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

The annotations already establish that this is a non-destructive, idempotent mutation; the description adds useful operational context by stating the READY/ownership constraint and that the call is free. It does not describe error cases or return behavior, but it adds meaningful context beyond the annotations.

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?

The description is short and front-loaded: purpose first, downstream relevance second, eligibility and cost last. Every sentence carries useful information without repetition.

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 simple selection/mutation tool, the description covers purpose, prerequisites, downstream effect, and cost, while the schema documents the optional assetId behavior. The main remaining gap is the lack of explicit seriesId explanation and any return-value expectation, but the definition is otherwise sufficient to call correctly.

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?

The description clarifies the relationship between series and sheet and notes that sheetId corresponds to character_id for motion-clip generation. However, with only 67% schema description coverage, the required seriesId parameter remains undocumented in both schema and description, so the compensation is partial.

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: choose which character sheet a series uses and which image is its main one. It also ties the operation to autoshort_generate_motion_clip, so the agent can distinguish this selection tool from generation and sheet-fetching siblings.

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 clear usage context: the chosen main image is what generate_motion_clip starts from when character_id is passed, and only the caller's own READY sheets/images can be selected. It does not name a direct alternative tool, but the prerequisites and downstream dependency are explicit.

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