Update mail user properties in ISPConfig by specifying the client, mail user ID, and fields to change.
Update a mailbox
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes | Fields to update | |
| user_id | Yes | Mail user ID | |
| client_id | Yes | Client ID |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure, yet it only conveys that a mutation occurs. It does not state whether params replaces or merges existing settings, whether changes are reversible, what side effects might occur on related objects (aliases, forwards), or what permission/authorization is required.
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 only four words, which is terse but not meaningfully concise—it is under-specification. Nothing is front-loaded because there is no information to front-load; the sentence says nothing beyond what the tool name already communicates.
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?
The tool has high complexity: a free-form nested params object, no output schema, no annotations, and a large sibling family of mail_* tools. The description contributes essentially nothing an agent needs—valid updatable fields, replacement vs merge semantics, return value, or prerequisites—so an agent cannot safely invoke it correctly.
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 the baseline is 3. The description adds no parameter-level meaning, and the schema's own descriptions are thin ("Client ID", "Fields to update"), but per the rubric the schema is doing the heavy lifting here. The free-form nature of params is left entirely unexplained.
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?
"Update a mailbox" is nearly a tautology of the tool name mail_user_update. It identifies a generic verb and resource but adds no specificity about what fields or aspects of the mailbox are affected. It also introduces terminology drift ("mailbox" vs the schema's "Mail user ID"), which is ambiguous given the sibling family uses "mail_user" naming.
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 given on when to use this tool versus mail_user_add, mail_user_delete, or mail_user_get. No prerequisites are stated (e.g., whether the user or mail domain must already exist), and no conditions are provided for choosing an update over a create or delete.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.