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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds the authentication requirement (Bearer mccf_ token), which is genuinely useful context, but the credential string trails off with '...' and nothing is said about result size or pagination.

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 compact sentence that front-loads the audience and the returned data. The dangling '...' in the credential is the one piece of sloppiness that keeps it from being tight.

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 input parameters and no output schema, the description carries the burden of describing the return value, and it does so at a field level. What is missing is volume behavior (how many invoices, ordering) for a list-style read.

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?

The tool takes zero parameters, so the baseline is 4; there is no parameter meaning the description needs to carry. It does note the auth header, which is adjacent to calling convention rather than a schema field.

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 the resource (the firm's invoices) and the fields returned (status, due date, pay link), so an agent knows exactly what it gets. It lacks an explicit verb and never contrasts itself with siblings like firm_orders, but the scope is unmistakable.

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?

Usage is gated by a stated precondition – an approved MCC business account's assistant – which implicitly tells the agent when this tool applies. There is no explicit when-not-to-use guidance or reference to an alternative for order-level detail.

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