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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, so the safety profile is carried structurally; the description adds nothing about what a status change actually does, whether transitions are restricted (e.g. paid back to draft), or whether changes sync downstream. For a destructive, non-idempotent mutation, that is a real gap.

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?

One sentence, front-loaded with the verb and resource, with no filler. It is efficient but borders on over-terse given the mutation risk involved.

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?

A five-parameter destructive mutation with 20% schema coverage, no output schema, and no annotations-level context supplied in the description leaves the agent without the details it needs — partial-update semantics, status transition rules, and side effects are all absent.

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 20% (just invoice_id carries 'From list_invoices'), but the description compensates partly by naming the four other parameters and their purpose. It adds no detail on status transition validity or what clearing a field means, so it hovers at a minimum-viable level.

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 (changes) and resource (invoice) plus the four mutable fields, which cleanly separates it from create_invoice, delete_invoice and send_invoice. It does not explicitly distinguish itself from sibling status-only updaters like update_service_ticket_status, but the field list makes the scope clear.

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?

There is no guidance on when to use this versus delete_invoice, send_invoice, or list_invoices, and no mention that only invoice_id is required while the other four fields are optional partial updates. The agent must infer usage entirely from the field list.

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