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

Annotations already declare readOnlyHint and openWorldHint, but the description adds genuinely non-structured context: cost of $0.002 USDC per successful call via x402 on Base/Solana/Arc, and that failed calls are not charged. That payment/charging behavior is critical for an agent and appears nowhere in annotations or schema.

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 sentences plus a pricing sentence, all front-loaded with the core operation first and the pricing/billing caveat last. No filler, though the pricing clause could be tightened slightly.

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?

An output schema and annotations exist, and schema coverage is 100%, so the description does not need to explain return fields; it still summarizes them briefly. Combined with scope limits and payment terms, this is nearly complete, lacking only explicit routing to sibling tools for case determination.

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 100%, so both parameters (q, limit) are already documented with types, ranges and examples (EAR99, 5A992). The description adds only the generic notion of a search term, not syntax guidance or edge cases 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?

States a specific verb and resource: searching the US EAR (15 CFR) text on eCFR for a term like EAR99 or an ECCN, returning matching sections with excerpt, part and section. The scope-limiting sentence ('shows regulatory text hits only; does not decide the ECCN or licence requirement') further defines the operation. It does not name a sibling tool, so 5 is not warranted.

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 says what the tool will NOT do ('does not decide the ECCN or licence requirement for a product'), which carves it apart from classification tools like hs_code_classifier or us_cbp_cross_rulings without naming them. Clear usage context for a text-lookup use case, but no explicit alternative is named for agents that actually need a determination.

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