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

Annotations already declare read-only, idempotent, non-destructive behavior, yet the description adds substantial operational context beyond them: 15 s cache, the 65,000 gas-unit assumption (not measured), Solana lamport fees plus new-token-account rent, per-chain error handling with failing chains listed last, 502 on all-fail, 422 on bad input, latency 1-5 s, price, and free tier. This is unusually rich disclosure.

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 purpose and the sibling alternative before dense operational detail. Every sentence carries information, though the pricing/error/latency block is packed tightly and reads as a spec dump rather than prose.

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-format explanation is unnecessary; the description still covers error semantics, caching, cost, rate limits, and performance. For a 3-param read-only comparison tool, nothing an agent needs to call it correctly 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%, so the schema already documents token, amount (including that it is informational only), and chains. The description adds only the Solana lamport/rent detail, which is not a parameter concern. Baseline 3 applies when the schema does the heavy lifting.

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 (compare) plus resource (USDC/USDT transfer fees) and enumerates the exact chains covered. It explicitly distinguishes itself from the sibling check_stablecoin_peg by naming it as the tool for peg status, so an agent can route correctly 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?

Names the alternative tool and the condition that selects it ('For peg status use check_stablecoin_peg'), and clarifies the default scope (all six chains). When-to-use and when-to-use-something-else are both explicit.

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