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

Annotations already declare readOnlyHint/idempotentHint and destructiveHint=false; the description adds useful scope ('one underlying', 'optional expiration') and the returned fields. It does not disclose grouping, ordering, or pagination, but that is less critical given the read-only annotations.

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 front-loaded sentence states the main action and the differentiating scope before adding the useful field list. There is no redundant wording or restatement of the tool name.

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 chain retrieval with no output schema, the description lists returned fields but not response shape or the meaning of `limit`. This is serviceable but leaves an agent to guess at a key optional parameter and the output structure.

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 only 50%; the description adds 'optional expiration' but says nothing about `limit` or `exchange`. In particular, `limit` is unexplained in both the schema and description, so an agent cannot tell whether it caps expirations, contracts, or something else.

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 uses a specific verb ('Get') and resource ('calls and puts for one underlying'), and it names the returned data fields. This clearly distinguishes the options-chain tool from siblings like market.options_flow and market.quotes without needing to open the schema.

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 opening 'Get calls and puts for one underlying and optional expiration' states a clear use case: retrieve an options chain for a single symbol, optionally filtered by expiration. It does not explicitly name alternatives or exclusions, so it doesn't reach 5.

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