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

With no annotations, the description carries the full burden and does disclose the critical behavioral fact that this is a paid call ($0.001 via x402/USDC on Base), plus the 25-pair cap and default behavior. It omits error handling, invalid-symbol behavior, and rate limits, leaving some gaps.

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?

One dense but front-loaded sentence: cost and capability lead, batching rationale trails. Every clause carries information, though the parenthetical symbol list makes it heavier than necessary and could have been left to the schema.

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 single optional-parameter, annotation-free, no-output-schema tool, the description covers payment, batching limits, and defaults. The one notable omission is the shape of the returned price snapshot, which no output schema documents; otherwise an agent has what it needs to call it 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%, so 'symbols' is already documented as comma-separated BASE-QUOTE. The description adds meaning the schema does not: the maximum of 25 pairs and the default 10-major set when the parameter is omitted, which matters for an optional param.

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 ('multi-asset USD price snapshot in ONE call') with concrete scope: up to 25 pairs and the exact set of 10 default majors. It also implicitly separates itself from the per-pair sibling get_crypto_price by noting the batch advantage, so an agent can choose 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 clear usage context — 'Batch beats per-pair calls for portfolio and dashboard agents' — which tells the agent when this tool wins. It does not explicitly name or exclude a sibling alternative (e.g. get_crypto_price), so guidance stops short of full when/when-not routing.

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