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

Annotations already declare a safe, closed read (readOnlyHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description still adds real value by disclosing the return shape — an itemized, line-by-line breakdown where each line names its fee — which matters given there is no output schema.

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?

A single well-formed sentence with no filler, and the core output concept ('up-front total ... line by line') is front-loaded. It is slightly dense as a verbless noun phrase but wastes nothing.

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 read-only calculator with no output schema, the definition covers inputs and result shape but omits two things an agent would want: what 'up-front' actually bundles (deposit, registration, first month?) and the role of the month parameter on pricing. Adequate but with clear gaps.

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 100%, so all four parameters including the YYYY-MM month default and comma-separated subject ordering are already documented. The description only echoes branch/level/subjects and says nothing about the month parameter, which plausibly changes the total, so it does not exceed the schema baseline.

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 computable output — the up-front total for a child starting given subjects at a branch and level — which is clearly distinct from generic fee siblings like get_fee or query_fees. It is clear but never explicitly contrasts itself with those fee-lookup tools, leaving the differentiation to inference.

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 phrase 'a child starting these subjects' implies the onboarding/enrolment scenario, but there is no explicit when-to-use guidance, no statement of when to prefer this over get_fee or query_fees, and no prerequisites mentioned. Usage is only inferable from the scenario wording.

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