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). The description adds value beyond that with a redundancy-avoidance rule — don't spend a call if a search or write already returned the memo — which is genuine behavioral context. It does not mention not-found/error behavior or what the returned memo contains.

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?

A single sentence with the action, resource, keying parameter, and usage condition front-loaded. No filler.

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 simple single-record read with a fully documented two-parameter schema and annotations, the description is nearly sufficient. The remaining gap is reporting what happens on an unknown Id or ambiguous company, which an agent would want before calling.

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%, so both 'id' and 'company' are already documented in the schema; the description only restates 'by Id' and says nothing about the optional company selector. Baseline 3 is appropriate when the schema carries the parameter burden.

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 retrieval scope: 'Get a single credit memo from QuickBooks Online by Id.' The word 'single' implicitly separates it from search_credit_memos, but the sibling is never named, so the differentiation is left to inference.

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?

Provides a real when-to-use condition: only fetch when a search or write response doesn't already contain the record. It stops short of naming search_credit_memos as the alternative path, so the routing is implied rather than explicit.

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