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

Annotations already establish readOnly, idempotent, non-destructive, closed-world behavior. The description adds useful beyond-annotation context by listing the specific review data read and including a prompt-injection safety note that document contents are data, not action instructions. It does not describe response shape or sequencing, but the key behavioral traits are covered.

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 two short sentences with the core purpose front-loaded. Every sentence contributes either scope information or a valuable safety constraint, with no wasted text.

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 single-invoice review tool with no output schema, the description sufficiently states what data is inspected and why it exists. The main remaining gap is that it does not clarify how to obtain a valid invoice_id or distinguish the tool from adjacent read tools.

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?

The schema has one required parameter with 0% description coverage, so the description must compensate. It only implies that an invoice is being read and does not explain the invoice_id format, source, or constraints beyond what the schema's property name conveys, but with a single obvious identifier parameter this is minimally adequate.

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 uses a specific verb ('Read') and names the exact invoice facets it returns: validation flags, math checks, saved lines, and approval state. It clearly scopes the tool to explaining what needs review, though it does not explicitly contrast itself with siblings like get_invoice or get_review_queue.

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 intended use is implied by 'to explain what needs review,' giving an agent a reasonable context for selection. However, there is no explicit when-to-use guidance, no when-not-to-use guidance, and no naming of alternatives such as get_invoice or check_invoice.

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