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

Goes well beyond the readOnly/idempotent annotations: distinguishes servable from ambiguous answers, says ambiguous identities return candidate EMA product numbers at no cost, quotes the toll preview amount and notes you only pay for delivered answers. It also gives the equivalent HTTP endpoint, which is useful for an agent reasoning about transport.

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 core framing (free pre-check for ema_record) is front-loaded, but the sentence is overloaded with parenthetical detail such as '$0.01 RULED (10000 USDC units / 68000 lamports)' that is largely irrelevant for a tool advertised as free. Dense run-on phrasing costs readability without adding decision value.

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?

With no output schema, the description does the necessary work of describing the two answer shapes (servable vs ambiguous) and the freshness/deliverable payload, plus cost behavior. It stops short of explaining the inputs or what a validation failure looks like, which leaves a gap for a 3-param tool.

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 0% and the description never explains the three inputs (ema_product_number, name, inn) or the anyOf requirement that at least one must be supplied. The only hint is that ambiguous identities yield candidate product numbers, which implies name/inn can be used for resolution but does not clarify which identifier is preferred.

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 role: a free pre-check twin of ema_record that performs validation, identity resolution, coverage and toll fingerprinting without writing records. That distinguishes it from the sibling ema_record. However, phrases like 'toll fingerprint' and 'deliverable shape' are jargon an agent must infer, keeping it short of fully self-explanatory.

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?

Establishes clear context: it is the free pre-flight counterpart to ema_record, so it is called before committing to the paid record path, and it explicitly says no payment or x402 challenge is required. It never states a when-not condition (e.g. when to skip preflight and call ema_record directly).

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