lei_lookup

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

Annotations declare readOnly and idempotent. Description adds failure conditions (invalid format, LEI not found) and suggests retry strategies, providing behavioral context beyond 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?

Extremely concise: 4 sentences that front-load purpose, then provide usage instructions and failure modes. No redundant information.

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 lookup tool with one parameter and clear annotations, the description covers purpose, usage alternatives, and failure recovery comprehensively.

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 covers the sole parameter entirely (100% coverage) with pattern, examples, and length constraints. Description adds no additional semantic value for the parameter, so baseline score of 3 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?

Description clearly states 'Get full details for a specific LEI code' and lists specific data fields (legal name, address, jurisdiction, status, etc.). It distinguishes from siblings like validate_lei and batch_lei_lookup.

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 provides 'USE WHEN' examples and 'FAILS WHEN' conditions, including format validation and database lookup failure. Alternatives like validate_lei, batch_lei_lookup, and search_entity are named.

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