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

Adds significant value beyond annotations: discloses cost ($0.002 USDC per successful call), payment method (x402 on Base, Solana, or Arc), and that failed calls are not charged. Also clarifies excluded data. Does not cover rate limits or response format, but output schema exists.

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, front-loaded with purpose, then exclusions, then pricing. Every sentence adds necessary information without waste.

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?

Given zero parameters, readOnlyHint and openWorldHint annotations, and an output schema, the description is complete enough: it defines the snapshot's contents, what is excluded, and the cost model.

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?

No parameters, so baseline 4 applies. Description provides no additional parameter details because none exist, which is appropriate.

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 resource and scope: Lido stETH APR and beacon chain finalized/justified epochs with finality flag. It distinguishes from broader yield tools by explicitly excluding validator queue and churn, but does not name a sibling alternative.

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 implicit guidance by noting what is not reported (validator queue and churn), but does not explicitly state when to use this tool versus alternatives like crypto_lido_steth_peg or crypto_defillama_yields.

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