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

With no annotations, the description carries the burden and does well: it discloses the price source (DefiLlama aggregation) and the payment requirement (costs $0.002 USDC on Base via x402), which is important pre-call context. It omits rate limits, failure behavior for unknown symbols, and staleness/latency of the prices.

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?

A single front-loaded sentence covering capability, input forms, source, and cost with no filler. It is dense with parenthetical examples, which costs a bit of readability but nothing is wasted.

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 one-parameter read tool with no output schema and no annotations, the description covers inputs, limits, data provenance, and cost — the essentials an agent needs to invoke it. Remaining gaps (error handling, response shape, price freshness) are minor.

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 already documents the comma-separated format, but the description adds concrete examples for each accepted identifier form (symbols, coingecko:<id>, base:0x..., solana:<mint>) plus the 20-token cap that does not appear in the schema at all.

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+resource (current USD price and 24-hour change for crypto tokens) with an explicit scope limit (up to 20 tokens in one call) and names the underlying source (DefiLlama aggregated prices), so an agent can tell it apart from the per-chain token_snapshot siblings.

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 context for when this is the right call: batch pricing of up to 20 tokens in a single request. It does not explicitly name alternatives (e.g. eth_token_snapshot) or state exclusions, so it falls short of a 5.

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