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

Annotations already declare a non-read-only, destructive, non-idempotent write, but the description adds genuinely new behavior: the mutual exclusivity of feeMinor and percent per basis, and the hard constraint that basis/grace/fee/percent cannot change after approval until a revise_late_terms suggestion is accepted. It stops short of stating permissions or what the write returns, so not a 5.

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?

Three dense sentences, front-loaded with the action and the field semantics, with no filler. The final sentence is long but carries a real constraint rather than padding.

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?

An output schema exists, so return values need not be described, and the description covers the mutation's semantics and its post-approval immutability rule. The remaining gap is the precondition for calling at all (which invoice states are writable) and the purpose of the note field.

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% across 6 required parameters, so the description must compensate. It does explain the basis enum meanings and the feeMinor vs percent coupling, but leaves graceDays, invoiceId, and note semantics (note is a required 1-1000 char justification) unaddressed.

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?

States a specific verb and resource ('Record late terms') and immediately enumerates the key fields (grace days, basis), including the three basis values. It is distinguishable from the read/calculate siblings, though it doesn't explicitly name a sibling it is not, which keeps it short of a 5.

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?

Usage is implied rather than stated: the agent learns a post-approval write is refused until an accepted revise_late_terms suggestion exists, which is useful lifecycle guidance. However, there is no explicit when-to-use/when-not framing, no statement of required invoice state, and no comparison to sibling tools like suggest_invoice_change.

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