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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds valuable non-annotation context: the tool is paid ($0.001 USDC on Base via x402), which an agent must know before invoking. It stops short of describing error or payment-failure 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?

Two tight sentences with no filler; the resource and returned fields come first, followed by the payment note. Every clause earns its place.

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 helpfully enumerates return fields (time, gas, tx count) and discloses the payment requirement, which is enough to call it correctly. Minor gap: it does not say what happens when the optional block argument is omitted.

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 0%, so the description must carry the burden – and it does, by documenting that the block argument accepts a number or a named tag (latest, safe, finalized). This meaningfully compensates for the empty schema description, though it doesn't state the default when the optional param is omitted.

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: returns a Base block header, and names the returned fields (time, gas, tx count). It is clearly distinguishable from siblings like base_tx or base_receipt, though it does not explicitly name those alternatives.

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?

No guidance on when to use this versus base_tx, base_receipt, or base_gas, and no prerequisites stated. The purpose is inferable from the description but no usage conditions or exclusions are provided.

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