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

With no annotations, the description carries full behavioral burden. It states it's a real-time worldwide lookup, notes pricing ($0.01 via x402 payment), and indicates read-only nature. Missing rate limits, authentication requirements, and error handling, but adequately describes core behavior.

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 relatively concise and front-loaded with the primary action and return data. It includes useful extras like pricing and use cases without excessive verbosity, though the contradictory input statement adds unnecessary confusion.

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 one parameter with full schema coverage and no output schema, the description should be self-sufficient. It covers purpose and usage but fails on input accuracy (contradiction) and does not address error cases (e.g., invalid LEI). This limits agent reliability.

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 description claims 'LEI code or legal name' as input, but the schema requires a strict 20-character LEI pattern. This contradicts the schema and misleads the agent about valid inputs. Additionally, schema coverage is 100%, so no param info beyond schema is needed, but the misleading statement severely harms usefulness.

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 the tool's purpose: looking up Legal Entity Identifiers via the GLEIF registry, listing return fields (legal name, status, jurisdiction, etc.) and use cases (regulatory reporting, KYB). It does not explicitly differentiate from sibling tools, but the specificity is sufficient for a distinct purpose.

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 provides context for when to use (regulatory reporting, counterparty agents) and input format ('LEI code or legal name'). However, it does not specify when not to use or offer alternatives, leaving the agent without exclusion guidance.

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