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

Adds meaningful behavioral context beyond annotations: 'No auth, no spend', 'confirms settlement only', and explicitly lists what it does not verify. Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and the description adds no contradictions.

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 sentences, each earning its place. Front-loaded with the core purpose, then scope expansion, then safety and limitation caveats. No redundant phrasing or filler.

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?

Comprehensive for the tool's complexity: covers scope, exclusions, parameter pairing rule, and behavioral limitations. Minor gap: no description of what the tool returns (e.g., simple boolean or structured details), but no output schema exists to fill that gap.

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?

Even though schema coverage is 100%, the description adds critical semantics not in the schema: the constraint that 'amount must be accompanied by a payTo or payer' and that amount is 'matched as >='. This directly affects how to set parameters together.

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+scope: 'check that a Base-mainnet USDC transfer settled on-chain' with optional matching. Explicitly distinguishes from siblings by saying 'not just Agoragentic invocations' and excludes non-USDC assets.

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?

Provides clear context for when to use (any USDC-settled x402 payment on Base, yours or received) and exclusions (non-USDC assets out of scope). Does not explicitly name alternative tools, but the scope and limitations ('does not verify service delivery, output quality, or counterparty identity') help decide applicability.

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