create_font_variant

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states the create action and the weight range, but does not reveal side effects, required permissions, return value, or validation behavior. This is a significant gap for a mutation tool without any structural safety signals.

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 concise, consisting of two short sentences. The first sentence states the core purpose, and the second clarifies weights. However, the weight information duplicates the schema's enum, so it is slightly redundant but not wasteful. Overall, it is well-structured and front-loaded.

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?

Given the tool has 6 required parameters, a nested data object, and no output schema, the description provides minimal context. It mentions requiring font data but does not explain the structure of the data object, the relationship between fontId and fontFamily, or what the API returns. It is adequate but leaves gaps for an agent to correctly invoke the tool without additional inference.

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 input schema descriptions cover all parameters (100% coverage), so the baseline is 3. The description's added statement 'Font weights: 100-900 in increments of 100' is actually inconsistent with the schema's enum, which includes 950. This contradicts the schema and provides no beneficial meaning beyond what the enum already offers, so the score is lowered to 2.

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 'Create a new font variant' uses a specific verb and resource, clearly distinguishing it from sibling tools like list_font_variants, update_font, delete_font, and delete_font_variant. It also adds a prerequisite ('requires font data'), making the purpose unambiguous.

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 by stating the prerequisite 'requires font data' and the accepted weight range. It implicitly tells the agent that to create a variant you need an existing font file. However, it does not explicitly exclude alternatives or state when not to use it, so it falls short of a 5.

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