email_usersDrafts an email to the app's users (all or one plan). Returns approve_url: nothing is sent until the Site Owner approves.
| Name | Required | Description | Default |
|---|---|---|---|
| body | Yes | Plain text | |
| plan | No | Plan id; default all | |
| site | Yes | ||
| subject | Yes | ||
| confirm_token | No |
| Name | Required | Description | Default |
|---|---|---|---|
| days | No | ||
| recipients | No | ||
| approve_url | No | ||
| agent_message | No | ||
| confirm_token | No |
Changes observed during successful MCP inspections.
Output schema / properties / agent_messageAdded value: +{
+ "type": "string"
+}Output schema / properties / approve_urlAdded value: +{
+ "type": "string"
+}Output schema / properties / daysAdded value: +{
+ "type": "number"
+}Output schema / properties / recipientsAdded value: +{
+ "type": "number"
+}Output schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "confirm_token": {
+ "type": "string"
+ }
+ },
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds important behavior beyond the annotations: it returns approve_url and nothing is sent until the Site Owner approves. This approval workflow is valuable context. The only gap is that it does not reconcile the draft-only behavior with the destructiveHint annotation or explain permissions beyond Site Owner approval.
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 sentences, front-loaded, with no wasted text. The scope and approval constraint are stated 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?
The presence of an output schema means return values need not be fully explained, and the annotations cover the safety profile. Still, for a 5-parameter mutation-style tool with low schema coverage, the description should explain the confirm_token and site parameters more fully to be 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 only 40%, so the description should compensate. It clarifies that plan can mean all users or one plan, but it leaves site, subject, and especially confirm_token unexplained, even though confirm_token is likely central to the approval flow.
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 specific verb and resource: drafts an email to the app's users, with scope limited to all users or one plan. This is clear and specific enough for an agent to distinguish it from unrelated sibling tools such as invite_users or remove_user.
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?
It indicates that the tool creates a draft and that sending requires Site Owner approval, which is useful usage context. However, it does not explain when to choose this over alternatives, nor does it mention prerequisites or when not to use it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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