assign_task
Replace a task's assignee set.
# MCP tool reference
1 callable tools.
Use tools/call at https://mcp.schedulerzero.com/mcp with the exact tool name and arguments below. The /tools/ paths in this view are documentation identifiers, not HTTP endpoints. Request execution is disabled for this reference.
Inputs are shown for personal API keys (bound) and for OAuth/delegated agents. Output schemas describe MCP structuredContent: native objects pass through; arrays, scalars and null use a data wrapper. Text content retains the native JSON result.
[Connect a client](/mcp/connect) · [Authentication and authorization](/authentication) · [Generated auth guide](/auth.md) · [Download tool catalog](/mcp-catalog.json) · [Agent documentation](/llms.txt)
## assign_task
Replace a task's assignee set.
Use to route work to current workspace members.
A pending human request can never be left without a possible responder; the call fails instead.
Scopes: task:update
Risk: write; confirmation: none; idempotency: supported.
### Input schema (personal API key)
```json
{
"type": "object",
"properties": {
"workspaceId": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"taskId": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"userIds": {
"type": "array",
"items": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"maxItems": 20
}
},
"required": [
"workspaceId",
"taskId",
"userIds"
],
"patternProperties": {
"^(?!(?:workspaceId|taskId|userIds)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"workspaceId",
"taskId",
"userIds"
]
}
}
```
### Input schema (OAuth / delegated agent)
```json
{
"type": "object",
"properties": {
"workspaceId": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"taskId": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"userIds": {
"type": "array",
"items": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"maxItems": 20
}
},
"required": [
"workspaceId",
"taskId",
"userIds"
],
"patternProperties": {
"^(?!(?:workspaceId|taskId|userIds)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"workspaceId",
"taskId",
"userIds"
]
}
}
```
### Output schema (structuredContent)
```json
{
"type": "object",
"properties": {
"id": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"workspaceId": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"title": {
"type": "string",
"minLength": 1,
"maxLength": 2000
},
"description": {
"anyOf": [
{
"type": "string",
"maxLength": 10000
},
{
"type": "null"
}
]
},
"dueDate": {
"anyOf": [
{
"$ref": "#/$defs/UtcDateTimeEncoded"
},
{
"type": "null"
}
]
},
"completedAt": {
"anyOf": [
{
"$ref": "#/$defs/UtcDateTimeEncoded"
},
{
"type": "null"
}
]
},
"completedBy": {
"anyOf": [
{
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
{
"type": "null"
}
]
},
"outcome": {
"anyOf": [
{
"type": "string",
"enum": [
"no_luck",
"responded",
"bad_info"
]
},
{
"type": "null"
}
]
},
"leadId": {
"anyOf": [
{
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
{
"type": "null"
}
]
},
"campaignContactId": {
"anyOf": [
{
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
{
"type": "null"
}
]
},
"campaignStepId": {
"anyOf": [
{
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
{
"type": "null"
}
]
},
"workflowRunId": {
"anyOf": [
{
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
{
"type": "null"
}
]
},
"workflow": {
"anyOf": [
{
"type": "object",
"properties": {
"id": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"name": {
"$ref": "#/$defs/ShortText"
}
},
"required": [
"id",
"name"
],
"patternProperties": {
"^(?!(?:id|name)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"id",
"name"
]
}
},
{
"type": "null"
}
]
},
"humanRequest": {
"anyOf": [
{
"anyOf": [
{
"type": "object",
"properties": {
"type": {
"type": "string",
"enum": [
"approval",
"text"
]
},
"question": {
"$ref": "#/$defs/Description"
}
},
"required": [
"type",
"question"
],
"patternProperties": {
"^(?!(?:type|question)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"type",
"question"
]
}
},
{
"type": "object",
"properties": {
"type": {
"anyOf": [
{
"type": "string",
"enum": [
"choice"
]
}
]
},
"question": {
"$ref": "#/$defs/Description"
},
"options": {
"type": "array",
"items": {
"$ref": "#/$defs/NonEmptyString"
},
"maxItems": 20
}
},
"required": [
"type",
"question",
"options"
],
"patternProperties": {
"^(?!(?:type|question|options)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"type",
"question",
"options"
]
}
}
]
},
{
"type": "null"
}
]
},
"humanResponse": {
"anyOf": [
{
"anyOf": [
{
"type": "object",
"properties": {
"type": {
"anyOf": [
{
"type": "string",
"enum": [
"approval"
]
}
]
},
"approved": {
"type": "boolean"
},
"comment": {
"$ref": "#/$defs/ShortText"
}
},
"required": [
"type",
"approved"
],
"patternProperties": {
"^(?!(?:type|approved|comment)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"type",
"approved",
"comment"
]
}
},
{
"type": "object",
"properties": {
"type": {
"anyOf": [
{
"type": "string",
"enum": [
"text"
]
}
]
},
"text": {
"$ref": "#/$defs/Description"
}
},
"required": [
"type",
"text"
],
"patternProperties": {
"^(?!(?:type|text)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"type",
"text"
]
}
},
{
"type": "object",
"properties": {
"type": {
"anyOf": [
{
"type": "string",
"enum": [
"choice"
]
}
]
},
"choice": {
"$ref": "#/$defs/NonEmptyString"
}
},
"required": [
"type",
"choice"
],
"patternProperties": {
"^(?!(?:type|choice)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"type",
"choice"
]
}
}
]
},
{
"type": "null"
}
]
},
"requestState": {
"anyOf": [
{
"type": "string",
"enum": [
"pending",
"answered",
"expired",
"cancelled"
]
},
{
"type": "null"
}
]
},
"responseExpiresAt": {
"anyOf": [
{
"$ref": "#/$defs/UtcDateTimeEncoded"
},
{
"type": "null"
}
]
},
"requestedByAgentRegistrationId": {
"anyOf": [
{
"$ref": "#/$defs/OpaqueId"
},
{
"type": "null"
}
]
},
"operationId": {
"anyOf": [
{
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
{
"type": "null"
}
]
},
"assignees": {
"type": "array",
"items": {
"type": "object",
"properties": {
"userId": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"name": {
"$ref": "#/$defs/ShortText"
},
"email": {
"$ref": "#/$defs/EmailAddress"
},
"image": {
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
]
},
"inOrg": {
"type": "boolean"
}
},
"required": [
"userId",
"name",
"email",
"image",
"inOrg"
],
"patternProperties": {
"^(?!(?:userId|name|email|image|inOrg)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"userId",
"name",
"email",
"image",
"inOrg"
]
}
}
},
"createdBy": {
"anyOf": [
{
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
{
"type": "null"
}
]
},
"createdByUser": {
"anyOf": [
{
"type": "object",
"properties": {
"userId": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"name": {
"$ref": "#/$defs/ShortText"
},
"email": {
"$ref": "#/$defs/EmailAddress"
},
"image": {
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
]
},
"inOrg": {
"type": "boolean"
}
},
"required": [
"userId",
"name",
"email",
"image",
"inOrg"
],
"patternProperties": {
"^(?!(?:userId|name|email|image|inOrg)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"userId",
"name",
"email",
"image",
"inOrg"
]
}
},
{
"type": "null"
}
]
},
"completedByUser": {
"anyOf": [
{
"type": "object",
"properties": {
"userId": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"name": {
"$ref": "#/$defs/ShortText"
},
"email": {
"$ref": "#/$defs/EmailAddress"
},
"image": {
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
]
},
"inOrg": {
"type": "boolean"
}
},
"required": [
"userId",
"name",
"email",
"image",
"inOrg"
],
"patternProperties": {
"^(?!(?:userId|name|email|image|inOrg)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"userId",
"name",
"email",
"image",
"inOrg"
]
}
},
{
"type": "null"
}
]
},
"lead": {
"anyOf": [
{
"type": "object",
"properties": {
"id": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"firstName": {
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
]
},
"lastName": {
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
]
},
"companyName": {
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
]
},
"emailAddress": {
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
]
},
"phoneNumber": {
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
]
}
},
"required": [
"id",
"firstName",
"lastName",
"companyName",
"emailAddress",
"phoneNumber"
],
"patternProperties": {
"^(?!(?:id|firstName|lastName|companyName|emailAddress|phoneNumber)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"id",
"firstName",
"lastName",
"companyName",
"emailAddress",
"phoneNumber"
]
}
},
{
"type": "null"
}
]
},
"outcomeDetail": {
"anyOf": [
{
"type": "object",
"properties": {
"phoneOutcomes": {
"type": "array",
"items": {
"type": "object",
"properties": {
"leadPhoneId": {
"type": "string",
"pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
"format": "uuid"
},
"outcome": {
"type": "string",
"enum": [
"no_luck",
"responded",
"bad_info"
]
}
},
"required": [
"leadPhoneId",
"outcome"
],
"patternProperties": {
"^(?!(?:leadPhoneId|outcome)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"leadPhoneId",
"outcome"
]
}
},
"maxItems": 50
}
},
"required": [
"phoneOutcomes"
],
"patternProperties": {
"^(?!(?:phoneOutcomes)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"anyOf": [
{
"type": "string",
"enum": [
"phoneOutcomes"
]
}
]
}
},
{
"type": "null"
}
]
},
"createdAt": {
"$ref": "#/$defs/UtcDateTimeEncoded"
},
"updatedAt": {
"$ref": "#/$defs/UtcDateTimeEncoded"
}
},
"required": [
"id",
"workspaceId",
"title",
"description",
"dueDate",
"completedAt",
"completedBy",
"outcome",
"leadId",
"campaignContactId",
"campaignStepId",
"workflowRunId",
"workflow",
"humanRequest",
"humanResponse",
"requestState",
"responseExpiresAt",
"requestedByAgentRegistrationId",
"operationId",
"assignees",
"createdBy",
"createdAt",
"updatedAt"
],
"patternProperties": {
"^(?!(?:id|workspaceId|title|description|dueDate|completedAt|completedBy|outcome|leadId|campaignContactId|campaignStepId|workflowRunId|workflow|humanRequest|humanResponse|requestState|responseExpiresAt|requestedByAgentRegistrationId|operationId|assignees|createdBy|createdByUser|completedByUser|lead|outcomeDetail|createdAt|updatedAt)$)[\\s\\S]*$": false
},
"additionalProperties": true,
"propertyNames": {
"type": "string",
"enum": [
"id",
"workspaceId",
"title",
"description",
"dueDate",
"completedAt",
"completedBy",
"outcome",
"leadId",
"campaignContactId",
"campaignStepId",
"workflowRunId",
"workflow",
"humanRequest",
"humanResponse",
"requestState",
"responseExpiresAt",
"requestedByAgentRegistrationId",
"operationId",
"assignees",
"createdBy",
"createdByUser",
"completedByUser",
"lead",
"outcomeDetail",
"createdAt",
"updatedAt"
]
},
"$defs": {
"UtcDateTimeEncoded": {
"type": "string",
"pattern": "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}\\.\\d{3}Z$"
},
"ShortText": {
"type": "string",
"minLength": 1,
"maxLength": 256
},
"Description": {
"type": "string",
"minLength": 1,
"maxLength": 4096
},
"NonEmptyString": {
"type": "string",
"minLength": 1,
"maxLength": 4096
},
"OpaqueId": {
"type": "string",
"minLength": 1,
"maxLength": 512
},
"EmailAddress": {
"type": "string",
"minLength": 3,
"maxLength": 320,
"pattern": "^[^\\s@]+@[^\\s@]+\\.[^\\s@]+$"
}
}
}
```
### Underlying API operations
- `tasks.setAssignees`: `POST /v1/workspaces/:workspaceId/tasks/:taskId/assignees`
Scheduler Zero