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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), and the description goes well beyond them by disclosing cost and throttling ('25 free calls a day, then $0.01 USDC per call (x402)') plus the real-world consequence of misuse. This is exactly the contextual layer annotations cannot express.

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?

Front-loads the trigger condition and the risk of misuse before capability, example and cost. Dense but every clause carries weight; the trailing 'Outputs explained: GET /api/tools/whats_this' is the weakest element, reading more like a doc link than guidance.

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 still conveys the shape of the return ('what any address is... with its key facts') and points to an explanation endpoint for the rest. That is adequate for a single-address lookup, though the returned fields themselves are never enumerated.

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 100%, so both the address and network parameters (including the mainnet-beta default and devnet caveat) are already fully documented in the schema. The description's USDC example illustrates what the address might be rather than adding format or syntax detail, so the schema remains the primary source.

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 broad resource: identifies what any address is ('wallet, token account, token, program, stake account and more') with key facts. It implicitly subsumes single-purpose siblings like wallet, find_token and token_account, but never names them, so the agent must infer the routing decision itself.

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?

Gives a clear triggering condition ('run when unsure what an address is, before sending to it or passing it on') and a concrete consequence that motivates it (SOL sent to a token or program address can be lost for good). Strong when-to-use, but no explicit when-not-to-use or named alternative tools.

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