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 material behavior beyond that: a hard cost of $0.003 USDC per call via x402 (a payment/authorization requirement an agent must plan for) and the fact that metadata is resolved from IPFS/Arweave/HTTP, implying latency and possible resolution failure. It does not describe error or rate-limit behavior, so it stops short of 5.

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, no filler, with the resource, scope and outputs front-loaded and the cost constraint placed as its own sentence. The first sentence is a dense multi-clause run-on, but every clause carries payload.

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?

There is no output schema, so the description correctly carries the return-value burden by naming both the collection-level fields and the token-level metadata fields. It is nearly complete for a 3-parameter lookup; the remaining gaps are the meaning/format of the required `contract` parameter and any error behavior.

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 only 33% – `chain` is documented in the schema and the description largely repeats the same chain list, while `contract` and `token_id` are bare in the schema. The description partially compensates by explaining what `token_id` unlocks (owner, resolved metadata), but `contract` (the required parameter) is never explained and no format guidance (address vs ENS) is given.

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 and resource (NFT lookup) plus the exact scope (Ethereum, Base, Polygon, Arbitrum, Optimism) and enumerates the returned fields, which separates it from solana_nfts by chain scope and from nft_floor by returning identity/supply rather than price. An agent can identify the tool 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?

The description conveys the usage pattern implicitly through the conditional "with token_id also the current owner and resolved metadata", so the agent knows the difference between a collection-level and token-level call. However, it names no alternative (nft_floor, wallet_nfts, solana_nfts) and gives no when-not-to-use guidance.

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