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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful context by specifying that data is read on-chain, which chains are covered, and the comparison against a 3-month Treasury bill. It also hints at the interpretive output around leverage demand, going beyond what the annotations alone provide.

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 a single sentence that packs the essential elements: asset, protocol, chains, comparison benchmark, and interpretive angle. It is slightly run-on with a colon, but every part adds value and the most important information is front-loaded.

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 zero-parameter, read-only tool, the description gives enough context: what is measured, where it is read, and what the spread indicates. It does not detail the exact return shape or whether the data is historical or current, but no output schema exists and the tool's scope is narrow.

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?

The tool has zero parameters and 100% schema description coverage, so parameter semantics are not a burden on the description. The baseline of 4 applies because there is nothing missing for an agent to invoke the tool correctly.

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 the specific resource: USDC lending and borrowing APR on Aave v3 across five named chains, compared against the 3-month Treasury bill. It identifies the exact metric (DeFi vs TradFi dollar spread) and its interpretive angle (leverage demand), making it distinguishable from the broader market and treasury sibling tools.

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 its use case: when an agent needs the DeFi vs TradFi dollar spread and what it signals about leverage demand. It does not explicitly name alternatives or exclusions, but the context is clear enough given the unique scope.

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