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

Annotations are limited to readOnlyHint=false, openWorldHint=true, destructiveHint=false, so the description carries the real burden and does so: partial amounts produce a partially paid invoice, send_confirmation emails the client, the default per-call confirmation can be disabled, and it explicitly warns that the action reaches other people and needs an API key with app access.

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?

Front-loaded with purpose and scoping, then behavior, then confirmation/auth constraints. Each sentence is useful, though 'Records a manual payment on one invoice' partly restates the opening sentence, which is minor redundancy.

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 five-parameter mutation tool with no output schema, the definition covers outcome semantics (partial payment), side effects (client email), confirmation policy, reach to other people, and auth requirements. Nothing an agent needs before calling is missing.

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 coverage is 100%, so the baseline is 3. The description still adds meaning beyond the schema by explaining the consequence of a partial amount, that payment_type comes from the user's account, and what send_confirmation triggers (the standard payment confirmation email).

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 ('Record a payment') and scopes it precisely: a payment made outside SuiteDash applied against an open invoice. That scope distinguishes it from invoice creation/listing siblings without the agent needing to open any 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?

The description gives clear context for when this tool applies ('payment made outside SuiteDash', 'against an open invoice', one invoice per call) rather than alternatives like creating an invoice. It does not explicitly name a sibling tool to use instead in other cases, so it stays short of a full routing instruction.

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