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

With no annotations, the description carries the full burden of behavioral disclosure. It does not state whether this is a read-only operation, whether it requires specific permissions beyond authentication, or how pagination works despite having limit/offset parameters. It also does not mention that the auth_token and other_user_id are required, though that is evident from the schema.

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 a single, efficient sentence that is front-loaded with the core action. It avoids unnecessary detail, though it could benefit from clarifying the distinction from the plural sibling tool.

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?

Given that there are four parameters (two required, two undocumented), no annotations, and an output schema exists, the description is incomplete. It does not cover pagination behavior, authentication requirements beyond the parameter existence, or the format of the returned messages. It should provide more context for correct invocation.

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 0%, so the description must compensate. It mentions 'utilisateur authentifié' and 'un autre utilisateur', which maps to auth_token and other_user_id, but it does not explain the limit and offset parameters at all. With four parameters and no schema descriptions, this leaves significant gaps.

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 clear verb (Liste) and resource (messages exchanged between authenticated user and another user), which is more specific than the name alone. However, it does not distinguish itself from the sibling tool 'mcp_list_conversations' (plural), which likely lists conversation threads rather than messages. This ambiguity reduces clarity.

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?

No guidance is provided on when to use this tool versus alternatives. It does not explain when to choose listing messages over listing conversations, nor does it mention prerequisites like authentication. The description only states what it does, not when to use it.

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