list_fonts

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

Annotations already cover the safe-read profile (readOnlyHint, idempotentHint, destructiveHint false), so the bar is low. The description adds useful context beyond them: fonts are bundled and intended for local rendering, and the IDs are meant to be consumed by other tools. It doesn't note any availability constraints, which is the only gap.

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 with zero filler; the resource and its payload are front-loaded and the follow-up action is second. Every sentence 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?

With an output schema present, return values needn't be spelled out, and with no input parameters there is nothing else to document. The description supplies the remaining needed context: what the IDs are for and where to use them next.

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 tool takes zero parameters, so per the baseline a 4 applies. The description's only parameter-like content refers to other tools' overrides argument, not its own, which is appropriate rather than redundant.

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?

States a specific verb (List) and resource (bundled named fonts) and enumerates the returned attributes (IDs, licenses, script coverage), which distinguishes it from the sibling list_styles. An agent can tell at a glance this is the font-inventory tool.

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?

It gives an explicit downstream usage path: feed a font_id as overrides to preview_style or caption_video. It does not state when not to use it or name a conflicting alternative, but for a zero-param discovery tool the routing guidance is clear.

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