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: it discloses the paid model ($0.005 USDC on Base or Solana), that no account or API key is required, and that failed calls are not charged — behavior an agent needs before invoking. It stops short of rate limits or response format details, hence not 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?

One compact block with 'Paid.' front-loaded as the most decision-relevant fact, followed by scope, return fields, pricing, auth, and endpoint. Every sentence earns its place and nothing is redundant.

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 zero-required-param read tool with no output schema, the definition covers cost, auth, data source, and the returned metrics (APY, TVL, 7d change), which is enough to call it correctly. Only minor gaps remain around rate limits and result ordering beyond the sort parameter.

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 coverage is 100% and all three parameters (sort, limit, min_tvl_usd) are documented with types and defaults in the schema itself. The description adds no parameter-level meaning beyond that, 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?

States a concrete verb and resource — 'Live DeFi yields for gmx-evm: its pools across chains with APY, TVL, 7d APY change' — so the agent knows exactly what data comes back. The protocol-scoped nature distinguishes it implicitly from the chain_ and token_ yields siblings, though it never names them.

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 gives useful operational context (cost, payment chains, no API key needed) that tells the agent it can call this freely. However, it offers no explicit guidance on when to choose this protocol-scoped tool over buy_yields_chain_* or buy_yields_token_*, and no exclusions or prerequisites.

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