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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds real context beyond them: the data source (Yahoo Finance via yfinance), that no API key is needed, the default-to-nearest-expiry behavior when expiry_date is omitted, and the exact field set returned. It does not cover error behavior for invalid symbols or rate limits.

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?

Lead sentence gives purpose and payload, followed by a short scannable use-case list, the prerequisite, the default, and provenance. Every line earns its place; only the blank-line-heavy formatting is slightly loose.

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?

An output schema exists, so return values need no explanation, and the description covers source, default behavior, and prerequisite adequately for a read-only tool. The one gap is the cluster of generic prompt/filter parameters in the schema that the description never addresses.

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 reported at 0%, so the description must carry the burden. It usefully documents expiry_date's YYYY-MM-DD semantics and the default behavior, and implies symbol is the underlying ticker, but it says nothing about the seven other parameters (wholesaler_ids, source_resource_id, exclude_fillers, etc.), some of which look irrelevant to an options chain and could confuse an agent.

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 ('Fetch the full options chain (calls and puts) for one expiry date') and enumerates the returned fields, so an agent knows exactly what it gets. It is clearly distinguishable from the sibling GetOptionsExpirations, which returns only dates.

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 when-to-use cases (options strategy research, IV across strikes, open interest for sentiment) plus a prerequisite ('Call GetOptionsExpirations first'). It does not name an alternative for cases where this tool is the wrong choice, but the exclusions are implicit in the narrow 'one expiry date' scope.

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