Market data: options chain

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

With no annotations, the description carries the full burden and does reasonably well: it discloses that two providers are queried, that contracts are matched by strike and volume/OI compared, and that a null expiry falls back to each provider's nearest expiry. It does not cover failure/partial-failure behavior when one source is unavailable, or any rate/latency expectations for the dual fetch.

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?

Front-loaded summary sentence followed by tidy Args/Returns blocks; each line carries information. The Returns section partially duplicates what an output schema already provides, which is mild redundancy but not noise.

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 two-parameter read tool with an output schema, the description covers what to pass, what happens on null expiry, and how the two sources are reconciled. The remaining gap is operational edge cases (one provider failing, empty overlap) rather than core call correctness.

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 0%, so the description must compensate, and it does: symbol is identified as the underlying ticker and expiry is given an explicit ``YYYY-MM-DD`` format plus the semantics of null (each provider's nearest expiry). Only minor gaps remain, such as expiry validation or timezone conventions.

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 (options chain) scoped to a single expiry, and the opening line also discloses the dual-source mechanism (Finviz plus a TradingView/Yahoo endpoint). No sibling tool covers options chains, so an agent can place it unambiguously among the listed market-data tools.

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?

Usage is only implied: the line about comparing volume/open-interest 'so an agent can see whether the two sources agree on open positioning' hints at the cross-source validation use case. There is no explicit when-to-use, when-not-to-use, or reference to alternatives (e.g. stock_quote or technical_analysis) for simpler needs.

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