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

With no annotations provided, the description carries the full burden. It transparently states that it lists all domains with counts, clarifies there are no parameters, and shows an example invocation. For a read-only list operation, this is sufficient, though it does not mention explicit return format or side effects.

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 concise and well-structured: it leads with the core function, then provides usage context, then parameter clarity, and ends with an example. Every sentence adds value without redundancy or filler.

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 parameterless list tool with no output schema, the description is complete: it specifies the output content (domains and counts), when to use it, and how to invoke it. It also references the next logical step, making the surrounding context fully covered.

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, so the schema coverage is 100% trivially. The description reinforces this with 'No parameters required' and a call example, meeting the 0-parameter baseline of 4 and adding practical clarity.

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 verb 'List' and the resource 'SDM domains', adding 'count of data models in each' for specificity. It also distinguishes from the sibling 'list_models_by_domain' by positioning itself as the entry point, making its unique role clear.

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 explicitly says 'Use this as the entry point when the user wants an overview' and 'before calling list_models_by_domain', providing concrete when-to-use guidance and naming the relevant alternative. This meets the 'explicit when/alternatives' criteria.

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