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

With no annotations provided, the description carries the full burden, and it delivers: it states the return shape, the sources returned, filtering semantics, default and max limits, and even notes that selected families will Just Work in later calls. No side effects or hidden behaviors are claimed.

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?

Three dense sentences, each earning its place: scope, return shape/filtering, and downstream compatibility. The key purpose is front-loaded, and the details are organized without wasted words.

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 read-only discovery tool with no output schema, it is unusually complete: it documents the returned object structure, sources, pagination cap, filters, and the reason to call it. An agent has enough context 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 coverage is 100%, so the baseline applies. The description restates q, source, and limit semantics that are already in the schema, adding little new parameter-level meaning. It usefully ties results to future font_family usage, but it doesn't deepen understanding of current parameters.

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 opens with a specific verb and resource: 'List available font families' and enumerates every source, including custom uploads. It also explicitly frames the tool as the discovery step before set_layer_text / add_text_layer, which makes its purpose immediately distinguishable from the large sibling list.

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 when-to-use instruction: 'Use this to discover families before set_layer_text / add_text_layer when you don't know what to pick.' It also explains the q/source/limit filtering behavior, so an agent knows exactly how to narrow results.

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