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

Beyond the annotations (readOnly, idempotent, non-destructive), the description discloses concrete behavioral traits: images are resized to max 1568px, documents capped at 10MB, videos are never transmitted, and the response includes previously extracted text in full. These are operationally significant details the annotations do not carry.

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 description is front-loaded with the core behavior and then layers constraints (size caps, video exclusion) and provenance in a compact sequence. It is slightly dense but each clause carries distinct information, 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?

There is no output schema, yet the description compensates by describing what comes back (image, embedded file, extracted text in full). For a single-parameter read tool with annotations already covering safety, nothing an agent needs 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?

With 100% schema coverage the baseline is 3, but the description adds real value by explaining where message_id originates (the 'media' field of a message from conversation, lead context, or search endpoints). That provenance guidance exceeds what the schema's 'Identifiant du message qui porte le média' conveys.

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 and resource ('Rend l'ORIGINAL d'un média d'une conversation') and immediately clarifies the goal ('pour le voir vous-même'). It also scopes the tool by excluding video, so an agent can tell exactly what it fetches versus what it does not.

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 explicitly names the prerequisite tools that produce message_id (ficiel_get_conversation, ficiel_get_lead_context, ficiel_search, media field), which gives clear routing context. It does not, however, contrast itself with adjacent media tools like ficiel_send_media or explain when retrieval is unnecessary.

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