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

With no annotations, the description carries the full burden, and it delivers: it discloses the per-call cost and payment rail ($0.01 via x402 USDT on X Layer), the auth requirement (PAYMENT-SIGNATURE header on 402), retry behavior, and no-account friction. It also clarifies the ranking order and that the tool returns names, which is behavior beyond what the schema shows.

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 sentences, each carrying a distinct load: functionality, payment/auth/retry, and cold-start positioning with a pitch comparison. The most important purpose is front-loaded, and there is no filler.

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?

Without an output schema, the description still covers what is returned (names) and the ordering, plus cost, authentication, retry, and the primary use case. For a one-parameter, read-only scan tool, this is a complete and self-sufficient description.

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?

The schema already documents `limit` with default and max at 100% coverage, so baseline is 3. The description adds meaning by saying results are 'ranked most-high first,' so `limit` selects the top N of that ranked list. That is a small but useful addition, justifying a 4.

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 action and scope: 'Scan all 47 macro series and return those reading HIGHEST... ranked most-high first.' The 'HIGHEST' clearly contrasts with the sibling scan_bottoms, and the final sentence distinguishes it from pitch. This leaves no ambiguity about what the tool does.

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?

Explicitly frames when it is best used: 'BEST COLD START: you do not need to pick a symbol — this ranks the whole universe for you.' It contrasts itself with pitch ('tells you HOW MANY... this names them') and implies against symbol-specific alternatives. It does not explicitly name scan_bottoms or evaluate_symbol as when-not alternatives, but the cold-start context is strong.

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