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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds two useful non-annotation facts: issued invoices are locked in Houzz Pro, and a Cotlet API key with app access is required. It still says nothing about pagination or result limits.

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 are near-duplicates, both listing code/total/status/payments received, which wastes space. It is front-loaded and short, but the redundancy prevents a higher score.

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 one-parameter list tool with no output schema, the description usefully describes the returned fields and the locking behavior of issued invoices. However, it omits pagination/volume behavior that matters for a list endpoint, leaving a clear gap.

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% and the single project_id parameter is documented as coming from list_projects, so the schema carries the load. The description only restates that invoices are scoped to 'one project' without adding format or constraint detail, matching the baseline 3.

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 states a specific verb and resource ('returns the invoices of one project') and enumerates the returned fields (code, total, status, payments received), which distinguishes it from the sibling create_invoice. It doesn't explicitly name or differentiate against other read siblings, so it stops short of a 5.

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 only implied: an agent can infer this is the read path for a given project, and the schema note points to list_projects for the ID. There is no explicit when-to-use/when-not guidance or named alternatives among the many list_invoices-style siblings across apps.

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