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

Annotations only declare readOnlyHint=true, so the description adds meaningful behavioral context: it reads a canonical registry, never exposes WIP or relationship-only records on public calls, and requires no payment. These details go beyond the safety hint and help the agent anticipate response boundaries.

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 compact, front-loaded with the core listing purpose, and each sentence carries useful guidance. Minor redundancy exists between 'Free geography utility' and 'No payment required,' but the overall structure remains efficient and readable.

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?

With no output schema, the description compensates by enumerating key return fields (row counts, vintages, target levels, source license metadata) and stating what is not exposed. It also gives clear first-step guidance. It could elaborate on pagination or response shape, but for a list/discovery tool with zero required parameters, it is sufficiently complete.

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?

Schema coverage is 100%, so the baseline is 3, but the description adds practical guidance beyond the schema by saying 'Pass country_scope whenever the country is known' and clarifying that public calls never expose WIP. This gives the agent extra decision-making context for parameter use.

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 ('lists') and a concrete resource ('published, callable geographic reference systems' from the 'canonical crosswalk registry'), and names the exact metadata fields returned. It also frames the tool as the discovery entry point for loc_id exchange capabilities, which separates it from sibling resolve/convert tools without needing to inspect their schemas.

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 tells the agent to 'Call this first' when learning whether identifiers can be exchanged, and instructs to 'Pass country_scope whenever the country is known.' It does not name alternative tools or state when not to use the tool, so it stops short of full exclusion guidance.

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