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

With no annotations, the description carries the full burden and does well: it discloses pricing semantics (signed rate, cost plus markup), a hard stop at the not-to-exceed amount plus approved change orders, the needs_change_order signal, and that the result is a draft. It omits behavior around duplicate invoices for the same quote and what happens with unsigned quotes or zero billable time.

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 tight sentences, front-loaded with the core billing rule, then the cap/stop condition, then the draft-and-permissions caveat. No filler and no repetition of schema or annotation data.

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?

An output schema exists so return values need not be explained, and the description covers the billing logic, cap behavior, draft state, follow-up tool, and authorization. The remaining gap is parameter-level guidance for due_on, memo, and the rush-rate entries, which an agent would have to infer.

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 25%: only rush_entry_ids is documented in the schema, and due_on and memo are undocumented anywhere. The description explains the billing math but never names quote_id, due_on, memo, or even the rush-rate path that rush_entry_ids enables, so it does not compensate for the coverage gap.

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 a specific verb and resource: bill a signed time-and-materials quote, billing unbilled approved time at the signed rate and materials at cost plus markup. It is clearly distinct from a generic invoices_create, though it never names its closest sibling invoices_createFromQuote, so the differentiation is implied rather than stated.

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?

It gives a clear workflow handoff ("Draft; send it with invoices.send") and names the caller restriction ("Owner or office with see_costs only"), which effectively tells an agent when it may use it. It does not explicitly state when to prefer invoices_createFromQuote over this tool, so it falls short of full alternative routing.

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