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

Annotations already declare readOnlyHint=true, so safety is covered, and the description adds a genuinely useful non-obvious trait: 'Amounts are in cents.' That unit detail is not in the schema or annotations. It still omits pagination behavior and result shape, which keeps it short of a 5.

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 purpose and filters in one dense sentence, then two short trailing fragments for the unit and the upstream endpoint. Nothing is wasted, though 'Housecall Pro: GET /invoices' carries little actionable value for an agent.

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 13-parameter read-only list tool with no output schema, the description covers scope, the filter dimensions, and the amount unit. The main remaining gap is pagination behavior (page/page_size exist but are only described in the schema), which is a minor omission.

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 all 13 parameters are already documented in the schema; the baseline of 3 applies. The description adds the cents unit and summarizes filter categories but no syntax, defaults, or interaction details beyond the schema.

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 ('List') and resource ('invoices') plus a scope qualifier ('across the company') that meaningfully separates it from the job-scoped sibling housecall_list_job_invoices. It does not name that sibling outright, so the distinction is inferable rather than explicit.

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?

The concrete example 'everything open and overdue' anchors a real use case and the filter list implies when the tool applies, but there is no explicit when-to-use guidance and no mention of when to prefer housecall_list_job_invoices instead. Usage is implied rather than directed.

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