Check whether a proposed company name is available (IM only)

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the tool is safe and idempotent. The description adds valuable behavioral detail beyond annotations: it explains the return format (query, available, warning, similar_names[]), the precise logic for available=true (both conditions must be met), and the structure of similar_names rows. It also notes pricing (free) and no-auth requirement. Loses a point because it doesn't mention potential upstream response delays or rate limiting.

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 core purpose. It could be slightly more concise (e.g., remove 'Pricing: free; no login required' as it's not critical), but overall efficient and well-structured.

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's complexity (5 params, output schema present), the description is complete enough. It explains the return format, availability logic, and jurisdiction restriction. The output schema exists, so return fields are fully documented there. Could improve by mentioning edge cases (e.g., empty company_name), but otherwise solid.

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 description coverage is 100%, so baseline is 3. The description adds value by explaining the overall return structure and availability logic, which helps understand parameters like company_name and sort_by in context. However, it doesn't directly add per-parameter meaning beyond the schema, so a 4 is appropriate.

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 explicitly states the tool checks company name availability via the Isle of Man Companies Registry endpoint. It clearly specifies the verb 'Probe', resource 'Check Name Availability endpoint', and distinguishes from sibling tools like search_companies (which searches existing companies) and about (which provides server info).

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 specifies that the tool is for Isle of Man (IM) only, notes that other jurisdictions return 501 (explicit when-not-to-use), and mentions no login required (accessibility). It also clarifies the exact conditions for availability (no specific warning and empty similar-names table), guiding the agent when to use this free probe.

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