Modify a contact list's name, description, and double opt-in setting by ID to keep subscriber preferences and list details current.
Replace a contact list's name, description and double opt-in setting.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Contact list UUID | |
| name | Yes | List name | |
| description | No | List description | |
| double_opt_in | No | Require double opt-in |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. 'Replace' is the single useful behavioral signal, but the description never says what happens to omitted fields (are description/double_opt_in cleared or preserved?), whether the change is reversible, or what permissions are needed — critical for a mutation tool.
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?
One sentence, front-loaded with the verb and resource, zero filler. It is arguably too terse rather than too long, but nothing is redundant.
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 mutation tool with no annotations and no output schema, the description should clarify partial-vs-full update semantics and side effects. The word 'Replace' gestures at this but does not resolve it, leaving an agent unable to predict the result of omitting optional fields.
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 each of the four parameters is already documented. The description enumerates the three mutable fields, which confirms which parameters this tool writes, but adds no format, constraint, or default information beyond the schema.
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?
Specific verb ('Replace') plus resource ('a contact list') plus the exact fields affected, which distinguishes it from create/get/delete_contact_list siblings. The only wrinkle is that 'Replace' implies full PUT semantics while the required-only 'name' schema hints at partial update, leaving a small ambiguity about scope.
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 statement of when to use this versus create_contact_list or get_contact_list, and no prerequisites (e.g., list must exist, must not be in use). Usage is only implied by the verb.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.