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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description usefully narrows behavior to fixed protocol pairs per chain (only Aave V3 vs Compound V3 on the ~44 EVM chains, Kamino + staking on Solana), which is non-obvious context, but says nothing about data freshness or response shape.

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 short fragments, front-loaded with the core purpose, zero filler. The terse protocol/chain notation ('EVM: Aave V3 vs Compound V3 side-by-side') is efficient but slightly telegraphic.

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 an output schema present, return values need no explanation, and the single enum parameter is fully documented in schema. The description supplies the missing scoping context (which protocols are compared on which chain family), leaving little an agent needs beyond whether it should prefer defi.yields instead.

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?

Single optional 'chain' parameter with 100% schema description coverage, so the schema fully documents the enum and default ('base'). The description's breakdown of what each chain family returns is protocol context rather than parameter semantics, so the baseline 3 applies.

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?

Clear verb+resource: 'Compare DeFi lending rates across protocols', then names the concrete protocol pairs per ecosystem (Aave V3 vs Compound V3 on EVM, Kamino + staking yield on Solana). This is specific and distinguishes it from a generic yields tool, though it does not explicitly contrast itself with siblings like defi.yields or defi.aggregator that also deal with protocol rates.

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?

Usage is implied — the tool exists to do side-by-side protocol rate comparison — but there is no explicit 'use this when... / instead of defi.yields' routing. With nine defi.* siblings, a sentence naming the alternative would materially help selection.

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