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

With no annotations supplied, the description carries the behavioral burden and does a fair job: it discloses the paid model, price, payment chains, that no credentials are required, and that failed calls are not charged — exactly the kind of commercial and auth context an agent needs. It stops short of disclosing rate limits, response format, or what a failure looks like on the wire.

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?

It is front-loaded with the most decision-relevant token ('Paid') and then packs scope, fields, price, auth, and failure policy into a few dense clauses with no filler. The trailing endpoint URL is arguably redundant with tool configuration metadata and is the only sentence that doesn't earn 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?

For a three-optional-parameter read tool with no output schema and no annotations, the description covers what an agent needs to decide and pay: what data comes back at a field level, the cost and payment rail, and the no-credential requirement. Remaining gaps — pagination behavior and exact response envelope — are moderate given there is no output schema to lean on.

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%, so sort, limit, and min_tvl_usd are already documented in the schema and the baseline of 3 applies. The description only indirectly signals that APY/TVL are the sortable dimensions by listing returned fields; it adds no format, unit, or default detail beyond the schema.

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 names a specific resource and scope: live DeFi yield pools for the 'tydro' protocol across chains, with APY, TVL, and 7d APY change from DefiLlama. That is concrete enough to distinguish it from the many per-protocol siblings, though it never explicitly states 'use the other buy_yields_protocol_* tools for different protocols' and relies on the name embedding to make the scoping obvious.

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?

It gives a real usage condition an agent must weigh before calling: this is a paid call at $0.01 USDC on Base or Solana, with no account or API key needed and no charge on failure. What's missing is any explicit alternative or when-not-to-use guidance (e.g. use a free/chain-level yields tool instead), so routing still requires inference from the sibling names.

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