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

Goes well beyond the readOnly/openWorld annotations by disclosing the rate limit (3 free calls/day across all tools), the paid path ($0.0025 USDC via x402 or card credits) and exactly where payment goes (params._meta['x402/payment']), plus the upstream data source (GeckoTerminal). It stops short of describing response shape or failure behavior, but the output schema covers returns.

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?

The pricing/payment boilerplate occupies the opening and pushes the actual tool purpose to the second sentence, hurting front-loading. The eight-chain list is also enumerated twice ('Base, Ethereum, Solana...' and 'across 8 chains'), and 'Not financial advice' is filler for an agent.

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?

Given an output schema exists, the description need not explain returns; it still supplies chain coverage, the data source, cost model, and sibling routing. An agent has everything needed to decide and call 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 coverage is 100% and both parameters are documented in the schema, including the enum and the 'default base' note, so baseline is 3. The description's only added context is a prose restatement of the eight supported chains, which duplicates the enum rather than extending it.

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 and resource ('current USD price of one token by contract address from DEX data') plus the extra fields returned (market cap, FDV, volume, liquidity, 24h change). It explicitly differentiates itself from token-prices, token-price-history, and token-pools, so an agent can route without opening any 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?

The 'When to use' sentence names all three alternatives and the exact selection condition (one token vs up to 30 vs candles vs liquidity). Nothing about tool choice is left to inference.

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