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

Annotations already declare readOnly, idempotent, open-world, non-destructive, so the safety profile is covered. The description goes beyond them by disclosing dataset scope ("currently supported" authorities) and the per-call price of $0.0060 production USDC via x402 on Base mainnet, which matters for budgeting. It does not discuss latency, error behavior, or what a positive match implies beyond the negative scoping sentence.

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?

Three short sentences with zero filler: purpose first, scope boundary second, cost third. Each sentence carries a distinct piece of decision-relevant information and nothing is repeated from the 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?

An output schema exists, so return-value explanation is rightly omitted, and the description covers what is checked, the exactness of matching, dataset breadth, and cost. The only gap is any hint about how the optional authorities filter interacts with the default all-authorities behavior, which the schema largely handles on its own.

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 all three parameters carry their own documentation including the enum list and the note that CelerAPI never guesses a network. The description reinforces the exact-match requirement for the address but adds no format, normalization, or casing guidance beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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 names a specific verb and resource ("Checks whether an exact digital-currency address appears in the authoritative sanctions datasets") and explicitly delimits scope by ruling out blockchain-risk analysis and compliance determinations. An agent can tell exactly what question this tool answers, and no sibling in the list overlaps with sanctions screening.

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?

It gives clear context for use (sanctions-list membership) and explicit when-not boundaries ("not blockchain-risk analysis or a compliance determination"), which prevents over-trusting the result. It stops short of stating the triggering situation, e.g. screening a counterparty before a transfer, and there is no sibling alternative to route to.

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