Variables and modes

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

Beyond the readOnlyHint annotation, the description discloses important behavior: aliases are resolved only when the target is in the same file, external variables become opaque assetRefs, and values are formatted per type (hex, verbatim strings/numbers). This gives an agent meaningful expectations about output and cross-file behavior.

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 compact and front-loaded with the core purpose, then expands into output semantics and filters. Every sentence carries necessary information; there is no filler or repetition of schema details.

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 read-only retrieval tool with rich annotations and fully described parameters, the description covers the essential semantics: what is listed, how values are represented, how aliases are handled, and how to filter. The lack of an output schema is compensated by the detailed return-value explanation in the description.

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 coverage is 100%, so the baseline is 3. The description adds value by explaining that 'set' accepts a collection name or guid and that 'query' is a case-insensitive substring match, which clarifies the two primary filtering parameters beyond the schema descriptions.

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: 'List the design tokens in the file' and precisely enumerates what is returned (variable collections, modes, per-mode values, aliases, assetRefs). This clearly distinguishes it from sibling tools like fig_style or fig_components by focusing on variables and tokens.

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 gives clear context on what the tool returns and how to narrow results via 'set' and 'query'. It does not explicitly name sibling tools or say when not to use it, but the purpose and filtering instructions make the intended usage unmistakable.

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