MCP Emails

Schedule a pending send

approval_schedule

Idempotent

Set the future delivery time for an email awaiting approval. This action schedules when the approved message will be sent, without queuing it before approval.

Instructions

Set the delivery time of a send that is waiting for human approval. Nothing is queued until it is approved; this only decides when an approved message goes out. send_at must be in the future.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`send_at`	Yes	ISO 8601 timestamp with timezone, in the future.
`approval_id`	Yes	The approval_id returned by a gated send (status: "pending_approval").

Output Schema

TableJSON Schema

Name	Required	Description
`card`	No	Which card this envelope renders: 'outbound_review' or 'receipt'.
`state`	No	Where the request stands: pending, approved, rejected, expired or sent.
`dashboard_url`	No	Absolute link to the signed-in approvals page. Always present, and the one link that still works when the rest of the envelope cannot be parsed.
`schema_version`	No	Card envelope version. A client that does not know this version should fall back to dashboard_url.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedSep 10, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "additionalProperties": true,
+  "properties": {
+    "card": {
+      "description": "Which card this envelope renders: 'outbound_review' or 'receipt'.",
+      "type": "string"
+    },
+    "dashboard_url": {
+      "description": "Absolute link to the signed-in approvals page. Always present, and the one link that still works when the rest of the envelope cannot be parsed.",
+      "type": "string"
+    },
+    "schema_version": {
+      "description": "Card envelope version. A client that does not know this version should fall back to dashboard_url.",
+      "type": "integer"
+    },
+    "state": {
+      "description": "Where the request stands: pending, approved, rejected, expired or sent.",
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

First observedv1.0.4Aug 30, 2026

TDQS

A4.3/5.0

Behavior4/5

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

The description usefully explains that this sets a delivery time without queuing anything, and only applies to an approved message going out. Annotations already signal idempotent/non-destructive; the description adds the sequencing behavior and the precondition that approval must happen first.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded verb and resource, no filler. It states what it does, the key constraint, and a clarifying behavior all in compact form.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a two-parameter tool with full schema coverageavorite and an output schema, the description fully covers when to use it and what it does not do. Nothing essential is missing for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% for both parametersais4, and the description mainly restates the schema's future-time constraint for send_ataiman. It doesn't add meaning beyond what the schema already provides, so baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb plus resource: 'Set the delivery time of a send that is waiting for human approval.' It clearly separates this tool from general scheduling by emphasizing it applies only to sends in the pending-approval state. This distinguishes it from siblings like schedule.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description states exactly when the tool applies: to a send waiting for human approval qui n'est pas encore programmé, and it clarifies that nothing is queued until approved. It lacks an explicit 'use X instead' exclusion, but the context is clear enough that an agent can identify this as the approval-specific scheduling path.

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