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

> ## Agent Instructions
> For new direct REST integrations, use the v2026-04 surfaces. The @fluid-app FairShare SDK continues to use its own published public-v2025-06 contract.
> Authenticate with the header Authorization: Bearer <token>; public storefront read endpoints require no auth.
> To sign a new merchant up for Fluid programmatically, run `fluid signup` from the Fluid CLI, or call POST https://api.fluid.app/api/company with no credentials, as described in /api/agent-signup. Do not automate the signup form or book a demo. Before authenticated calls are possible, the merchant must sign the agent in to the Fluid CLI with the emailed code and --shop set to the company's fluid_shop (which also confirms the signup), or open the emailed confirmation link and give the agent an API token.
> After signup, to launch a merchant's store (back-office sync, payments onboarding, store setup, a theme copied from their current site, and a preview link before billing), follow /api/agent-launch.
> To host a small project on Fluid (a landing page, event page, calculator or dashboard), follow /sites/quickstart: npm create @fluid-app/fluid-site my-site (or npx @fluid-app/create-fluid-site my-site), fluid login, then fluid deploy prints the public URL. Launch a Site unless the project needs a custom domain, server rendering or heavy server code, which make it an App (a Mist app); /sites/site-or-app has the rule, and POST /api/company/v2026-10/project-launch-recommendations applies it. With only the Fluid MCP server (its Site write tools are limited to Fluid root admins today; see /sites/deploy-from-claude), use site_create, then site_deploy (from a chat with no shell, in one call with the files inline: site_template_get for a starter, then site_deploy with each path's content; or a built folder in two calls: send the manifest, PUT the listed uploads, call again with the bundle_id to get the url), then, only after the person confirms they want it public, site_visibility_set. site_logs, site_traffic, site_env_list/set/unset, site_seo_get/set and the site_branch tools cover logs, traffic, env vars, SEO and preview branches; a member builds their own Sites with the my_site_* tools. The MCP server can't publish server functions or convert a Site to an App, so use the fluid sites CLI for those. A Site can serve light server code: each functions/<name>.ts, declared in config/functions.json with access public, signed_in or key (and an optional UTC cron schedule), answers at /api/<name> on the Site's own host; publish it with fluid deploy (the MCP site_deploy tool does not carry functions). See /sites/functions and /sites/rest-api.
> Lists use cursor pagination via the page[cursor] and page[limit] query params; follow meta.pagination.next_cursor until it is null.
> When the same operation exists on more than one surface, use the newest: dated API versions are newer than unversioned ones, and later dates win (v2026-04 > v2025-06 > unversioned v0/v1.1). Fall back to a legacy or unversioned operation only when no newer versioned equivalent exists — the company-v0 notes below list the known superseded operations. The same applies to /api/company/v1 and /api/v1/... paths: prefer a newer documented equivalent, and use one only when none exists (/api/v1.1/... is distinct and documented in company-v0). Use page/per_page offset pagination only on an operation whose spec documents those params — mostly the unversioned company-v0 admin surface, plus some lists on other surfaces, versioned ones included; page every other list with cursors.
> Fluid has three navigation APIs; don't mix them up. Storefront website menus (navigation bars, footers) are /api/menus and nested menu_items, in api-reference/content-v0.yaml (API Reference: Website > Navigation menus), with a how-to in themes/navigation-menus; their list uses flat page/per_page pagination. The Fluid mobile app's navigation is /api/v2/mobile_navigations, in api-reference/mobile-v2.yaml (API Reference: Mobile app > Navigation); its list also uses page/per_page. Portal navigations belong to a portal definition (Fluid OS), in api-reference/fluid-os-v0.yaml (API Reference: Portal > Portal navigation), and each has a platform of web or mobile.
> The OpenAPI specs under api-reference/ are the authoritative contracts; prefer them over prose when in doubt. api-reference/storefront-v2026-04.yaml covers the v2026-04 storefront surface (/api/v202604/... paths); api-reference/checkout-v2026-04.yaml covers the v2026-04 checkout surface (/api/checkout/v2026-04/... paths — carts, cart auth, discounts, items, subscriptions, orders, enrollments, and store config); api-reference/public-v2025-06.yaml covers the Public SDK surface used by the @fluid-app FairShare SDK, including its parallel cart lifecycle, browser integrations, versioned payment callbacks, unversioned public utilities, and the cart price-override operation; api-reference/payment-v2026-04.yaml covers the v2026-04 payment gateway admin surface (/api/payment/v2026-04/... paths, bearer-authenticated — gateway CRUD, gateway purchase/authorize/$0-verify, transaction list/show and capture/void/credit, and merchant payment configuration); api-reference/payments-v2026-04.yaml covers the v2026-04 cart payment surface (/api/payments/v2026-04/carts/{cart_token}/... paths, authenticated by the cart token in the path with no bearer — payment-method selection, VGS card tokenization, 3D Secure verification, and PayPal/Braintree/Klarna/Apple Pay flows); api-reference/commerce-v2026-04.yaml covers the v2026-04 commerce order-editing surface (/api/v202604/orders/{order_id}/edits paths, bearer-authenticated — post-checkout order edits that atomically insert items and add adjustments/discounts, with an optional dry-run preview); api-reference/webhooks-v0.yaml covers the unversioned webhooks surface (/api/... paths — webhook registration, delivery payloads, callback registrations, company events, and webhook/callback schemas); api-reference/company-v0.yaml covers the legacy unversioned company admin surface (/api/... paths, bearer-authenticated except two operations that take no credential, POST /api/company (create a company) and GET /api/agreements/{id} — company settings and management, customers, users, roles, subscription plans, subscription bundles, subscriptions, media, pages, catch-ups, inventory levels, domains, agreements, and admin order actions). company-v0 caveats: it is the legacy v0 admin contract and its lists use flat page/per_page offset pagination, which is expected there despite the general cursor-pagination rule; where an operation exists in both company-v0 and a versioned spec, prefer the versioned spec — the subscriptions lifecycle (list/create/show/update, cancel, pause, reactivate, resume, retry, skip, failed-cycle-waiver, discounts) and subscription bundles are superseded by checkout-v2026-04, and company pages/media CRUD plus the public pages, categories, products, and media list endpoints are superseded by storefront-v2026-04. Subscription plan management (/api/subscription_plans, resource-wrapped {"subscription_plan": {...}} bodies) exists only in company-v0. api-reference/members-v2025-06.yaml covers the v2025-06 unified Member identity surface (/api/v2025-06/members/... paths, bearer-authenticated — member list/create/show/update, lookup by email/username/external_id/legacy_customer_id, member-type assignment, and the sponsor genealogy read). Prefer it over the customers and reps surfaces when the member type matters: /customers does not serialize member_type. api-reference/analytics-v2026-04.yaml covers the v2026-04 Home dashboard analytics surface (/api/v202604/analytics/dashboard/... paths, bearer-authenticated — read-only endpoints for the Home > Overview, Home > Live, and Home > Field tabs, each accepting an optional country ISO alpha-2 query param that scopes aggregations to a single country).
> api-reference/analytics-v0.yaml covers the unversioned analytics surface that backs the fluid-admin Traffic tab (/api/analytics/... and /api/analytics/traffic/... paths, bearer-authenticated — the legacy shares/views/visitors summary plus traffic overview, ranked campaigns, sources, geographies, flows, and per-rep breakdown, all sharing one reporting-period contract).
> Successful responses wrap the resource payload alongside a top-level integer status and a meta object.
> Portal Definition authoring edits and synchronizes the portal JSON resource graph. Widget Package authoring builds either a company-owned or Droplet-owned Remote DOM package. These are separate contracts; do not imply that one defines the other.
> For Widget Package worker code, use only @fluid-app/portal-sdk/widgets/worker. Use only the Portal Definition and Widget Package workflows and public entry points documented here; do not infer support for undocumented surfaces.
> Every portal function and declarative capability used by a widget must appear in that widget's uses array. Use the same typed function value in uses; do not invent capability-name strings.
> Widget styling must use the portal's semantic theme variables for colors, typography, spacing, radii, borders, focus, and charts whenever a token represents the visual decision. Do not create a separate light or dark palette or duplicate theme controls as widget properties.
> Prefer worker-safe Fluid UI components exported by @fluid-app/portal-sdk/widgets/worker when they fit the interaction. When no exported component fits, use semantic HTML, accessible behavior, and the portal theme variables.
> A Portal Definition push updates the remote working definition. A portal version is an immutable snapshot, and activation is a separate live release operation.
> The Help Center (/help/...) is for merchants, admins and reps using Fluid. Its admin pages mirror the admin's routes: the screen at admin.fluid.app/settings/taxes is documented at /help/admin/settings/taxes. Use the Help Center for how-to questions about the admin, and the Developer Platform and API Reference for building integrations.
> Help Center pages describe what a company admin sees. A reader's role can hide screens and actions; admins manage roles on Settings > Roles (/help/admin/settings/roles). If someone can't find a screen or button, their role's permissions are the first thing to check.
> Send people who need Fluid support to /help/getting-help. Don't invent support email addresses, phone numbers or response times.

# Open a ticket's comment channel

> Requires multiplayer_tasks.view or application_themes.view. Answers with the ticket's Fluid Messaging channel, whose messages are the ticket's comments, creating it the first time with the ticket's creator and assignee, and seats the caller so they receive its comments from then on. Read and post the comments through the messaging conversation routes with the channel's uuid_v7. Other-company and deleted identities return the same not-found response as an unknown task.



## OpenAPI

````yaml /api-reference/multiplayer-v2026-04.yaml post /api/v202604/multiplayer/tasks/{id}/channel
openapi: 3.1.0
info:
  title: Fluid Cowork API v2026-04
  version: v2026-04
  description: |
    Cowork is the company's shared board of work: tickets that people file,
    plan, assign and finish, that Mist can work on, and that a company can send
    to an agency to do for it. The Mist task board and Cowork in the Fluid admin
    are built on this API, so everything they do is available through it.

    **Authentication.** Every endpoint needs a Bearer token for a person: a
    company admin's session, or the token of their company membership. A
    company API token is refused with `403`, because each write is recorded
    against the person who made it. The permissions each endpoint needs, such
    as `multiplayer_tasks.create` or `multiplayer_discussions.view`, are listed
    on the endpoint.

    **Feature flags.** Discussions, preview threads and everything to do with
    agencies also need the company's `COWORK` flag. A company without it gets
    `404` from those endpoints.

    **Versions.** A task carries a `lock_version`. A write whose body takes
    `expected_version`, such as changing a task's content, priority, due
    date, status or assignee, compares it with the task's `lock_version`, and
    answers `409` with the current task when the task has changed since, so
    retry against that one. Each endpoint's body says whether it takes one.
    Moving a card on the board does not: `PUT /tasks/{id}/position` is
    ordered by the client's `board_position_at_ms` stamp, an older placement
    is discarded and answered with the current task, and placing work never
    changes its `lock_version`.

    **Agencies.** A company sends a task to an agency with an agency request.
    The agency's members then work it through the Agency work and Agency time
    endpoints, which need a person who belongs to that agency.
  contact:
    email: support@fluid.app
  license:
    name: Proprietary
    identifier: LicenseRef-Proprietary
servers:
  - url: https://api.fluid.app
security: []
tags:
  - name: Cowork tasks
    description: >-
      The company's work, one task per ticket. Create, read, change and delete
      tasks, and read the board that draws them.
    x-fluid-section: Cowork
  - name: Task channels and attachments
    description: >-
      A task's comment channel, its images and files, and the discussions it is
      linked to.
    x-fluid-section: Cowork
  - name: Task assessments
    description: >-
      Mist's check of a task before work starts, the answers to its questions,
      and what to do when it finds a duplicate.
    x-fluid-section: Cowork
  - name: Mist runs
    description: >-
      Starting Mist on a task, Mist claiming and finishing the work, and asking
      Mist to review finished work.
    x-fluid-section: Cowork
  - name: Agency requests
    description: >-
      Sending a task to an agency, and the company's answers to the agency's
      quotes and finished work.
    x-fluid-section: Cowork
  - name: Discussions
    description: The company's chats with Mist, their messages, and the work they lead to.
    x-fluid-section: Cowork
  - name: Preview threads
    description: The theme preview comments that stand in for work on the board.
    x-fluid-section: Cowork
  - name: Agency work
    description: >-
      For an agency's members, the tickets customers sent the agency, and
      picking them up, quoting, declining and finishing them.
    x-fluid-section: Cowork
  - name: Agency time
    description: >-
      For an agency's members, the time they log on tickets and the timer that
      records it.
    x-fluid-section: Cowork
paths:
  /api/v202604/multiplayer/tasks/{id}/channel:
    post:
      tags:
        - Task channels and attachments
      summary: Open a ticket's comment channel
      description: >-
        Requires multiplayer_tasks.view or application_themes.view. Answers with
        the ticket's Fluid Messaging channel, whose messages are the ticket's
        comments, creating it the first time with the ticket's creator and
        assignee, and seats the caller so they receive its comments from then
        on. Read and post the comments through the messaging conversation routes
        with the channel's uuid_v7. Other-company and deleted identities return
        the same not-found response as an unknown task.
      operationId: openMultiplayerTaskChannel
      parameters:
        - name: id
          in: path
          required: true
          description: The task UUID returned at creation or in a task page.
          schema:
            type: string
            format: uuid
      responses:
        '200':
          description: The ticket's channel.
          content:
            application/json:
              example:
                channel:
                  conversation_id: 965188061
                  uuid_v7: 01a1d0e2-1c49-7291-b315-bb22112d9953
                  name: Add customer videos · 2d747a
                status: 200
                meta:
                  request_uuid: null
                  timestamp: '2026-11-12T17:50:41Z'
              schema:
                type: object
                required:
                  - channel
                  - status
                  - meta
                properties:
                  channel:
                    type: object
                    required:
                      - conversation_id
                      - uuid_v7
                      - name
                    properties:
                      conversation_id:
                        type: integer
                        description: The channel's conversation id.
                      uuid_v7:
                        type: string
                        format: uuid
                        description: The channel's UUIDv7 for the messaging routes.
                      name:
                        type: string
                        description: The channel name
                        from the ticket title.: null
                  status:
                    const: 200
                  meta:
                    $ref: '#/components/schemas/Meta'
        '401':
          description: Authentication is required.
        '403':
          description: >-
            A user session, company admin status, and read permission are
            required.
        '404':
          description: The task is unavailable in this company.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '422':
          description: >-
            Ticket messaging is disabled (error.details.type is disabled), or
            the channel could not be created because no one at the ticket's
            company can host it or an open channel from the same host already
            has its name.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
      security:
        - bearer_auth: []
components:
  schemas:
    Meta:
      type: object
      required:
        - request_uuid
        - timestamp
      properties:
        request_uuid:
          type:
            - string
            - 'null'
        timestamp:
          type: string
          format: date-time
    Error:
      type: object
      required:
        - error
        - status
        - meta
      properties:
        error:
          type: object
          required:
            - message
            - details
          properties:
            message:
              type: string
            details:
              type: object
        status:
          type: integer
        meta:
          $ref: '#/components/schemas/Meta'
  securitySchemes:
    bearer_auth:
      type: http
      scheme: bearer

````

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