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

With no annotations, the description carries the full burden and does well: it discloses pricing ($0.02 USDC after a daily free allowance), the exact 402 recovery loop (pay memo, re-call with SAME args plus payment_tx), and that a Bearer key bypasses payment. It also pre-empts a likely expectation by stating Greeks are not available. Missing only rate/pagination or caching details.

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-loads the payload contents in one sentence, then a compact payment paragraph. Every line is functional, though the parenthetical about Greeks duplicates part of the opening list and could be tightened.

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-shape detail is unnecessary, and the description covers the non-obvious payment flow, auth alternative, and data gaps. What remains uncovered–caching, response size, or failure modes beyond 402–is minor for a required-1-param read tool.

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 baseline is 3, but the description adds real meaning for payment_tx (only used when re-calling after a 402, with identical args) that the schema alone does not convey. Ticker and expiry semantics are left entirely to the schema.

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 ("Get the option chain for a ticker") and enumerates the returned fields (strike, bid/ask, volume, OI, IV, expiries), which clearly separates it from siblings like quote or price_history. The explicit caveat that Greeks are absent further sharpens what this tool is.

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 implied by the resource–option chains are for options analysis versus quote/price_history for spot and history–but no sibling is named and no when-not-to-use condition is given. The payment/auth instructions are operational rather than selection guidance.

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