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

Annotations already declare idempotentHint=true and destructiveHint=false, but the description adds real context: it states the operation is reversible, sends no message, deletes nothing, requires 'write' scope, and returns an 'already_in_state' marker on no-op. That is useful behavioral disclosure beyond the structured fields, short only of return-format details.

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?

Four short sentences, front-loaded with the action and followed by scope, side-effect guarantees, and the no-op case. No padding, though 'comme dans l'interface' is the least informative clause.

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 one-parameter mutation tool with no output schema, the description covers the safety profile, reversibility, required scope, and the notable already_in_state response. An agent has what it needs to call this correctly; only the response shape is left implicit.

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 tells the agent exactly what to supply. The description adds nothing about the identifier format, which is the baseline expectation when the schema does the work.

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: putting a conversation back into the unread state, and clarifies the scope covers both one-to-one and group conversations. It does not explicitly name the sibling ficiel_mark_conversation_read as its counterpart, though the name pairing makes the inverse operation discoverable.

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?

Usage is implied by the description of the operation, and the note about 'already_in_state' tells the agent what happens when the precondition is not met. There is no explicit statement of when to prefer this over alternatives such as ficiel_mark_conversation_read or ficiel_pin_conversation.

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