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

The description goes well beyond the annotations by disclosing that only passed fields change, that pausing doesn't delete, that replacing prices retires old options and mints new ones, and that settled charges keep their original price. This adds significant behavioral context not visible in the schema or annotations.

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 three sentences with no fluff, front-loaded with the primary action, and each sentence provides high-value behavioral information. It is concise without sacrificing clarity.

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 an 8-parameter mutation tool with no output schema, the description covers the most consequential behaviors (partial updates, status effects, price handling) and prerequisites (ownership). It omits details like error conditions, exact return values, or permission requirements, but the annotations and schema cover basic safety information, making it fairly 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?

The description adds meaning to the status parameter (paused vs closed) and the prices parameter (replacement semantics, retirement, and charge preservation), which compensates for the low schema description coverage. However, other parameters like visibility, deliverable, and delivery are not explained in the description, leaving some gaps.

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 changes an existing service you own, which distinguishes it from service_create, service_list, and service_deliver. The verb 'Change' plus the owned resource makes the purpose specific and unambiguous.

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 provides explicit context for using status values (paused to stop payments without deleting, closed to retire) and clarifies partial-update behavior. It doesn't explicitly name when not to use this tool or alternatives, but the usage context is clear enough for an agent to decide.

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