Expiry calendar and settlement prices across venues

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

Annotations already declare readOnlyHint and openWorldHint, and the description adds meaningful behavioral context: a 60-day lookahead, grouping by date/venue/underlying, coverage of 54 venues, and inclusion of settlement prices. This goes beyond the annotations without contradicting them.

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?

The description is two sentences with no filler. The first sentence front-loads trigger conditions and user intents; the second states the exact return scope and grouping. Every part earns its place.

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 zero-parameter, read-only tool with no output schema, the description fully explains what the user gets: next 60 days of expiries, grouping dimensions, venue coverage, and settlement prices. Nothing essential is missing for an agent to decide whether to call this 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?

There are zero parameters and the schema coverage is 100%, so the description does not need to explain parameter semantics. Baseline for zero-parameter tools is 4, and no additional parameter detail is required.

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 ('returns') and clearly identifies the resource: futures/options expiries and settlement prices. It also lists concrete user intents ('what futures or options expire soon', 'next quarterly expiry', 'how many contracts settle this week'), which distinguishes it from sibling tools focused on other data like options flow or open interest.

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 description explicitly tells when to call it by enumerating several query phrasings. It does not name alternatives or state when not to use it, but among the sibling tools none overlap with expiry/settlement functionality, so the usage context is clear.

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