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

Annotations only declare readOnlyHint=true, and the description adds meaningful context about the tool's behavior: it computes a straddle-implied 1-sigma move and includes specific components. However, it does not disclose details like data freshness, error behavior, or whether multiple expiries return a list, though these are partially covered by the schema. No contradiction with 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 two sentences, with the first sentence front-loading the core purpose and output components, and the second listing concrete use cases. Every sentence adds value, with no filler or redundancy.

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?

Since there is no output schema, the description compensates by listing the key return fields (range, bounds, straddle price, ATM IV). It does not explain list vs. single-expiry behavior in the description, but the schema covers the expiry parameter, and the tool's simplicity keeps the description adequately complete. Slightly more detail on the response format would push it to 5.

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 100%, so the schema fully documents apiKey, expiry, and symbol. The description adds no additional parameter-level meaning beyond the schema, which is acceptable given the high coverage. The mention of 'per expiry' aligns with the expiry parameter but does not provide extra syntax or format details.

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 starts with a specific verb and resource: 'Straddle-implied expected move per expiry' and enumerates the exact outputs (1-sigma dollar and percent range, upper/lower bounds, straddle price, ATM IV). This is distinct from sibling tools like get_realized_vol (realized range) or get_volatility (implied vol), so it differentiates well.

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 explicitly states intended uses: 'Use to size trades, evaluate premium levels, or compare market-implied move vs realized range.' This provides clear context for when to invoke the tool, though it does not mention when not to use it or name specific alternative tools.

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