tool_check_visa_requirement

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

Despite no annotations, the description discloses key behaviors: read-only, no auth required, data source (static snapshot), return fields, error handling for invalid codes, and a caveat to verify with embassy. This fully compensates for missing annotations.

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 about 100 words, well-structured with clear sections, bullet points for return fields, and uses bold for tool names. It is front-loaded and every sentence adds value.

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 no output schema, the description lists all return fields (category, apply_link, cost, processing time, guidance notes) and error handling. It is complete for a simple visa check tool and appropriately references relevant siblings.

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 0% but the description provides a detailed Args section for both parameters, including ISO codes and examples (e.g., 'US', 'GB', 'JP'). This adds significant meaning beyond the minimal schema titles and types.

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 'Check the visa requirement for one passport entering one destination country.' It uses a specific verb ('Check') and resource ('visa requirement'), and distinguishes itself from siblings like 'tool_visa_free_destinations' and 'tool_check_transit_visa'.

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?

Explicitly states when to use this tool ('single passport-destination pair') and when to use alternatives ('tool_visa_free_destinations' for listing all countries, 'tool_check_transit_visa' for transit visas). Also includes read-only and no-auth prerequisites.

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