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

Annotations only assert readOnly and openWorld, so the description carries the behavioral load and does so well: it details the returned metrics, notes the budget is fee-inclusive, warns that venue-side rounding varies with actual fills, and disclaims cross-venue equivalence. These are non-obvious traits an agent needs before relying on the quote.

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?

Front-loads the core action and keeps the caveats to short trailing sentences; every clause is informative. Slightly dense, but no filler and the routing hint is well placed at the end.

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, yet the description still summarizes the returned fields and flags the rounding/equivalence caveats, covering everything needed to call the tool correctly on a four-parameter, single-venue quote operation.

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 already 100%, so baseline is 3, but the description adds meaning beyond it by qualifying 'side' as the outcome to buy and tying market_id to its origin ('Polymarket market id or Kalshi ticker returned by search'). The amount_usd all-in-with-fees semantics are elaborated on the fee-inclusive budget.

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 and resource ('walk the current public order book for an all-in cash-sized BUY quote on one exact contract') and scopes it to a single venue, cleanly separating it from compare_executable_quotes. An agent can identify the operation and its scope without opening the schema.

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 names the alternative tool and the condition that selects it: 'Single venue only; to compare both venues for the same contract use compare_executable_quotes.' It also clarifies where market_id comes from ('returned by search'), removing ambiguity about input sourcing.

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