> ## Documentation Index
> Fetch the complete documentation index at: https://help.withallo.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Add tags

> Add one or more tags to a conversation item.

<Note>
  **Required scope:** `TAGS_WRITE`
</Note>

## Behavior

Pass tag **keys** (lowercase, slugified identifiers) — not display names. List available tags with `GET /v2/api/tags` to get the keys.

Adding a tag that already exists on the item returns a `409` error with code `TAG_ALREADY_EXISTS`. No action is taken — the tag remains applied.

## Idempotency

This endpoint supports the `Idempotency-Key` header. If a request succeeds and you retry with the same key, the stored response is returned without re-executing the operation. See [Idempotency](/en/v2/api-reference/guides/error-handling#idempotency).


## OpenAPI

````yaml POST /v2/api/conversations/items/{id}/tags
openapi: 3.0.3
info:
  title: Allo API
  description: >-
    Allo API provides programmatic access to your Allo account, allowing you to
    manage webhooks, retrieve calls and contacts, and send SMS messages.


    All requests to `/v1/api/**` endpoints automatically go through quota
    checking and scope validation.
  version: 1.0.0
  contact:
    name: Allo Support
servers:
  - url: https://api.withallo.com
    description: Production server
security: []
tags:
  - name: Summary Templates
    description: >-
      Manage call summary templates that control how AI-generated call summaries
      are structured for your team.
  - name: Webhooks
    description: >-
      Manage webhook endpoints to receive real-time notifications about events
      in your Allo account. Each endpoint subscribes to one or more event topics
      and is verified with a signing secret.
  - name: Calls
    description: >-
      Retrieve and search call records with filtering and pagination. Filter
      calls by your Allo phone number.
  - name: Contacts
    description: >-
      Search and retrieve contact information with sorting and pagination.
      Includes engagement level tracking.
  - name: SMS
    description: Send SMS messages to phone numbers using your Allo numbers.
  - name: Phone Numbers
    description: Retrieve information about your Allo phone numbers.
  - name: Analytics
    description: Pre-computed call metrics, team performance, and outbound dial funnel
  - name: CRM
    description: Manage people, companies, and deals in your CRM.
paths:
  /v2/api/conversations/items/{id}/tags:
    post:
      tags:
        - Tags
      summary: Add tags
      description: Add one or more tags to a conversation item.
      operationId: addTags
      parameters:
        - name: id
          in: path
          required: true
          description: Call ID (`cll-*`)
          schema:
            type: string
            example: cll-abc123
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                tags:
                  type: array
                  items:
                    type: string
                  description: Tag keys to add
              required:
                - tags
            example:
              tags:
                - qualified
                - follow_up
      responses:
        '200':
          description: Tags added successfully
        '401':
          $ref: '#/components/responses/ApiUnauthorized'
        '404':
          $ref: '#/components/responses/ApiNotFound'
        '429':
          $ref: '#/components/responses/ApiRateLimited'
      security:
        - ApiKeyAuth: []
components:
  responses:
    ApiUnauthorized:
      description: Invalid or missing API key
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ApiError'
    ApiNotFound:
      description: Resource not found
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ApiError'
    ApiRateLimited:
      description: Rate limit exceeded
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ApiError'
  schemas:
    ApiError:
      type: object
      properties:
        error:
          type: object
          properties:
            type:
              type: string
            code:
              type: string
            message:
              type: string
            retryable:
              type: boolean
            request_id:
              type: string
            retry_after_seconds:
              type: integer
              nullable: true
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: Authorization

````