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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds that results come from live precompile reads (not cached) and lists the verdict categories returned. It omits what happens on a malformed or non-B20 address and whether the call can revert or error, which would be useful for a mutation-free but external-state-dependent check.

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, zero filler, with the use case front-loaded and the return shape immediately after. The closing note about x402 is short and clearly secondary.

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 carries return-value duty and does so by naming the three verdict values and their source. The main remaining gap is edge-case behavior for addresses outside the B20 prefix or for failed precompile reads.

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% and there is only one parameter, so the baseline is 3; the description goes further by noting the 0xB200/0xB201 address prefix constraint, which the schema's generic hex pattern does not express. That adds real meaning beyond the structured field.

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 (check) and resource (Base B20 token), names the exact capabilities inspected (mint, seize, pause, block), and enumerates the possible verdicts. An agent can tell precisely what this tool does without opening the schema.

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?

"Before buying, holding, or accepting a Base B20 token" gives a clear, concrete trigger for invocation. It does not state when NOT to use it or what happens for a non-B20 address, but with no sibling tools the alternative-routing burden is minimal.

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