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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds genuinely useful context beyond them: what an inventory adjustment record represents (changes quantity on hand, books the valuation difference) and a hard eligibility constraint that US companies must be on Plus or Advanced — the kind of prerequisite an agent cannot infer from structured fields.

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 sentences, front-loaded with the action and retrieval key, with qualifying conditions following. Efficient overall, though 'when no search or write answer already holds it' is wordy for the guidance it conveys.

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 single-record getter with no output schema, the description supplies the record's business meaning and a platform/edition restriction, which is what an agent needs to decide whether the call can succeed. Return-value structure is reasonably left to the API, so remaining gaps are minor.

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% with only two parameters, both documented in the schema (the QuickBooks Id and the optional company selector). The description adds no format, resolution order, or multi-company guidance beyond what the schema already says, so the baseline 3 applies.

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 with the retrieval key ('Get a single inventory adjustment ... by Id'), and names the product (QuickBooks Online). It is clearly distinguished from create/update/delete_inventory_adjustment siblings as the read-one variant, though it never names a sibling search tool explicitly.

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 'when no search or write answer already holds it' gestures at when to prefer this over alternatives, but it is oblique — it does not name a specific alternative tool or state a clear condition, such as 'use search_ instead when you don't have the Id.' Usage is implied rather than spelled out.

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