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

With no annotations, the description carries the burden of transparency. It clearly indicates a read-only listing operation ('List all available'), enumerates the category domains, and discloses that the return value is niche IDs. It does not discuss pagination or auth, but for a zero-parameter list tool this is adequate.

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 three sentences, front-loaded with the primary action and scope. The list of example categories is useful context, and there is no redundant or filler content.

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 simple zero-parameter tool with no output schema, the description sufficiently covers purpose, what it returns, and how it fits into the broader workflow ('needed for all other tools'). No significant gaps remain.

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, with a schema coverage of 100% (empty properties). The description adds value by explaining what the output represents (niche IDs needed for other tools), which satisfies the baseline for parameter-less tools.

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 uses a specific verb ('List') and names a clear resource ('all available service directories in the LocalPro network'). It also explains that the result is categories of verified providers and references the needed niche IDs, distinguishing it from sibling tools like list_cities or search_providers.

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 frames the tool as the 'starting point' and states that it returns 'niche IDs needed for all other tools', giving clear guidance on when to use it. It does not explicitly list alternatives or when not to use it, but the priority context is strong.

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