get_font_family_info

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 makes clear this is a read-only lookup and specifies the exact data sources: the user's machine and Google Fonts. It does not describe error behavior or return format, but those are minor for this simple lookup.

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?

Two sentences deliver the core purpose, scope, and data sources with no wasted wording. The main outcome is front-loaded, and the supporting detail about lookup sources is placed efficiently in the second sentence.

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?

This is a simple one-parameter, side-effect-free lookup, and the description is nearly complete: it states what information is returned, where it is looked up, and what input is needed. The main omission is a detailed response shape, but there is no output schema and the domain is straightforward enough that the description is sufficient for tool selection and invocation.

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 description coverage is 100% and the single 'familyNames' parameter is already clearly documented as an array of font family names. The tool description adds no additional parameter nuance beyond what the schema provides, so 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 a specific action ('get information'), a specific resource (font family), and the outcomes: availability plus all weights and styles. It also adds the two lookup sources, local machine and Google Fonts, which distinguishes it from generic info-gathering siblings like get_basic_info or get_node_info.

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 tool is useful when font family availability or weight/style details are needed, and it provides context about where fonts are searched. However, it does not explicitly state when to prefer this tool over alternatives, nor does it mention exclusions, prerequisites, or fallback behavior.

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