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

Annotations already establish readOnly/non-destructive, and the description adds valuable context: it discloses the auth prerequisite (a Cotlet API key with access to the app) and describes what the payload contains (payments recorded so far, client payment link), which enriches the safety-only annotation profile.

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?

The first two sentences largely restate the same field list ('line items... payments... payment link' then again 'its line items, payments... and the payment link'), which is redundant. The redundant 'SuiteDash:' prefix also consumes space without information.

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?

With no output schema, the description usefully carries the burden of describing return contents, and with annotations covering safety it adds the auth requirement. Complete enough for a single-parameter read tool, though it omits pagination or error behavior (not relevant here).

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% and the single invoice_id parameter is fully documented in the schema. The description adds no new semantics beyond what the schema already provides, so the baseline of 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 ('Get invoice') and enumerates the returned fields (line items, discounts, taxes, payments, notes, payment link). 'Returns one invoice' implicitly distinguishes it from the sibling list_invoices, but it never names that sibling 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?

Gives a concrete when-to-use rule: 'Read it before record_payment to check what is still owed,' which routes the agent into a workflow and references a sibling tool. It does not state when NOT to use it or name list_invoices as the bulk alternative, so it stops short of a 5.

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