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

With no annotations provided, the description carries the full burden and adds useful behavioral context: it is realtime, costs $0.001 USDC on Base via x402, and should be polled roughly every 10 seconds. It does not cover error behavior, rate-limit enforcement, or response structure beyond listing key fields, so some gaps remain.

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?

Three short sentences, front-loaded with the core purpose and followed by usage cadence and cost. Every sentence adds distinct, actionable information with no redundancy.

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 simple one-parameter data tool with no output schema and no annotations, the description covers purpose, return fields, polling cadence, and cost. It could say more about the response shape or failure modes, but it is sufficient for correct invocation.

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% and the single parameter product_id is fully documented in the schema with examples. The description adds no parameter meaning beyond what the schema already provides, so the baseline of 3 is appropriate.

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 the specific resource (realtime crypto top-of-book data) and its fields (best bid, best ask, sizes, sequence), so the agent knows exactly what data is returned. However, it does not explicitly differentiate this tool from siblings like crypto-price, crypto-market-snapshot, or canonical-crypto-spot-price.

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: designed for repeated pre-execution polling, with a suggested refresh interval of about 10 seconds during active trading. It does not name alternatives or state when not to use it, but the intended scenario is unambiguous.

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