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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is fully covered structurally. The description adds the local-rendering-only constraint and hints at output contents (licenses, script coverage), which is useful, but it is thin and never describes ordering, pagination, or how licenses/coverage are represented.

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 short sentences with the purpose front-loaded and no filler; the constraint and consumption note follow immediately. Nothing is padded or repeated.

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 zero-parameter, non-destructive list tool with no output schema, the definition covers what is returned and where the IDs are valid. A note distinguishing it from list_styles would close the remaining gap for correct sibling selection.

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 the baseline is 4 with nothing for the description to compensate for. The mention of font_id is a reference to how the returned value is consumed elsewhere rather than a parameter of this tool, which is clarified by 'local rendering overrides'.

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 — listing font IDs along with licenses and script coverage — so the agent knows exactly what data comes back. It does not, however, differentiate itself from the sibling list_styles, which an agent could easily confuse it with.

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 one concrete usage rule (the returned font_id is consumed by local rendering overrides) and one exclusion (not for cloud video rendering). That implies the right context, but it never states when to call this rather than list_styles or another sibling, and the 'no cloud video rendering' clause is telegraphic enough to be ambiguous.

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