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

Annotations already declare a safe, read-only, closed-world calculation, so the burden is lower. The description does add genuinely useful behavior: commission rates come from province defaults but are overridable, and the output nets out the mortgage payoff. It does not describe the shape of the result (e.g., line-item breakdown vs single total), which matters given no output schema.

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?

One sentence, front-loaded with the outcome (total cost and what you walk away with), followed by the component chain. It is dense but every clause maps to a real parameter group; the parenthetical is the only slightly awkward element.

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 12-parameter calculator with only one required field and no output schema, the description covers all cost categories and the final net-proceeds step, so an agent can call it correctly with minimal input or with overrides. A brief note on what the response contains would close the remaining 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%, so every parameter is already documented, and the baseline of 3 applies. The parenthetical 'province starting rates, all overridable' and the ordered cost chain give the agent a mental model of how province, structure, and the rate overrides interact, but no individual parameter meaning is added 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?

The description states a specific verb and resource — computing total cost of selling a Canadian home and the net proceeds — and enumerates the cost components (commission + GST/HST, legal fees, discharge fee, other costs, mortgage payoff). This separates it in spirit from buyer-side tools like closing_costs and single-component tools like real_estate_commission, though it never names a sibling 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?

Usage is implied by 'selling a Canadian home,' which scopes it geographically and directionally, but there is no explicit when-to-use/when-not guidance or routing to related calculators (e.g., use real_estate_commission for commission alone, closing_costs for the buy side). The agent must infer the boundary.

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