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

Annotations already mark it read-only and open-world, but the description adds valuable context: it is a snapshot (not streaming), depth is computed only from returned levels, max 100 levels per side, and pricing is $0.002 per successful call via x402 with failed calls free. These details go well beyond the annotations.

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?

The description is a single dense paragraph with no wasted sentences. It front-loads the core purpose and outputs, then adds scoping and pricing details in a logical 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?

Given the full input schema and the presence of an output schema, the description covers everything an agent needs: what data is returned, the snapshot nature, level limits, and payment mechanics. No critical behavioral gaps remain.

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 both parameters are fully documented in the schema. The description only reinforces 'one pair' and 'up to 100 levels per side', which adds little beyond the schema's own descriptions; baseline 3 is appropriate when the schema does the heavy lifting.

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?

The description states a specific verb (snapshot), resource (Binance spot order book), and concrete outputs (best bid/ask, spread, USD depth, 24h stats). It explicitly scopes to Binance spot and excludes merged multi-exchange books, distinguishing it from aggregated depth 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?

The exclusion 'Snapshot only; Binance market data, not a merged multi-exchange book' clarifies when not to use it, and the overall context implies appropriate use for Binance-specific depth. However, it does not name a specific alternative (e.g., crypto_coingecko_market_depth or crypto_hyperliquid_perps_depth) for merged or non-Binance needs.

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