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

Annotations already cover read-only, idempotent, non-destructive and closed-world. The description adds non-obvious behavioral context beyond that: it produces no materials cost, no inferred VAT and no binding quote, and it does not modify WordPress or contact the company — useful expectation-setting for downstream agents.

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-loads what the tool opens and what price basis it uses, then moves through argument handling, the area_m2 warning, and the negative constraints. Dense and purposeful, though the run of short negated clauses ('No materials, no inferred VAT, no binding quote') reads as a list rather than flowing prose.

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 three optional params, no output schema and full annotation coverage, the description supplies what's needed: how to call it with and without arguments, the calculation basis for area, and the limits of the result. Only the preparation sub-object semantics remain solely in the schema.

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 67%, and the description compensates well on the risky parameter: area_m2 is the measured painted wall/ceiling surface, never floor area, and must not be derived with a multiplier. It also reinforces the single-finish constraint and independence of preparation areas, though it says nothing about the preparation enum values themselves.

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 and resource — 'Open an interactive painting labour calculator with current public Oleba price ranges' — which an agent can distinguish from a plain price lookup. It clarifies scope boundaries (no materials, no VAT, no binding quote, no WordPress edits, no company contact) but never names the sibling price tools (get_prices, get_price_information) it could be confused with, which keeps it below 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?

'Omit arguments to let the user fill it in' gives a clear default usage path, and 'One painting type per estimate; preparation areas are independent' tells the agent how to compose inputs. No explicit when-not or named-alternative guidance for the price-info siblings, so not a 5.

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