Describe font file

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

With no annotations, the description carries the burden of behavioral transparency. It states that the tool 'reads' (implying non-mutating) and that it reports what the font 'declares about itself,' which clarifies it only examines metadata, not the actual glyphs or rendering. It also adds context that the input is a standalone file, not a document. It doesn't discuss error handling or edge cases, but for a simple read operation, this is adequate.

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 a single, front-loaded sentence that immediately states the action ('Reads'), the resource (standalone .ttf/.otf), and the output (family/bold/italic triple). Every word adds value, with no filler or repetition. It is a model of conciseness.

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's low complexity (one parameter, no output schema), the description is sufficient: it explains the purpose, the input type, and the output. It does not explicitly mention when to use it versus alternatives, but for a simple read-only tool, the description is complete enough for an agent to select and invoke it correctly. The 'not a document' note helps prevent misuse.

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 has 100% coverage for the single parameter 'source', including a clear description and detailed union alternatives (path or bytesBase64). The tool description does not add additional semantic meaning beyond what the schema already provides. Therefore, the baseline score of 3 is appropriate.

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 purpose: it reads a standalone TrueType/OpenType font file and reports the family/bold/italic triple it declares. This is a specific verb and resource, and specifying the output distinguishes it from sibling tools like 'fonts' or 'pdf_inspect' which may handle fonts in other contexts.

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 implies the use case: when you have a standalone .ttf/.otf file and need its declared metadata. It emphasizes 'standalone' and 'not a document,' but does not explicitly mention alternatives or when not to use this tool. While the context is fairly clear, the lack of explicit comparison to sibling tools leaves this at the 'implied usage' level.

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