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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds domain context beyond annotations: it is 'an accounting record of a bank payment toward a credit card balance' and 'does not move money,' which prevents confusion with an actual payment operation.

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?

Three short sentences with no wasted words. The core purpose and usage condition are front-loaded in the first sentence, followed by concise domain and negative clarification.

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 read-by-Id tool with full parameter coverage, safety annotations, and no output schema, the description is complete enough to call correctly. It covers purpose, scope, usage condition, domain meaning, and the key negative behavior.

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 the schema already documents both the required 'id' and optional 'company' parameters. The description only specifies lookup by Id and adds no syntax, format, or company-selection guidance beyond what the schema provides.

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 ('Get a single credit card payment txn from QuickBooks Online by Id') and scopes it to a single record. The phrase 'when no search or write answer already holds it' distinguishes it from search and write siblings without requiring the agent to open a schema.

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?

Gives a clear usage condition: use it when no search or write answer already holds the record. This implicitly routes the agent away from search_credit_card_payment_txns and create/update/delete siblings, though it does not name them explicitly.

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