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

Annotations already declare this a safe, deterministic, non-destructive read (readOnlyHint, idempotentHint, openWorldHint=false), so the safety profile is covered. The description adds that it returns a net result under each regime, but says nothing about the modeling assumptions (e.g. amortization under IS) or limitations an agent might need to set expectations.

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?

Four short sentences, front-loaded with purpose, then audience, then inputs, then the cross-reference. Nothing is redundant filler and each sentence carries information the agent can act on.

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 an output schema present and 100% parameter coverage, the description does not need to explain return values, and it correctly avoids doing so. It is essentially complete for a pure calculator, though a note on the French regime assumptions would have made it fully self-sufficient.

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 100%, so all four parameters are already documented in the schema with units and ranges. The description's recap ('rental income, charges, owner tax bracket') adds no syntax, format, or edge-case meaning beyond that baseline.

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 (compare) plus a precise resource (SCI taxation under IS vs IR) and the domain audience (French real-estate investors). No sibling in the list covers this comparison, so the agent can identify it unambiguously from the name and description alone.

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?

'Use for French real-estate investors choosing tax regime' gives a clear decision context, and the closing pointer to list_bundles routes the agent to related 'immobilier' calculators. It stops short of naming explicit alternatives or when-not-to-use cases among the many calculate_* tax siblings.

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