get_options_chain

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

Annotations already cover the safety profile (readOnlyHint, idempotentHint), so the description only needs to add operational context — and it does: the response payload is fully enumerated despite there being no output schema, and the ranking rule ('liquid call/put contracts') and default expiry behavior are disclosed. Missing are failure modes (invalid ticker, empty chain), data staleness, and any rate-limit or size caveats.

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?

A single dense paragraph, front-loaded with the resource and return payload, then the filters. The long return-field enumeration earns its place given no output schema, though the parenthetical Greek list is heavier than needed since 'Greeks' plus one example would convey the same.

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?

For a read-only lookup with no output schema, enumerating the returned fields and the default behavior when expiration is omitted is exactly the completeness needed. It stops short of error/staleness behavior expected of market data, which keeps it below a 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 coverage is 100%, so every parameter already has its own description including defaults and the liquidity/proximity ranking for limit. The description restates the same filter set (expiration YYYY-MM-DD, option_type call/put/all, limit) without adding syntax, constraints, or interaction effects beyond the schema — the 3 baseline is appropriate.

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 (option chain, expiration dates and Greeks lookup) scoped to 'a single underlying ticker', and enumerates exactly what comes back (strike, bid, ask, IV, volume, OI, delta/gamma/theta/vega/rho). It doesn't explicitly distinguish itself from siblings like get_quote or screen_market, so the agent must infer the boundary from the word 'single underlying'.

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?

Use is implied by the resource description rather than stated: an agent can infer this is the tool for options data on one ticker, but nothing says when to prefer get_quote or screen_market instead. The 'Omit expiration to return available expiration dates' note is the closest thing to conditional guidance, and it is framed as parameter behavior rather than tool selection.

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