list_fonts

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

With no annotations, the description carries the full burden. It conveys that this is a non-mutating enumeration of 'registered' fonts, which sets a safe expectation, but says nothing about ordering, whether it includes unregistered/unavailable fonts, or rate/size limits for the returned list.

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?

A single front-loaded sentence with no filler or redundancy. Every word contributes to identifying the resource and its scope.

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 list tool with no output schema and no annotations, the description is nearly sufficient: the implied return is a set of font names usable in .manim files. It could be strengthened by stating the return shape (names as strings) or whether the list is environment-dependent, but nothing critical is missing.

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 schema has nothing to document; the baseline of 4 applies. The description correctly signals the no-argument, enumerate-all nature of the call, leaving no parameter ambiguity.

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 (registered font names) plus scope (available for use in .manim files). The resource is clearly distinct from siblings like list_atlases and list_screens, though it never names those siblings explicitly.

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?

The phrase 'available for use in .manim files' implies the context in which the result matters, but there is no explicit when-to-use guidance, no prerequisites, and no pointer to an alternative way of discovering fonts.

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