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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description goes further by disclosing the computational model: a flat 50% inclusion rate, principal-residence exemption, LCGE for QSBC shares, capital-loss offsets, rental CCA recapture, and stacking on other income at federal + provincial brackets. 'Estimate' honestly signals an approximation rather than a filed figure.

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?

Two sentences, front-loaded with the action and scope, and the methodology list is compact rather than padded. It is dense but every clause carries information; only the long exemption enumeration risks being skimmed.

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 19-parameter tax engine with no output schema, the description gives an unusually complete picture of the calculation pipeline and the conditions each branch responds to. It omits how taxYear affects brackets and whether results break down by federal vs provincial components, which are the remaining gaps.

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 89%, so the schema already documents nearly every parameter, and the description mostly restates the same mechanisms (PRE, LCGE, CCA recapture) without naming parameters or adding input-format detail. The one genuinely additive point is that the gain stacks on top of other income, which clarifies the role of annualIncome.

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 — 'Estimate Canadian capital gains tax on a disposition' — and enumerates the covered asset classes (real estate, stocks, crypto, business, rental). That scope cleanly separates it from siblings like income_tax, land_transfer_tax, and bc_home_flipping_tax.

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 asset-type list implies when the tool applies, but there is no explicit when-to-use/when-not guidance and no routing to alternatives. With twelve siblings — including income_tax and bc_home_flipping_tax, which overlap on Canadian property taxation — the agent is left to infer which calculator to pick.

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