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

Annotations cover the safety profile (readOnlyHint, openWorldHint), but the description adds real context: risk_level is explicitly flagged as a heuristic and the agent is told to run token_security on the pool token before depositing. It also discloses result ordering (APY descending) and the upstream source (defillama).

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-loaded with the core purpose, then cleanly sectioned into Use when / Not for / Returns / Example. The inline example response partly duplicates the Returns line, making it slightly longer than strictly necessary, but every section is scannable and earns its place.

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 fully compensates by enumerating returned fields (protocol, apy, tvl_usd, chain, risk_level), ordering semantics, and a concrete example payload including the source. Nothing an agent needs to call or interpret the result is missing.

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 all three parameters (token, chain, min_tvl) are documented in the schema with defaults and formats. The description adds only 'for a given token', which does not extend parameter meaning, so 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?

States a specific verb and resource ('Find best DeFi yield opportunities across protocols for a given token') and explicitly distinguishes itself from the sibling defi_tvl, which covers protocol TVL rather than pool APYs. An agent can route between them without opening either schema.

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?

Has explicit 'Use when' and 'Not for' clauses naming the alternative tool (defi_tvl) and the condition that selects it. It also proactively routes to token_security before depositing, which is genuine decision guidance rather than restated purpose.

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