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

With no annotations provided, the description carries full behavioral disclosure. It labels the tool as 'EXPERIMENTAL,' notes 'No API key required,' and explains the behavior of searches with unregistered jurisdictions (empty 'completed' results) and the `XX` (GLEIF LEI) global fallback. This is thorough and goes beyond the typical surface-level description.

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 front-loaded with a one-line purpose and 'EXPERIMENTAL' warning, then provides necessary context about jurisdiction codes and fallback behavior, ending with an example. Every sentence serves a distinct purpose, and the structure is clean and easy to scan.

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?

Given the tool has zero parameters and an output schema exists, the description doesn't need to detail return fields. It covers purpose, usage context, behavioral caveats, and authentication requirements, making it complete for an agent to understand when and how to use the tool.

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, and the input schema is empty. The example `company_registries()` makes the lack of arguments unambiguous, and the description's mention that it lists registries with no input requirements adds crystal-clear semantics.

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 'List available company registries and supported jurisdictions' with a specific verb and resource. It further distinguishes itself from sibling tools by explaining that it provides the authoritative list of jurisdiction codes for company_search_person and company_search_company, and that it outranks those tools' descriptions.

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 when to use this tool: to obtain the LIVE list of registry codes before using company search tools. It also explains that the returned codes take precedence over those in sibling tool descriptions and warns that unsupported country codes will return empty 'completed' results, preventing misinterpretation.

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