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

Annotations already establish readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds substantive behavioral context beyond that: it names the five SARS/court factors the reasoning weighs and explicitly frames the result as a heuristic indicator rather than a ruling, which shapes how the agent should present and trust the output.

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, both load-bearing: the first defines the answer and its tax consequences, the second lists the deciding factors and bounds the reliability of the result. The caveat is placed where it matters, at the end, with no filler.

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 no output schema, the description must convey what comes back, and it does: a reasoned indication along a capital/revenue spectrum with a stated tax consequence on each side. For a six-parameter advisory tool with safety annotations already in place, this is close to complete; only pagination-style operational details are absent, and they do not apply.

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 the baseline is 3. The description still earns credit by explaining why these inputs matter — intention, holding period, trading frequency, funding and business-like operation are the factors SARS and the courts weigh — giving the agent a rationale for populating each field rather than treating them as arbitrary switches.

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 classification task: deciding whether a South African taxpayer's crypto gains are capital (CGT, 40% inclusion) or revenue (income). That is a clear verb-plus-resource, and the jurisprudential framing separates it in spirit from the numeric siblings. It never names those siblings, so there is no explicit routing.

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 closing caveat 'An indicator for discussion, not a ruling' tells the agent this is advisory output rather than a definitive computation, which is real usage context. It does not say when to call this instead of crypto_tax_estimate or crypto_tax_rules, so selection still relies on inference from the sibling names.

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