Mailrith Email Marketing

Update a sequence

sequences_update

DestructiveIdempotent

Updates an existing paused Sequence. Before changing a running Sequence, read it by ID, retain its status in the current task only, pause it, apply the update, and use bounded direct item reads until is_updating is false. Run preflight, return it to running only if it was running before and preflight passes, and verify the final status. If the update fails before changing the Sequence, restore its prior running status when preflight passes. If readiness or the prior status cannot be restored, leave it paused and immediately report the failure; never activate a Sequence that was not already running. Effect: workspace-change. Retry after reading the current resource state. Permission: sequences:write. API reference: https://mailrith.com/developers/api-reference.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "sequence_id": "<sequence_id>",
      "body": "<body>"
    },
    "name": "sequences_update"
  }
}

Input Schema

Name	Required	Description	Default
`body`	Yes	The exact JSON request body defined by the Mailrith public API contract.
`sequence_id`	Yes	The sequence identifier.

Output Schema

Name	Required	Description
`error`	No
`response`	No
`request_id`	Yes	The stable correlation ID for this MCP tool invocation.
`operation_id`	Yes	The stable Mailrith public API operation ID.

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedNov 2, 2026

changedInput schema / $defs / SequenceUpdateRequest / properties / reply_to_email / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "description": "Empty or null uses the sender's current Reply-To. With a Mailrith sending domain, a value must be the workspace owner's verified account email or an address on that sender's domain, or the request fails with invalid_reply_to_email.",
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

changedOutput schema / $defs / Sequence / properties / reply_to_email / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "description": "An override for this email's Reply-To. Null uses the sender's current Reply-To when the email is sent.",
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

Changed10 schema fields changedSep 3, 2026

changedInput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedInput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello from Mailrith.",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedInput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello from Mailrith.",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

addedInput schema / $defs / SequenceEmail / properties / subject / description

Added value: +"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedOutput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedOutput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello from Mailrith.",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedOutput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello from Mailrith.",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

addedOutput schema / $defs / BroadcastSendProgress / properties / sent
```
Added value: +{
+  "type": "integer"
+}
```

changedOutput schema / $defs / BroadcastSendProgress / required

Previous value: -[
-  "run_id",
-  "phase",
-  "selected",
-  "materialized",
-  "accepted",
-  "skipped",
-  "retrying",
-  "permanent_failed",
-  "unknown",
-  "canceled",
-  "percent_complete",
-  "effective_rate",
-  "provider_limited_rate",
-  "provider",
-  "estimated_completion",
-  "estimated_completion_basis",
-  "last_progress_at",
-  "pause_reason",
-  "next_retry_at",
-  "next_retry_action",
-  "pause_message",
-  "terminal"
-]New value: +[
+  "run_id",
+  "phase",
+  "selected",
+  "materialized",
+  "sent",
+  "accepted",
+  "skipped",
+  "retrying",
+  "permanent_failed",
+  "unknown",
+  "canceled",
+  "percent_complete",
+  "effective_rate",
+  "provider_limited_rate",
+  "provider",
+  "estimated_completion",
+  "estimated_completion_basis",
+  "last_progress_at",
+  "pause_reason",
+  "next_retry_at",
+  "next_retry_action",
+  "pause_message",
+  "terminal"
+]

addedOutput schema / $defs / SequenceEmail / properties / subject / description

Added value: +"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

Changed10 schema fields changedSep 3, 2026

changedInput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes."

changedInput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello from Mailrith.",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedInput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello from Mailrith.",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

removedInput schema / $defs / SequenceEmail / properties / subject / description

Removed value: -"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedOutput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes."

changedOutput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello from Mailrith.",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedOutput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello from Mailrith.",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

removedOutput schema / $defs / BroadcastSendProgress / properties / sent
```
Removed value: -{
-  "type": "integer"
-}
```

changedOutput schema / $defs / BroadcastSendProgress / required

Previous value: -[
-  "run_id",
-  "phase",
-  "selected",
-  "materialized",
-  "sent",
-  "accepted",
-  "skipped",
-  "retrying",
-  "permanent_failed",
-  "unknown",
-  "canceled",
-  "percent_complete",
-  "effective_rate",
-  "provider_limited_rate",
-  "provider",
-  "estimated_completion",
-  "estimated_completion_basis",
-  "last_progress_at",
-  "pause_reason",
-  "next_retry_at",
-  "next_retry_action",
-  "pause_message",
-  "terminal"
-]New value: +[
+  "run_id",
+  "phase",
+  "selected",
+  "materialized",
+  "accepted",
+  "skipped",
+  "retrying",
+  "permanent_failed",
+  "unknown",
+  "canceled",
+  "percent_complete",
+  "effective_rate",
+  "provider_limited_rate",
+  "provider",
+  "estimated_completion",
+  "estimated_completion_basis",
+  "last_progress_at",
+  "pause_reason",
+  "next_retry_at",
+  "next_retry_action",
+  "pause_message",
+  "terminal"
+]

removedOutput schema / $defs / SequenceEmail / properties / subject / description

Removed value: -"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

Changed8 schema fields changedAug 17, 2026

changedInput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedInput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello from Mailrith.",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedInput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello from Mailrith.",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

addedInput schema / $defs / SequenceEmail / properties / subject / description

Added value: +"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedOutput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedOutput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello from Mailrith.",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedOutput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello from Mailrith.",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

addedOutput schema / $defs / SequenceEmail / properties / subject / description

Added value: +"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

Changed2 schema fields changedAug 7, 2026

addedOutput schema / $defs / BroadcastSendProgress / properties / sent
```
Added value: +{
+  "type": "integer"
+}
```

changedOutput schema / $defs / BroadcastSendProgress / required

Previous value: -[
-  "run_id",
-  "phase",
-  "selected",
-  "materialized",
-  "accepted",
-  "skipped",
-  "retrying",
-  "permanent_failed",
-  "unknown",
-  "canceled",
-  "percent_complete",
-  "effective_rate",
-  "provider_limited_rate",
-  "provider",
-  "estimated_completion",
-  "estimated_completion_basis",
-  "last_progress_at",
-  "pause_reason",
-  "next_retry_at",
-  "next_retry_action",
-  "pause_message",
-  "terminal"
-]New value: +[
+  "run_id",
+  "phase",
+  "selected",
+  "materialized",
+  "sent",
+  "accepted",
+  "skipped",
+  "retrying",
+  "permanent_failed",
+  "unknown",
+  "canceled",
+  "percent_complete",
+  "effective_rate",
+  "provider_limited_rate",
+  "provider",
+  "estimated_completion",
+  "estimated_completion_basis",
+  "last_progress_at",
+  "pause_reason",
+  "next_retry_at",
+  "next_retry_action",
+  "pause_message",
+  "terminal"
+]

First observedJul 30, 2026

TDQS

A4.1/5.0

Behavior5/5

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

Adds substantial context beyond the annotations: the declared 'Effect: workspace-change', the required permission (sequences:write), the retry-after-read semantics, the failure/rollback contract (restore prior running status only if preflight passes), and the explicit prohibition on activating non-running sequences. This complements destructiveHint=true and idempotentHint=true rather than repeating them.

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

Conciseness4/5

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

Purpose and the key constraint are front-loaded, and there is no filler — every clause covers a real safety rule. The middle is a dense imperative runbook that takes effort to parse, which slightly hurts readability but not economy.

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 destructive mutation with an output schema and rich nested input schema, the description covers preconditions, sequencing, failure handling, permissions, and retry policy. An agent has everything needed to call it safely without consulting external docs.

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 coverage is 100% and the nested body schema is richly documented (including reply_to_email constraints and personalization-token rules), so the schema does the heavy lifting. The description adds nothing about what fields of the update body are meaningful or how partial updates behave, leaving it at baseline.

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

Purpose4/5

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

Opens with a specific verb+resource and a scoping constraint: 'Updates an existing paused Sequence.' That scope implicitly separates it from sequences_update_status (status transitions) and sequences_preflight, though no sibling is named explicitly, so an agent must infer the routing rather than read it.

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?

Gives concrete when/when-not conditions: only update paused sequences directly; for running ones, read → pause → update → restore. It also names the preflight step and forbids activating a sequence that was not already running. It stops short of explicitly pointing to the sibling tools by name (e.g., sequences_update_status for pure status changes).

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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Update a sequence

Tool call template

Input Schema

Output Schema

Schema Changelog

TDQS

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