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

Annotations already cover safety (readOnly=true, destructive=false, openWorld=true), so the description rightly adds what they don't: the $0.1 USDC cost on Base, that the tool call itself is free, and the x402 402→PAYMENT-SIGNATURE→delivery flow. That is meaningful operational context beyond structured fields, though rate limits or failure modes are unaddressed.

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?

Short, front-loaded with purpose then usage then pricing/payment mechanics. Sentences are dense but each earns its place; the x402 flow sentence is somewhat compressed but functional.

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 one-parameter lookup with no output schema, the description covers purpose, audience, cost, and the payment/return mechanism (x402 URL to GET). What it omits is what the 'plain flags' actually contain, though it gestures at the result shape.

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?

Only one parameter and schema coverage is 100%, so the schema already documents 'mc' fully. The description repeats 'MC/docket number' but adds no format, validation, or example beyond the schema. 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+resource (broker authority check) scoped to FMCSA data by MC/docket number. The 'broker' vs sibling 'check_carrier_authority'/'check_carrier_basics' distinction is implied by the resource noun but never made explicit, so an agent must infer which sibling to pick.

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?

Gives a clear scenario: 'The check a carrier or factoring agent runs before accepting a load from an unknown broker.' That establishes when to use it. It stops short of naming a preferred alternative or an exclusion (e.g. when to use check_carrier_authority instead).

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