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

readOnlyHint=true already establishes the safety profile, so the description's main extra contribution is the underlying endpoint (GET /invoices), which quietly confirms it is a non-mutating read. It adds nothing about pagination, result volume, or whether the date defaults are applied server-side, leaving modest gaps for a read tool.

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?

Three short clauses, purpose front-loaded, no filler. The trailing 'API: GET /invoices' is marginally useful for developer-style consumers but is the least essential sentence.

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?

The tool is simple (4 optional params, no output schema, read-only) and the schema plus annotations fill most needs. However, with no output schema, the description should hint at the returned invoice shape or ordering, which it does not.

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%, including the important 'OPEN includes due and overdue' nuance, so the schema already carries the semantic load. The description restates the same filter dimensions without adding format or interaction details, which is the expected baseline.

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+resource ('List customer invoices') and enumerates the filter dimensions, so the agent knows exactly what it retrieves. The 'customer' qualifier implicitly separates it from runmyaccounts_list_vendor_invoices, but no sibling is named 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?

No guidance on when to use this versus runmyaccounts_get_invoice or runmyaccounts_list_invoice_payments, and no mention of defaults or preconditions beyond the filter list. The agent must infer the calling context from the name alone.

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