check_font_loading

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

With no annotations, the description carries full burden. It indicates a read-only verification and mentions output fields, but does not disclose what happens if fonts fail to load, or the format of the status field. For a simple check tool, this is adequate but not fully transparent.

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 two sentences with no fluff. The first sentence states the purpose, the second lists return fields. It is front-loaded and every word earns its place.

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 simple check tool with no output schema, the description covers the basic purpose and output fields. However, it lacks details like the format of the returned data (array or object), the meaning of 'status', and any prerequisites (e.g., fonts must be requested). It is minimally complete but could be more informative.

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% with both parameters (tabId, apiKey) described. The description adds no extra parameter meaning beyond the schema, so baseline 3 is appropriate. The description does not repeat or enhance parameter semantics.

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 verifies web font loading and lists the return fields (family, status, weight, style). This distinguishes it from sibling check tools like assert_css_property or check_color_contrast, which focus on other aspects. However, it could be more explicit about the context (e.g., active tab) even though tabId parameter implies it.

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?

No guidance is provided on when to use this tool versus alternatives. Among many sibling check tools, an agent could benefit from hints such as 'Use this after page load to verify fonts, not for checking specific CSS properties.' The description only states what it does, leaving the agent to infer usage context.

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