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

The annotations already indicate readOnlyHint=true and destructiveHint=false, and the description adds substantial behavioral context beyond that: per-row attribution of prices to provider-stamped sessions, open interest to its separate effective date, IV/greeks being provider model values computed at fetch time, and price-feed differences across Pro/Plus/Free. It also warns that daily figures are not live quotes, which is valuable for an agent deciding whether this tool fits the user's need.

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 front-loaded with the tool's purpose and then layers parameter behavior, return-value caveats, and data-feed differences in a logical order. Every sentence adds useful information without repetition or filler, and the length is justified by the complexity of an options chain tool.

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?

Given there is no output schema, the description adequately explains what each row contains, how dates are attributed, how values like IV and greeks behave, and how the data differs across subscription tiers. It also covers all input params relevant to choosing and filtering the chain, leaving little ambiguity about what the agent should expect when calling this tool.

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 each parameter is already documented structurally. The description adds meaningful semantics on top of that: expiration format and default behavior, minStrike/maxStrike usage to reach the wings, type to select calls/puts, and the maxResults behavior where larger chains return near-the-money contracts. This goes beyond the schema's basic descriptions, though not every parameter gets extended detail.

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 a specific verb and resource: get the option chain (calls and puts) for a stock for one expiration, including strike, greeks, implied volatility, open interest, and latest daily price. It clearly distinguishes itself from related siblings like GetOptionExpirations and GetOptionContract by emphasizing the 'ONE expiration' scope.

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 gives explicit usage context: it defaults to the nearest expiration, instructs how to pick another expiration, and points to GetOptionExpirations to list expiration dates. It also explains when results are limited to near-the-money contracts and how to narrow the chain, though it does not explicitly contrast with GetOptionContract or GetLiveQuote for single-contract or live-price needs.

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