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

Beyond the readOnlyHint/destructiveHint annotations, it discloses that no message is sent, that it consumes the same monthly AI-processed-conversation quota as a real generation, and that output is an approximation with different fine-tuning than the UI button. The quota note is a genuinely useful behavioral trait not captured by any annotation.

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?

Front-loaded with the critical constraint 'AUCUN MESSAGE N'EST ENVOYÉ' in caps, followed by two tight sentences covering behavior, caveat, and cost. Every sentence earns its place 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?

For a single-parameter, read-only, non-open-world tool with no output schema, the description covers what it does, that nothing is sent, the approximation caveat, and the quota cost. 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?

There is a single parameter (conversation_id) with 100% schema description coverage, so the schema already carries the semantics. The description adds no format, scope, or validity detail beyond what the schema provides, matching the baseline 3 for fully-documented params.

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 states a specific verb (simulate/render for review) and resource (a reply on a conversation) and explicitly differentiates from real sending with 'AUCUN MESSAGE N'EST ENVOYÉ'. It also distinguishes itself from the UI 'Suggérer' button, so an agent can tell it apart from siblings like ficiel_send_message.

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 clearly frames the context — use this to preview text for review only, nothing is dispatched — which implies the alternative (real send tools). However, it never names a sibling (e.g. ficiel_send_message) or states an explicit when-not-to-use condition, so routing is inferred rather than spelled out.

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