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

Annotations already establish that the tool is read-only, idempotent, open-world, and non-destructive. The description adds useful context beyond that: the formula is returned with the numbers, values are current, and settlement-rate data is not included. No annotation contradiction is present.

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 short, front-loaded with the main purpose, and avoids repetition. The second sentence is slightly dense with domain jargon such as 'builder running the table offline,' but it still earns its place by clarifying the return and alternatives.

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?

The output schema and annotations cover return shape and safety profile, so the description does not need to repeat them. However, for a four-required-parameter query tool with zero schema description coverage, the lack of parameter guidance leaves a material completeness gap.

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 0% for four required parameters, and the description does not explain any of them (asset, window_minutes, strike, minutes_left). It mentions returned fields rather than input semantics, providing only broad domain framing rather than parameter-level compensation.

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 states that the tool reports where a contract sits in the table's coordinates and enumerates the returned values (spot, sigma_1m, z, bucket). It also distinguishes this from get_rate_table and get_settlement_rate by explicitly excluding settlement rates, though the name get_z itself is not fully self-explanatory.

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 gives a clear usage context for a builder running the table offline against Kalshi's feed and explicitly routes settlement-rate needs to get_rate_table and get_settlement_rate. It does not cover every sibling (for example get_live_board), but the main alternatives are named.

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