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

Annotations only declare readOnlyHint and openWorldHint, and the description adds real behavioral context beyond that: the model used, that every intermediate number (sigma, z, formula, caveats) is surfaced, and tier-based limits on levels, vol multiplier, and saved scenarios. It does not cover latency, rate limits, or failure modes, so not a 5.

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-loaded with the core computation, and the tier restrictions are packed into one clause. It is dense but slightly run-on with stacked parentheticals, which costs a little readability.

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 does the work of describing the return (touch probability, above/below probability, and the full calculation shown), which is what an agent needs to know. The remaining gaps are input-side details (asset format, horizon semantics) rather than output expectations.

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 60%, and the description reinforces a few parameters: level count limits, the vol multiplier concept, and saved scenarios. It does not clarify the asset string format or what horizon_hours measures, so it only partially compensates for the coverage gap.

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 computational verb and resource: probability a market touches given price levels within a horizon, plus above/below finish probability, and names the method (driftless lognormal, reflection principle, realised hourly volatility). This is clearly distinguishable from every sibling, which are data-retrieval tools rather than a probability calculator.

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?

Gives concrete context: any market OwlChart covers, with examples (BTC, ETH, SOL, WLFI, AAPL, gold), and spells out the trial vs Scenario Engine/Builder/Scale/PRO split of one level vs up to eight levels. It stops short of naming alternative tools or stating when not to use it, so it falls 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.