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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description goes beyond them by disclosing the cost and payment mechanism ('Paid ($0.001, x402)') and the return payload ('with source document and license'), which the agent needs before calling. It stops short of describing pagination or result caps beyond what the limit parameter implies.

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?

Two compact sentences with no filler. The heavy filter list makes the first sentence slightly run-on, and the critical payment caveat is deferred to the end rather than front-loaded, but overall it is efficient.

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 paid, read-only 7-parameter lookup with no output schema, the description covers cost, filters, and returned fields, which is most of what is needed. It omits the crucial routing information relative to sibling search_specs and says nothing about result pagination, leaving a gap for an agent choosing between spec-retrieval tools.

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%, and the schema spells out examples and constraints for max, min, unit, family, quantity, etc. The description only loosely maps to the quantity/family/unit/range parameters without adding syntax or precision beyond the schema, so the baseline 3 applies.

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 identifies the resource (a structured specification table) and enumerates the filter dimensions (quantity, unit family, unit, value range) plus the payload it returns (source document and license). However, it never differentiates this tool from the sibling search_specs, so an agent cannot tell which one to select from the description alone.

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?

There is no when-to-use guidance, no exclusions, and no mention of the obvious alternative search_specs. The agent must infer usage purely from the name and filter list.

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