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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely useful behavior context beyond that: the failure outcome (loss of Qualifying Free Zone Person status for the period plus the next 4 periods) and the regulatory basis, which is exactly the kind of consequence an agent cannot infer from annotations.

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 tight sentences: the test criteria first, then the consequence. No filler, no restatement of the name, and the numeric threshold is front-loaded where an agent will read it.

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 two-number, read-only calculation the description covers the rule, the regulatory source, and the failure consequence. With no output schema present it could optionally say what the result contains (pass/fail, headroom), but nothing needed to invoke it correctly is missing.

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% with both parameters documented, including the nuance that nonQualifyingRevenue excludes disregarded revenue. The description adds no further parameter semantics, so the baseline of 3 is appropriate when the schema does the heavy lifting.

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?

Specific verb (test) and resource (free zone company's non-qualifying revenue against the de minimis limit), with the exact rule stated (lower of 5% of total revenue or AED 5m, MD 229 of 2025). No sibling tool overlaps this domain, so an agent can select it unambiguously.

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 description makes the triggering condition clear (a QFZP's non-qualifying revenue) and states the consequence of failure, which implicitly tells the agent when this test matters. It does not name any alternative tool or state when not to run it, but the siblings are unrelated domains so the gap is minor.

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