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

Annotations already indicate readOnlyHint=true, so the description doesn't need to state that. However, it adds the specific tax rates and the note about assurance-vie, but it doesn't disclose what the output looks like, any precision/rounding behavior, or edge cases (e.g., negative gains). Given the description carries full burden in the absence of output schema, this is a gap.

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 with the key information (rates, total percentage, and the reference to assurance-vie). It's efficient and front-loads the tax rate, though the note about assurance-vie is vague.

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 simple calculation tool with one parameter, it's relatively complete, but lacks clarity on the output format, any units for gains, and the exact handling of assurance-vie (which might be an alternative tax regime). The description could be more precise about what the calculation includes or excludes.

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 0%, so the description must explain the parameter 'gains'. It mentions 'sur des gains' but does not describe the expected format (number in euros? percentage? currency?) or any constraints (minimum, maximum). This adds some meaning but incomplete.

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 clearly states the function: calculating PFU 2026 on gains with a specific tax rate breakdown. It identifies the resource (gains) and the tax regime (PFU), but does not explicitly contrast with sibling tools like simuler_interets_composes, though the intent is distinguishable.

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 does not specify when to use this tool versus others. It mentions 'fiscalité assurance-vie en note' but that seems to be a note, not a routing instruction. No explicit context or exclusions are provided.

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