropriate, though the second sentence about the return value is arguably the least valuable information given the first sentence already implies it.

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 state-mutating editor tool with no annotations and no output schema, the description is silent on scope (which animation/preview), side effects, and the role of the 'format' parameter. An agent would need to guess at several behaviors before calling safely.

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 both 'time' (in seconds) and the 'format' enum are already documented. The description adds no parameter-level meaning beyond restating the return, 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?

The description states a specific verb and resource ('Set the current animation time for preview') and clarifies the return value. It is clear what the tool does, though it does not distinguish itself from nearby timeline/animation siblings such as design_set_keyframe or design_create_timeline.

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?

There is no explicit guidance on when to call this versus alternatives, and no stated prerequisites (e.g., whether a timeline must exist first, or whether this is meant for scrubbing before capture). The word 'preview' implies context, but nothing tells an agent when or when not to use it.

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