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

With no annotations, the description carries full behavioral burden. It discloses that the tool reads from the contract (read-only), returns classified tokenURI types (ipfs/on-chain/http), and includes pricing ($0.09 via x402). It does not detail error handling or response format, but the core behavior is well communicated.

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 compact yet information-dense, front-loading the core purpose and cost, then explaining the on-chain advantage and supported chains. Every clause serves a purpose, and it is easy to scan.

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 NFT lookup with no output schema, the description covers the key aspects: what data is returned, the source (contract), the freshness benefit, and supported chains. It stops short of describing the exact response shape or error cases, but overall it is complete enough for an agent to invoke correctly.

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 75%, with chain, contract, and token_id already described. The description adds some value by listing supported chains and emphasizing token ID flexibility (decimal/hex), but x_payment remains undefined and no further parameter detail is provided. The baseline of 3 is appropriate given high schema coverage.

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 clearly states what the tool does: determines NFT ownership and metadata (ownerOf, tokenURI, collection name/symbol) in one call. It specifies the resource (NFT on a given contract) and distinguishes itself from sibling chain tools by focusing on NFT-specific data.

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 implies when to use this tool: when you need current on-chain data, 'correct for tokens minted seconds ago and collections no marketplace has indexed.' It does not explicitly name alternatives or exclusions, but the freshness angle provides clear context for selection.

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