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

Annotations already declare readOnlyHint and openWorldHint, and the description goes well beyond that: it discloses the external data dependency, the pricing model ($0.002 in USDC via x402 on Base/Solana/Arc), and crucially that failed calls are not charged. The accuracy caveat by pool type is behavioral context an agent cannot get from structured fields.

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-loads the core purpose and model, then the exactness caveats, then cost. The final pricing sentence is long and carries multiple facts (currency, chains, failure billing), but every clause serves a purpose for an agent deciding whether to call.

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?

An output schema exists so return values needn't be explained; parameters are fully described in the schema. The description supplies the missing context an agent needs — data source, model assumptions, accuracy limits, exclusions, and pay-per-call cost — so nothing material is absent.

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%, so pair, side, chain, amount, feePct and slippagePct are already documented in the schema. The description's only param-relevant remark is 'with a fee', which does not add semantics beyond the existing feePct definition, 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 specific computation (estimated output, price impact, minimum output) on a specific resource (one DEX pair), and names the model (constant-product x*y=k with fee) and data source (DexScreener reserves). It also scopes validity, distinguishing exact pools (Aerodrome volatile, Uniswap V2) from approximations (v3/v4) and an excluded venue (Raydium).

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?

Gives clear conditions on when results are trustworthy (constant-product pools) versus approximate (concentrated liquidity) and an explicit exclusion (Raydium is not covered). It stops short of naming a sibling tool to use instead for those excluded cases, but the applicability guidance is otherwise explicit.

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