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

Annotations cover the safety profile (readOnly, idempotent, non-destructive), and the description goes well beyond them: it discloses the response payload (buy amount, network-cost bps, size-impact estimate, decision, evidence, warnings, freshness), the staleness caveat ('Quotes can change'), the absence of signing/advice, and the monetization model ($0.03 USDC per call via x402 V2 with separately authorized payment). That cost/auth/freshness context is exactly what annotations cannot express.

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 the core action, then use conditions, exclusions, pricing, and a fallback, each in a clause that earns its place. Dense but with zero filler and a clear priority order.

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-value detail is not needed, and the description covers purpose, usage, cost, staleness, and safety. The one real gap is per-parameter semantics for the 6-param input, which matters for a swap tool with required token addresses and decimals.

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 0% and 6 parameters (5 required) are present, so the description carries the full burden — but it only implies that 'amount' is the exact-in sell amount and never explains routingId, the two token addresses, or the decimals fields. Parameter meaning is largely left to the agent to infer.

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 — 'Analyzes current Base ERC-20 exact-in swap quotes without executing trades' — and pins the scope by explicitly ruling out execution. An agent can distinguish it from signal_layer_router and the other siblings without opening schemas.

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 an explicit trigger ('Before an exact-in ERC-20 swap on Base when... execution conditions, network cost, and size sensitivity matter'), explicit exclusions ('Do NOT use when: generic historical prices, personalized investment advice, or a signed transaction'), and names an alternative ('use the free signal_layer_router'). This is full when/when-not/alternative coverage.

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