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

The description says the tool can 'end' and 'rotate' a key, which conflicts with annotations declaring destructiveHint=false and idempotentHint=true. Ending or rotating a key is not merely additive and is generally not idempotent, so the behavioral description contradicts the structured safety hints.

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 a single compact sentence with the main action front-loaded and no wasted prose. The dense parenthetical is efficient, though it leaves important details implicit.

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 mutating tool with a nested object parameter and zero schema description coverage, the definition is too sparse. It omits the required payload structure, key-selection semantics for rotate/end, and any permission or failure behavior, leaving the agent unable to invoke it reliably.

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?

The schema exposes only an opaque required 'object' parameter with 0% description coverage, and the description does not explain what fields that object must contain. It mentions 'kind m2m-arena/delegation/v1', expiry, and active-key limits, but does not map these constraints to the parameter payload.

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 names a specific resource (signal key) and clearly states three operations: delegate, rotate, and end. It is more informative than the tool name alone, but it does not explicitly differentiate itself from related siblings such as publish_signal.

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 lists operations but gives no guidance on when to choose delegate versus rotate versus end, nor when to use this tool instead of siblings like publish_signal. The constraints about expiry and active keys are useful but do not constitute usage guidance.

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