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

Annotations already declare the safety profile (destructiveHint=true, idempotentHint=true), so the bar is lower. The description adds genuinely useful behavioral context — that approved_amount silently defaults to the invoice total and that a lower value constitutes a short-pay — which is not derivable from structured fields, though it omits any warning about the destructive/irreversible nature of the action.

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?

Two tightly written sentences with zero padding, and the core action is front-loaded ahead of the parameter detail. Every clause earns its place.

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 mutation tool with destructiveHint=true and no output schema, the definition covers the essential parameter behavior but omits the note parameter, any permission or state prerequisites, and any indication of what approval triggers downstream. Given the 0% schema coverage, it is adequate but leaves 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 0%, so the description carries the full burden. It competently explains the most ambiguous parameter (approved_amount's default and short-pay semantics) but says nothing about note, leaving one of three parameters completely undocumented.

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 ("Approve an invoice"), which is unambiguous on its own. However, it never differentiates itself from the very similar siblings reject_invoice, hold_invoice, and dispute_invoice, so the agent must infer which action applies from the name alone.

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?

No when-to-use guidance and no alternatives named. The description never says when approval is appropriate versus rejection, holding, or disputing an invoice, nor what prerequisites (e.g. matched PO, no open exception) must exist first.

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