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

Annotations already flag destructiveHint=true, and the description earns its keep by adding the live consequence: 'Live sends over the cap are refused.' It still doesn't say what removing the cap entails (unbounded spend) or that the change is non-idempotent.

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?

Two compact sentences, front-loaded with the action and immediately followed by the operational consequence. 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?

For a destructive, non-idempotent mutation with no output schema, the description covers the enforcement effect but omits what state changes on removal and the threshold semantics. Adequate but with clear gaps an agent would want filled.

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 coverage is only 50%, and the undocumented parameter is alert_thresholds — the description mentions 'alert thresholds' but never says they are percentages, up to five, or how they relate to the cap. Only the cap parameter gets contextual meaning (removal), leaving the agent to infer the rest from constraints.

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 specific verb and resource ('set or remove the monthly spend cap and its alert thresholds'), which cleanly separates it from get_spend_limit. It doesn't name the sibling explicitly, but the mutation framing makes the contrast obvious.

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 'set or remove' phrasing implies the two usage modes, and 'null removes the cap' ties to the schema. However, there is no guidance on prerequisites, permissions, or when an agent should clear a cap versus lower it, and no named alternative.

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