Listar engines

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

With no annotations, the description carries the full burden of behavioral disclosure. It only states a noun phrase, giving no information about whether the operation is read-only, the output format, or any side effects. The agent cannot infer safety or return structure from the description.

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?

The description is extremely concise, using only four words. It is front-loaded and wastes no words, but it is so sparse that it sacrifices clarity. Still, for a tool with no parameters and a simple purpose, the brevity is acceptable.

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?

Given the tool's low complexity (zero parameters, no output schema), the description is minimally viable. However, it does not explain what the returned data will look like (e.g., a list of engine names and a URL) or any context on how to use the results with the sibling tool. Some gaps remain, but the purpose is clear enough for a simple list operation.

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 has zero parameters, and the schema fully covers the input (empty object). According to the guidelines, a baseline of 4 is appropriate for no-parameter tools. The description adds no parameter semantics, but none are needed.

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 'Engines soportados y URL de Kroki' clearly identifies the resource as supported engines and the Kroki URL, and the tool name 'list_engines' explicitly indicates the action. It distinguishes itself from the sibling tool 'render_diagram' by focusing on engine discovery rather than rendering.

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 description provides no guidance on when to use this tool versus the sibling 'render_diagram'. Usage context is only implied by the tool name and the fact that rendering requires knowing available engines, but no explicit when-to-use or alternatives are mentioned.

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