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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds meaningful behavioral context: the cost ($0.02 USDC via x402), the payment rails (Base or Solana), the output categories (green/orange/red, grade, one-line summary, every ERC-20 allowance with spender), and the actionable revoke.cash link. It also discloses the limitation that NFT approvals are not covered. This goes well beyond the annotations.

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 description is dense but well-organized: cost and payment method are front-loaded, then the output details, then the exclusion. Every sentence adds information. It is slightly long but justified by the richness of the tool's output and the paid nature of the call. The 'Same as GET /v1/approvals' line is a useful compact reference.

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?

For a read-only audit tool with two fully documented parameters and no output schema, the description covers the key things an agent needs: what it costs, what chains it supports, what the output looks like, and what it does not cover. It does not describe pagination or rate limits, but for a simple audit call with a defined output shape, this is a minor 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?

Schema description coverage is 100%, so the schema already documents both parameters ('EVM chain to audit' and 'Wallet address (0x...)'). The description adds the chain list and the wallet use case, but it doesn't add deeper parameter semantics such as address format validation or chain-specific nuances. Baseline 3 is appropriate when the schema carries the full parameter documentation.

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 states a specific verb ('audit'), a specific resource ('open token approvals of an EVM wallet'), and the exact chains supported. It also explicitly excludes NFT approvals, which distinguishes it from any sibling that might cover broader approval types. The 'Same as GET /v1/approvals' line further anchors the tool's identity.

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?

The description gives a concrete use case ('for example your agent's own wallet as a periodic check') and states what is not covered ('NFT approvals are not covered'). It does not explicitly name sibling tools or say when to prefer an alternative, but the use case and exclusion provide clear context for when this tool is appropriate.

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