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

The description says 'List the component registry' which clearly implies a read-only operation, but the annotations declare destructiveHint: true. This is a direct contradiction – the description does not disclose any destructive behavior and instead suggests a non-mutating action. No additional behavioral context is provided beyond this contradiction.

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 two sentences long and packs relevant information: the resource being listed, the types of templates, the content of each entry, and a pointer to the next step. It is slightly verbose with the parenthetical list of template types, but this is informative and aids clarity.

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?

The description explains the output format (ports, params, discipline notes) and how to proceed after listing (compose with sim_compose). It is complete for a listing tool with no parameters and no output schema. However, the contradiction with the destructiveHint annotation introduces confusion about whether the tool has side effects, which detracts from completeness.

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?

There are zero parameters, and the schema coverage is 100% (since no params exist). The description adds value by explaining what the registry entries contain (ports, params, discipline notes), which helps the agent understand the output structure. Since there are no parameters to document, the description correctly avoids parameter details.

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 clearly states the tool's purpose: 'List the component registry' with a specific verb and resource. It enumerates the template types and explains what each entry contains, making it easy to distinguish from other sim_* tools. The mention of sim_compose further differentiates it as a discovery tool rather than a composition 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?

The description provides a clear usage hint by stating 'Compose them with sim_compose', indicating the typical workflow of listing then composing. It does not explicitly list when not to use this tool, but the context strongly implies it is for browsing available templates before composition.

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