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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the description's claim of 'returns the catalog' is consistent and adds no contradiction. The description provides extra context such as free check links and pricing for the hosted endpoint, which is useful for the agent to understand external dependencies. Since the read-only behavior is already covered by annotations, the extra content is a positive addition, though not strictly behavioral.

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 front-loaded with the core purpose in the first sentence, followed by ordering guidance and external links. It is three sentences and relatively efficient; the pricing link and 'free motion check' are somewhat tangential to the tool's invocation but still useful context. The structure is clean and not overly verbose, so a 4 is appropriate.

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 full burden of explaining the result content. It clearly states that the catalog includes names, purpose, parameter schemas, and defaults, plus authoring rules. It also gives order-of-use and validation guidance, which is essential for the agent. The description is sufficient for an agent to know what to expect and how to use the tool first.

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 tool has zero parameters, so the description adds no parameter-specific semantics. With schema coverage at 100% (vacuously), the baseline for zero parameters is 4, and no additional parameter explanation is needed. The description's mention of 'parameter schemas' in the catalog result is context, not parameter documentation.

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 clearly states the tool's function: returning a catalog of motion primitives with names, purpose, parameter schemas, defaults, and authoring rules. It explicitly names motion_validate as the validation step, providing some sibling differentiation. However, it does not contrast with motion_audit, motion_stats, or motion_compile, relying mostly on their distinct names and the 'call this FIRST' instruction to distinguish them.

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 explicitly instructs 'Call this FIRST, then write the spec yourself and validate it with motion_validate,' giving very clear ordering and next steps. It also indicates that motion_compile requires a CLI or a hosted endpoint key, which informs the agent about downstream usage requirements. It does not contain any when-not-to-use conditions or alternatives beyond the one sibling mentioned, but the overall guidance is effective.

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