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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: it is a bootstrap/discovery call that returns definitions rather than performing work, and it discloses that motion_compile requires the CLI or a hosted key.

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?

Front-loaded with what is returned, then the call order, then the compile caveat. The trailing promotional URLs (motion-check, pricing) are useful pointers but slightly dilute the definition; the substance is still tight and well ordered.

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 compensates by enumerating the return contents (names, purpose, schemas, defaults) and the authoring rules. Combined with the sequencing guidance and the compile auth caveat, an agent has everything needed to use it correctly in the workflow.

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 takes zero parameters, so there is nothing for the description to document and the baseline of 4 applies. The description correctly implies no input is needed to retrieve the catalog.

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 (returns) and resource (the catalog of verified motion primitives) and enumerates the payload (names, purpose, parameter schemas, defaults) plus the authoring rules for a MotionSpec. It also implicitly distinguishes itself from siblings by naming motion_validate and motion_compile as downstream steps.

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 an explicit sequencing instruction ('Call this FIRST, then write the spec yourself and validate it with motion_validate') and clarifies where motion_compile actually runs (CLI or hosted endpoint with a key). An agent knows both when to call it and which sibling to use next.

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