Option chain

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

Annotations already cover readOnly/idempotent/non-destructive/openWorld, so the safety profile is done. The description adds genuinely useful behavior beyond them: large results are stored rather than returned inline and the caller receives a result_id to fetch via results_query. It does not mention pagination behavior even though page_token exists in the schema.

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 tight sentences, front-loaded with what the tool returns, then the filtering constraint, then the result-storage behavior. No filler or restated field names.

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 steps in to explain the return contract (stored results plus a result_id for results_query), which is exactly the missing piece. Combined with the annotations and 100% schema coverage, an agent has what it needs to call this 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?

Schema description coverage is 100%, so the schema already documents every parameter including strike_min/max as inclusive USD values and expiration_from/to. The description only summarizes the same information ('strike range (USD)', 'expiration (exact or from/to)'), adding little beyond the structured fields.

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 resource ('option chain of one underlying') and the exact content of a row (greeks, implied volatility), plus the filter axes (type, strike range, expiration). This distinguishes it from siblings like options_snapshots, options_bars and reference_option_contracts.

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 clear operational guidance: 'Chains are large; filter by expiration and strike', steering the agent toward narrowing filters. It also routes the agent to results_query for retrieving stored output, but does not explicitly state when to prefer options_snapshots or options_bars over this tool.

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