update_billing_client

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

Annotations already indicate readOnlyHint=false (mutation) and destructiveHint=false (non-destructive). The description adds little beyond confirming it is an update operation. It does not disclose side effects, whether confirmation is required, or any impact on related records. The mention of 'whmcs/update_client' hints at an external API call but provides no additional behavioral detail.

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, concise sentence that front-loads the action and resource. It wastes no words and is easy to parse. While it could be structured with bullet points for clarity, it is appropriately sized for the information it conveys.

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 has 12 parameters, only one required, and no output schema, the description should provide more context about required fields, how to identify the client, and expected results. It does not mention the mandatory 'confirm' parameter or any success/failure behavior. The description is too sparse to fully guide an agent in invoking this tool correctly.

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 8% (only 'confirm' has a description). The description lists a few fields (ФИО, company, address, email, phone) but omits many parameters like city, state, country, postcode, address2. It uses 'etc.' which is vague and does not compensate for the lack of schema descriptions. The agent would be left guessing about the exact meaning of several parameters.

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 purpose: updating client data in the billing system (WHMCS). It specifies the resource (client) and the action (change), and lists example fields (ФИО, company, address, email, phone). It distinguishes from read-only siblings like get_billing_client by the verb 'change', though it does not explicitly differentiate from update_contact.

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 gives no guidance on when to use this tool versus alternatives like update_contact or reset_billing_password. It does not mention prerequisites (e.g., client identification) or context in which it is appropriate. The intended usage is only implied by the name and description, leaving the agent to infer when this is the right choice.

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