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

Annotations already establish the safe read-only, idempotent profile, so the description's added value is the precision behavior: exact big integers for large results and disclosure that 'the rule used' is reported. That is meaningful context beyond the annotations, though it doesn't cover edge cases like domain errors for negative bases with fractional exponents.

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 well-packed sentence leads with the purpose and capability list, followed by a reference URL. No filler, no redundancy, and the most important information is front-loaded.

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 4-parameter, all-optional tool with no output schema, the description communicates what it computes, the input shapes it accepts, and a key output trait (exact integers, rule shown). Slightly more on the power/root mode distinction or error behavior would make it fully complete.

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 100%, so the schema already documents base, exp, n and the mode enum, and the description's examples (2/3 as a fraction, negative exponents) simply illustrate what the schema explains. Nothing parameter-specific is added, which is the correct baseline of 3 under full coverage.

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 clear verb+resource (exponent calculator) and enumerates concrete capabilities: negative, decimal and fractional powers plus nth roots, with worked examples (8^(2/3), 2⁻³, 2^100). It implicitly differentiates from square_root_calculator by covering general exponentiation, but never names or excludes sibling tools, keeping it short of a 5.

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?

There is no when-to-use guidance, no stated prerequisites, and no routing to alternatives such as square_root_calculator for pure roots or logarithm_calculator for inverse problems. The agent must infer that this tool is the general-purpose option from the description alone.

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