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

With readOnlyHint already true, the description adds behavioral nuance: Aave and bitcoin-collateral markets are read from contract state, while other venues come from DefiLlama, so small differences are expected. This explains potential inconsistencies in results beyond what annotations provide. No destructive or state-changing behavior is claimed.

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 pack necessary scope, caveats, and data-source info without fluff. The first sentence states the core function, the second provides context and expectations. Could be slightly tighter but remains well-structured and 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 one-parameter, read-only tool with no output schema, the description is adequate: it names the markets, explains data provenance, and warns about differences. It does not specify the output format, but that is not critical given the tool's straightforward comparative nature and the annotation covering safety.

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 100% and the sole parameter 'index' is already described as 'Only markets comparable to this index. Omit for all.' The description's mention of 'the same asset classes' loosely aligns with the index parameter but does not add new meaning beyond the schema. Baseline 3 is appropriate since the schema handles the semantics.

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 title and description clearly state the verb 'compare' and the resource: rates across the same asset classes on multiple chains. It names specific chains (Ethereum, Base, Hyperliquid, Solana) and additional reference rates (SOFR, repo, USDC/BTC borrowing), giving a precise scope that distinguishes it from siblings like get_rate or list_markets.

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 explicitly says 'Context only: none of these is ever a constituent of an SBOR index,' which tells the agent when not to use this tool (not for index constituents). It also notes data-source differences and expected variance, giving practical guidance. It does not name alternative tools explicitly, but the context is clear enough.

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