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

Annotations already mark the tool as destructive and non-idempotent, so the description’s key added value is disclosing the financial side effect: charging the shared account wallet. It does not state charge timing, amount, proration, or reversibility, but the main behavioral consequence beyond annotations is surfaced.

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 short sentences, front-loads the action and side effect, and contains no filler. The parameter sentence is brief even if it largely mirrors the schema enum.

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 one-parameter mutation tool with rich annotations and no output schema, this covers the core action, the wallet-charge consequence, and the accepted tier values. It omits billing details such as proration or charge amount, which would be useful for a financially destructive operation.

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 0%, so the description should compensate by explaining parameter meaning. Instead, it only restates the enum values already present in the schema ('plan_tier is pro or business') and adds no information about tier differences, billing impact, or selection guidance.

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 states a specific action and resource: moving the connected user to Pro or Business and charging the shared account wallet. This is clear enough to distinguish it from list_plans or explain_charges, though it does not explicitly name or contrast those siblings.

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 implies an upgrade action but gives no explicit when-to-use guidance, prerequisites, or alternatives such as checking list_plans or explain_charges first. The agent must infer usage entirely from the tool name and description.

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