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

With no annotations, the description carries the behavioral burden. It communicates that the tool concerns a legal language mention and suggests simple textual output, but it does not disclose the exact return value or side effects. The 'Paid $0.01 USDC Base x402' sentence adds unrelated noise rather than behavioral clarity.

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?

The first sentence is compact and front-loaded with the legal context. The second sentence about payment is unexplained and not obviously relevant to the tool's purpose, making the description less crisp than it should be.

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, parameterless legal mention tool, the description gives enough legal context to infer when the mention is used. However, without an output schema or an explicit statement of what the tool returns, an agent still has to infer the exact behavior.

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?

There are no declared parameters, so the schema provides no parameter burden and the baseline is 4. The description does not need to explain parameter semantics for this zero-parameter tool.

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 identifies the tool as a 'French invoice language mention' and adds legal context (Toubon 94-665, B2C vs B2B), which helps distinguish it from the many other French invoice mention siblings. It does not use an explicit verb such as 'returns' or 'generates,' but the noun-phrase framing is clear enough.

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?

It offers conditional context: Toubon applies to B2C in France, while B2B defaults to French for tax control. This implies when the mention is relevant, but it does not explicitly state 'use this tool when...' or name alternative tools.

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