fonts_list

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

With readOnlyHint=true already covering the safety profile, the description still adds two real traits: results come from a 'bounded cache' (so the list may be incomplete or stale) and font file paths are deliberately withheld. However, it never explains the refresh parameter's behavior (e.g. whether it bypasses the cache), which is the one behavioral detail a caller most needs.

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?

One front-loaded sentence with no filler; the resource and the two key constraints (bounded, no file paths) all land immediately.

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?

An output schema exists, so return values need no explanation, and the read-only annotation covers safety. Still, for a tool whose only parameter is an undocumented cache-bypass flag, the description leaves a real gap in how to invoke it correctly.

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 0% and the single parameter 'refresh' is completely undocumented in both schema and description. The phrase 'bounded cache' hints that a cache exists but the description does not connect it to the refresh flag or explain its default effect, so it fails to compensate for the coverage gap.

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 names a specific verb and resource ('Lists ... local system font family names') and scopes it precisely with 'local system' and 'family names' rather than full font data. It does not explicitly distinguish itself from the sibling fonts_preflight, so an agent must infer the split between listing fonts and preflighting them.

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?

There is no when-to-use guidance, no mention of the fonts_preflight alternative, and no indication of when a caller should prefer this over inspecting or validating fonts. The purpose is inferable but no routing guidance is provided.

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