add-tag-to-contactsAssign a tag to one or more contacts to group them and start any active automations that may send messages.
Add a tag to contacts. This can start the organization's active automations, which may send messages.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | The tag id. | |
| contact_ids | Yes | Contact ids, from list-contacts. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=false, so the mutation/non-idempotent profile is covered. The description adds genuinely useful context beyond that: tagging can trigger active automations that send messages, a side effect not derivable from the structured fields.
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?
Two tight sentences, zero waste. The core action is front-loaded first, and the side-effect warning follows immediately.
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 two-parameter mutation with full schema coverage and no output schema, the description supplies the key missing piece: the automation/message-sending side effect. It could say more about failure modes (e.g., invalid tag id), but it is largely complete.
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%, with both 'id' and 'contact_ids' documented, including a helpful pointer that contact ids come from list-contacts. The description adds nothing beyond the schema, so the baseline of 3 applies.
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 gives a specific verb+resource ('Add a tag to contacts'), so an agent immediately knows the operation. It does not explicitly name its sibling remove-tag-from-contacts, but the direction of the operation is unambiguous.
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?
There is no guidance on when to use this tool versus alternatives such as add-contacts-to-list or remove-tag-from-contacts, and no preconditions are stated. Usage must be inferred entirely from the name.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.