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

Annotations only cover readOnlyHint and openWorldHint; the description adds substantial behavior beyond that: it refuses to substitute a different contract, returns found=false with reason=no_such_expiry plus nearest available_expiries, names the failure conditions (no open interest, no bid, strike does not exist), and discloses that output is analysis rather than a trade recommendation.

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 with the core action and sibling differentiation, then failure modes in priority order; nearly every clause carries information. It runs long and the QQQM/expiry example could be tightened, but there is no filler.

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 does the work of enumerating returns (live quote, Greeks, premium, collateral, annualized yield, chance of expiring worthless, RENT score) and documents error paths. The remaining gap is the optional lang/risk/intent controls, whose effect on output and scoring is never described.

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?

Coverage is low at 29%, so the description must compensate; it does cover the required four (ticker, put/call, strike, expiry) and adds a real constraint — the expiry must be one the ticker actually lists, with QQQM as an example. However, it says nothing about lang, risk, or the scoring impact of risk/intent, so three of seven parameters remain underexplained.

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 first sentence states a specific verb and resource — price and score ONE named option contract (ticker + type + strike + expiry) — and explicitly contrasts it with explain_score and compare_candidates, which only cover engine-picked contracts. An agent can distinguish it from every named sibling without opening a 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?

It states exactly when to reach for this tool (an arbitrary user-specified contract, including deep ITM/far OTM strikes the screener would never surface) and when the siblings apply instead (contracts the engine already picked). It also closes the loop with explicit fallback behavior when the contract cannot be priced or the expiry is not listed.

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