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

The annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely non-derivable behavioral context: the payment model ($0.003 USDC via x402, failed calls not charged) and the max limit of 50. It stops short of 5 only because it omits pagination/rate-limit 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 compact and front-loads the core operation, then the available facets, then return fields and cost. Every sentence carries information, though the enumerated result fields overlap heavily with the existing output schema.

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 read-only search tool with an output schema and full schema coverage, this is close to complete: it covers operation, filters, cost, and limit. The lingering gap is sibling differentiation (law_ecfr) rather than anything blocking invocation.

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%, so the schema already documents all six parameters in detail. The description largely restates the schema's facets and does not add syntax or format hints beyond what is present, so the baseline of 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 states a specific verb+resource ('Searches Federal Register documents') and enumerates the filterable facets (terms, agency slug, document type, date range), so the tool's function is unambiguous. It does not, however, differentiate itself from the law_ecfr sibling or other legal/regulatory search tools, so it stops short of a 5.

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?

Usage is implied by the listed filters (searching US federal regulatory documents by term/agency/type/date), but the description never states when to prefer this over alternatives such as law_ecfr or congress. No explicit when-to-use or when-not-to-use guidance is provided.

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