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

The annotations already disclose that this is a read-only, idempotent, non-destructive, closed-world operation. The description adds useful scope by clarifying that only places with opioid treatment providers are returned, but it does not describe ordering, return structure, or pagination behavior.

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 a single, front-loaded sentence with no wasted language. It states the resource and the key filtering condition immediately.

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, no-parameter, read-only list tool with strong annotations, the description is largely complete. It tells the agent what is returned at a high level, though it could be slightly richer by noting whether the result is hierarchical or flat.

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?

This tool has zero parameters, so parameter semantics are not a meaningful burden. The baseline for a no-parameter tool is 4, and there is no parameter information that the description needs to compensate for.

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,' with a well-defined resource: countries, regions, and cities that have opioid treatment providers. It clearly distinguishes the tool's subject matter from siblings like list_categories and list_sources, though it does not explicitly name alternatives for disambiguation.

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 intended use is implied by the description: retrieve geographic locations that have providers. However, there is no explicit guidance on when to choose this over search_listings or other sibling tools, and no stated exclusions or prerequisites.

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