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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuine behavioral value by disclosing the returned data shape ('one amount per account per period'), which matters because no output schema exists, though it says nothing about not-found behavior or errors.

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 short sentences, zero waste, front-loaded with the core verb and resource before the usage caveat and the return-shape note.

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 lookup with no output schema, the description supplies the entity identity and the essential shape of the result, and the annotations cover safety. It could go slightly further on failure modes (e.g. invalid or unknown Id), but an agent has enough to call it correctly.

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, so the schema fully documents 'id' and 'company'. The description adds no additional semantics such as Id format or multi-company disambiguation rules, so the baseline 3 is appropriate.

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 names a specific verb and resource ('Get a single budget from QuickBooks Online by Id') and qualifies the entity type ('A profit-and-loss budget with one amount per account per period'), which separates it from report-style siblings like get_budget_vs_actuals and list-style siblings like search_budgets.

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?

It states a usage condition: use this 'when no search or write answer already holds it,' which clearly implies retrievals obtained via search_budgets or a create/update response should take precedence. It stops short of naming those sibling tools explicitly, which would have made routing indisputable.

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