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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: the return behavior is conditional — it emits Remotion commands plus a checklist, and only renders actual images on a connection running on the user's machine. That dual-mode behavior is not derivable from any structured field.

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, no filler, and the primary capability is front-loaded before the conditional rendering detail. Slightly dense in the second sentence, where two distinct modes are compressed together, but nothing is wasted.

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 no output schema, the description carries the burden of describing returns and does so (commands, checklist, images). For a six-parameter tool with a nested props object it is largely sufficient, though the ambiguity about exactly what comes back in each connection mode leaves a small gap.

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 all six parameters (entry, props, scale, frames, projectDir, composition) are already documented in the schema, including the non-obvious guidance on picking first/settled/last frames and keeping scale small. The description adds nothing parameter-level, 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?

Specific verb and resource: renders chosen frames of a Remotion composition as images, and names the concrete artifacts returned (Remotion commands plus a review checklist). It is clearly distinguishable from plan-video and the design-system siblings. It stops short of naming any sibling it could be confused with, but the action is unambiguous.

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 description never says when to reach for this tool versus plan-video (the obvious adjacent sibling) or when not to. The only situational cue is an implicit review workflow ('a checklist for reviewing them'), which the agent must infer. No prerequisites or preconditions are stated.

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