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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains what happens when the threshold is reached ('it settles immediately instead of waiting for the periodic safety-net sweep'), and clarifies the effect of amount <= 0 ('clear your override and fall back to the platform default'). This is meaningful behavioral context beyond a simple setter. The only minor gap is the lack of information about return values or confirmation, but for a one-parameter mutation, this is acceptable.

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, but every phrase earns its place. The first sentence packs essential context: the action, the condition, the behavior, and the rationale (avoiding transaction fees). The second sentence clearly and concisely explains the override clearing behavior. There is no redundancy or filler; it is highly efficient while remaining readable.

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?

Given the tool's simplicity (one required parameter, no output schema, no annotations), the description is remarkably complete. It explains what the tool does, when to use it, how the threshold behaves, and how to clear it. It also provides the strategic context of fee avoidance, which is sufficient for an agent to select and invoke the tool appropriately in the broader payment system.

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 input schema already covers the parameter ('Settlement threshold in the platform's currency unit. <= 0 clears your override'), giving baseline 3. The description adds extra meaning by explaining how the threshold triggers settlement ('once your accrued micro-payment debt reaches this amount') and the purpose of batching, which helps the agent understand the semantics of 'amount' beyond the schema's dry description. This pushes it above baseline to 4.

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 clearly states the tool's function: 'Sets your (the calling agent's) micro-payment settlement threshold.' It uses a specific verb ('Sets') and a distinct resource ('micro-payment settlement threshold'), making it easy to distinguish from sibling tools like wallet_get_autopay_threshold (which reads the threshold) and wallet_get_balance (which reads balance). The detailed explanation of why this threshold matters further anchors its purpose.

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 provides clear context on when to use the tool: 'this is how two agents transacting in tiny increments avoid paying real-payment transaction fees on every micro-payment, by batching many into one settlement.' It also explains the behavior for positive values and the clearing behavior for <= 0. However, it does not explicitly name alternative tools or state 'use this instead of X,' though the context strongly implies the use case.

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