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

Annotations already declare the mutation/idempotent/non-destructive profile, but the description adds real context beyond them: 'normal attachment screening' implies validation, 'preserving original assets, movie orders and expected project revision' discloses that existing media is untouched and that a revision check is enforced, and it explicitly rules out regeneration/replacement of the paid movie. It stops short of stating failure modes 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?

Two sentences, front-loaded with the action and then the constraint, with no filler. The second sentence carries a dense list ('original assets, movie orders and expected project revision') but each element is meaningful rather than padding.

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?

An output schema exists, so return values need not be described, and annotations cover the safety profile. What remains thin is parameter documentation for three required, opaque parameters on a mutation tool — operationId especially is left undefined, which is a meaningful gap for correct invocation.

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 0% and all three parameters are required, so the description carries the full burden. It only loosely gestures at expectedRevision via 'expected project revision' and never explains operationId (presumably the ID of the completed Motion operation) or projectId. An agent cannot tell what a valid operationId looks like or what happens on a revision mismatch.

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 and resource: 'Add the exact finished Motion result to project media.' This distinguishes it from generation/read siblings like studio_motion_create or studio_motion_result, though it never names those alternatives explicitly. The second sentence clarifies scope by negation ('does not replace or regenerate a paid movie').

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?

Usage is implied rather than stated: the phrase 'exact finished Motion result' and 'does not replace or regenerate' signal this is a post-generation attach step, not a creation step. However, no sibling is named and no explicit when-to-use/when-not-to-use condition is given, so the agent must infer the pipeline position.

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