plan_client_billing

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds behavioral context by emphasizing 'no-write' and 'next safe live check', reinforcing safety and the specific planning behavior. It does not contradict annotations and provides useful extra context beyond them.

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 well-constructed sentence that front-loads the verb and core purpose, with no wasted words. It efficiently covers both the plan construction and the output of the next safe check.

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?

The description gives a clear overview of what the tool does and its safety profile, and with annotations covering the read-only nature, it is reasonably complete for a high-level understanding. However, it lacks parameter explanations and does not clarify how it differs from sibling planning tools like prepare_interim_split or prepare_job_allocation, nor does it describe the plan's structure or return value in the absence of an output schema.

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 must compensate for parameter meaning, but it does not explicitly explain client_id, target_month, target_year, or invoice_key. The phrase 'client/Xero/allocation information' only vaguely hints at client_id and possibly invoice_key, leaving target month/year unaddressed. This is minimal compensation at best.

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 with a specific verb 'Build' and resource 'no-write billing plan', and adds a distinct output 'identify the next safe live check'. This distinguishes it from sibling tools like prepare_direct_invoice or execute_confirmed_action by emphasizing it is planning-only and does not write.

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 conveys clear context: it builds a plan and identifies a safe next step, implying it should be used before executing write actions. However, it does not explicitly name alternatives or state when not to use this tool, so it falls short of a 5.

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