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

Adds substantial behavior beyond the annotations: stage transitions to 'RDV pris' only if the contact was before that step, contacts already no-show/signed/lost keep their stage with only the date updated, the action is journalized and counts in the flow, and no message is sent. This complements destructiveHint/idempotentHint with concrete semantics rather than repeating them.

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 core verb and resource, then layers stage behavior and the no-message caveat. It is dense but each clause carries information; only the stage-exception parenthetical is slightly heavy.

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 2-parameter mutation tool with full schema coverage and annotations covering the safety profile, the description supplies the remaining needed context — stage-transition rules, journaling, absence of messaging, and required scope. No output schema exists, so return values need not be explained.

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 both parameters (lead_id, appointment_at with ISO 8601 format) are already documented. The description reinforces that the real date/time is written to the card but adds no syntax or format detail beyond the schema; baseline 3 is appropriate.

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?

States a specific verb and resource — recording that an appointment was booked with a contact — and clarifies it is done 'hors de Ficiel' (external agenda/CRM), which pins down the exact intent versus siblings like ficiel_book_slot. An agent can identify the right tool without opening the schema.

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?

Gives clear context: it records an already-taken external appointment, and explicitly routes message confirmation to ficiel_send_message ('N'envoie aucun message'). It also states the required 'write' scope. It stops short of explicitly contrasting with ficiel_book_slot or ficiel_set_stage, but the 'hors de Ficiel' framing makes the distinction inferable.

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