Exit cost at your size, per venue

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

Beyond the readOnly/idempotent annotations, the description discloses that values are interpolated from published quote depth, are never a book walk, and refresh only roughly hourly. It also includes a non-advice caveat, giving the agent an accurate picture of staleness and precision without contradicting 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?

Three sentences lead with the core function, then the returned data, then the estimation methodology and disclaimer. Every sentence earns its place and no wording is redundant with the title or schema.

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?

With no output schema, the description compensates by enumerating the key return elements (per-venue bps cost, cheapest/dearest venue, approximate dollar cost, venue spread) and the operational constraints (six BTC venues, hourly refresh, nearest rung). An agent has enough to invoke the tool and interpret its result correctly.

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 size_usd and its rung behavior completely, so the description adds little parameter-level detail beyond repeating that the size is in USD. This meets the baseline for full schema coverage but does not exceed it.

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 exactly what the tool computes: the current cost of selling a position of a given USD size, per venue, from live public order books for BTC across six venues. This clear resource-and-operation framing separates it from sibling tools such as liquidity_tiers or venue_concentration, even without naming them.

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 description makes the intended use evident ('what selling ... costs RIGHT NOW, venue by venue') and notes the data is refreshed roughly hourly, so an agent can decide it is appropriate for current exit-cost estimates. It does not explicitly state when not to use it or name alternatives, so it stops short of a 5.

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