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 value by confirming no creation/storage side effects and by sketching the shape of the returned design artifact, which goes 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?

Two sentences, front-loaded with the verb and resource before the enumerated return contents. The parenthetical/list detail is dense but each item is informative, so it earns its space; minimal trimming would be possible.

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 an output schema present the description need not detail return fields, yet it still summarizes them, and annotations carry the safety contract. For a two-parameter read tool this leaves nothing an agent needs missing.

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%, and both parameters (template id with example, format enum with default) are fully documented in the schema. The description only restates 'by its id and format' without adding format/default or id-resolution semantics, 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?

States a specific verb ('Return'), resource ('template from the HyperCodeMotion Studio gallery'), and lookup keys ('by its id and format'), then enumerates exactly what is returned (brief, scenes, composition, HTML docs, layers). The closing 'it does not create or store anything' cleanly separates it from the create_hcmotion sibling.

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?

Gives a clear when-to-use condition: 'Use it as the design reference when asked to follow a template', plus an explicit negative ('does not create or store anything'). It stops short of naming an alternative sibling (e.g. create_hcmotion) as the thing to reach for when you do want to create, so it is clear context without full routing.

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