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

Annotations already cover the safety profile (readOnly/openWorld/non-destructive), and the description adds real behavioral context beyond that: sort order (newest first), computed-field semantics (balance due = total minus amount paid; retainage held listed separately), page size (up to 100), and the auth requirement (Cotlet API key with app access). That is meaningful disclosure the annotations don't provide.

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 the returned-field list and scoping/sort info before the filter and auth notes. Every sentence is relevant, though the computed-field explanations edge toward detail that a return-value doc might carry.

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 carries the burden of explaining returns, and it does so well (fields, sort order, computed balances, pagination). Auth requirement is noted. Only lacking is explicit routing against alternatives, but for a straightforward list tool this is nearly complete.

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 all four params. The description restates the filter semantics ('with a balance', 'due before a date') but adds no syntax or format detail beyond the schema. 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 the resource (invoices) and enumerates the exact fields returned (project, customer, total, amount paid, balance due, retainage held), so the agent knows precisely what this returns. It doesn't explicitly differentiate from siblings, though no close sibling exists within the contractor-foreman family.

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?

Filtering guidance is implied ('Filter to invoices with a balance or due before a date'), which maps to the unpaid_only and due_before params. However there is no explicit when-to-use/when-not-to-use framing or reference to an alternative tool, leaving the agent to infer the conditions.

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