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

No annotations exist, so the description carries the full burden — and it does real work by enumerating exactly what is returned (depth bands, spread bps, average fill price, slippage) and by disclosing the venue constraint (only OKX, Gate, Kraken). It is silent on failure modes for unsupported pairs, rate limits, and whether results are snapshot-only, which is a moderate gap for an unannotated tool.

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 dense sentence that front-loads the venues and the core observation set. Every clause maps to an output metric, so nothing is wasted, though the run-on structure makes it slightly harder to scan than a short bulleted breakdown.

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?

An output schema exists, so return values needn't be explained, yet the description still summarizes them helpfully. Combined with an unannotated, all-optional 3-parameter schema, the definition is sufficient to invoke correctly; only pair-format and error-behavior details are missing.

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 0%, so all three parameters (pair, venue, size_usd) are undocumented in structured fields. The description partially compensates: it names the valid venue set and clarifies that size_usd is a USD notional used for slippage/fill computation. It never specifies the pair format (e.g. BTC-USDT) or default behavior when venues are unsupported.

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 names a specific resource and verb set — spot order book depth with best bid/ask, spread in bps, USD depth at three thresholds, and fill/slippage modeling for a given USD size. An agent can tell this is a liquidity-measurement tool, not a price lookup. It does not explicitly contrast itself with near-neighbors like exchange_ticker or markets_snapshot, which keeps it from a 5.

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?

Implicit usage is clear from 'slippage to market-buy or sell a given USD size' — you call this when sizing a trade. But there is no explicit when-to-use/when-not, no mention of how it differs from exchange_ticker or crypto_candles, and no guidance on pair format or venue availability limits beyond listing three venues.

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