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

With no annotations, the description carries the full burden and does well on the commercially critical behavior: it is a paid call at $0.002 USDC on Base or Solana, requires no account or API key, and failed calls are not charged. It omits rate limits, caching/freshness of the DefiLlama data, and any note on permissions, which keeps it short of a 5.

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 'Paid.' and a single dense sentence covering scope, fields, and data source, followed by cost/payment facts. Efficient overall; the raw URL is of marginal value for an MCP caller but is harmless in the final position.

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 3-param, no-annotation, no-output-schema tool, the description covers the important unknowns: that it is paid, how to pay, that failures are free, and what the rows contain. Response shape and ordering/pagination details are not stated, but with all parameters defaulted and documented in the schema, an agent has enough to invoke it correctly.

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 fully documented in the schema with defaults. The description adds no additional meaning (e.g., how sort interacts with min_tvl filtering or what the default TVL floor implies for results), 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?

The description names a specific verb (get live DeFi yields) and a specific resource scope (protocol 'concrete', its pools across chains), and states the returned fields (APY, TVL, 7d APY change). It is clearly distinguishable from coin-price siblings, though it never explicitly contrasts itself with the chain-, token-, or top-level yield siblings.

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 by the scoping ('for concrete'), and the pricing/payment lines help an agent decide whether to spend on the call. However, there is no explicit guidance on when to pick this over buy_yields_chain_*, buy_yields_token_*, or buy_yields_top, and no stated exclusions.

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