> ## Documentation Index
> Fetch the complete documentation index at: https://open.manus.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# task.sendMessage
> Sends a follow-up message to a task for multi-turn conversation. Use this after [task.create](https://open.manus.ai/docs/v2/task.create) to continue talking, or to reply when `waiting_for_event_type` is `messageAskUser`. For other waiting types, use [task.confirmAction](https://open.manus.ai/docs/v2/task.confirmAction) instead.
Questions or issues? Contact us at [api-support@manus.ai](mailto:api-support@manus.ai).
**OAuth scope:** `create_task` or `manage_all_tasks` — see the [Open App](https://open.manus.ai/docs/v2/open-app) guide. With `create_task` scope, can only access tasks created by this Open App.
**Shortcut:** Use `agent-default-main_task` as `task_id` to send messages to the IM agent directly.
**Message length:** User text in `message.content` is limited to approximately **5,000 estimated tokens**. Manus uses a lightweight text estimate, so the exact character count varies by language and content. For a ContentPart array, the limit applies to the combined text of all `text` parts; file parts do not count. Input over the limit returns `InvalidArgument` (HTTP 400).
**Structured Output:** Pass `structured_output_schema` to extract a JSON result when the task next finishes. A new schema replaces the previous one. See the [Structured Output](https://open.manus.ai/docs/v2/structured-output) guide.
**Attach files:** Upload via [file.upload](https://open.manus.ai/docs/v2/file.upload) and pass the `file_id` in the message content, or use `file_url` / `file_data` directly. There is no hard limit on the number of attachments.
**Connectors:** Control this task's connectors with `message.connectors` and the top-level `clear_connectors` flag (three states):
* **Override** — pass a non-empty `message.connectors` to replace the task's connectors with the new list. Get IDs from [connector.list](https://open.manus.ai/docs/v2/connector.list) or the [Connectors](https://open.manus.ai/docs/v2/connectors) guide.
* **Clear** — pass `clear_connectors: true` to remove all connectors from the task.
* **Reuse** (default) — omit both to keep the connectors configured at [task.create](https://open.manus.ai/docs/v2/task.create) time.
Passing a non-empty `message.connectors` together with `clear_connectors: true` returns `InvalidArgument`.
**Enable skills:** Pass skill IDs from [skill.list](https://open.manus.ai/docs/v2/skill.list) in `message.enable_skills` to control which skills are available for the agent. If omitted, the user's default enabled skills are loaded automatically.
**Force skills:** Pass skill IDs in `message.force_skills` to ensure the agent invokes them. Forced skills are automatically available even if not listed in `enable_skills`.
**Reference existing tasks:** Pass task IDs in `message.task_references` (up to 20 per request) to let the agent browse those tasks on demand. Unlike connectors, references **accumulate** — see the warning below. Note that this field takes bare 22-character task IDs only: the `agent-default-main_task` shortcut above is valid as `task_id` but not as a reference, and neither is a full task URL.
**Waiting events:** Use this endpoint to reply when the agent asks a question (`messageAskUser`). For other waiting types like `gmailSendAction` or `deployAction`, use [task.confirmAction](https://open.manus.ai/docs/v2/task.confirmAction) instead.
**Task references accumulate; they cannot be replaced or cleared.** IDs passed here are added to the references the task already has. Sending `["B"]` to a task that already references `A` leaves it referencing both. An empty array is a no-op, and there is no `clear_task_references` counterpart to `clear_connectors`.
The 20-item cap applies per request. A task accumulating more than 20 references across several messages keeps the 20 most recently referenced and drops the oldest.
**Malformed input does fail the request.** Every entry must be a bare 22-character alphanumeric task ID; anything else — a full task URL, or the `agent-default-main_task` shortcut — returns `InvalidArgument` (HTTP 400). More than 20 entries in one request fails the same way, and that cap is applied to the array as sent, *before* duplicates and the self-reference are removed.
**Referencing a task you cannot open, however, does not fail the request.** Access is checked when the agent reads a reference, not when you send it. A task that does not exist, or that your account cannot open, is reported to the agent as not found — the agent continues without it. This is deliberate: failing at request time would let anyone probe which task IDs exist.
The one exception is an OAuth App holding only the `create_task` scope. It can reference only tasks it created itself, and gets `404` at request time otherwise.
A reference to the target task itself is silently dropped.
**Attachment size limits** depend on how you reference the file:
* `file_id` — a file pre-uploaded via [file.upload](https://open.manus.ai/docs/v2/file.upload). No additional limit here; it is bound only by the upload limits (≤ **512 MB** per file).
* `file_url` — a direct URL that Manus downloads. Capped at **20 MB**.
* `file_data` — inline base64 content. Capped at **20 MB** after decoding (\~26.7 MB of base64 text).
These are two different paths: large files must be uploaded via [file.upload](https://open.manus.ai/docs/v2/file.upload) first and referenced by `file_id`. Inline `file_url` / `file_data` attachments cannot exceed 20 MB.
## OpenAPI
````yaml POST /v2/task.sendMessage
openapi: 3.1.0
info:
title: Manus OpenAPI v2
description: >-
API for integrating Manus into your workflow. All responses are wrapped with
{"ok": true, "request_id": "...", ...} for success and {"ok": false,
"request_id": "...", "error": {"code": "...", "message": "..."}} for errors.
version: 2.0.0
servers:
- url: https://api.manus.ai
security:
- ApiKeyAuth: []
paths:
/v2/task.sendMessage:
post:
summary: SendMessage
description: >-
Sends a follow-up message to a task for multi-turn conversation. Use
this after [task.create](https://open.manus.ai/docs/v2/task.create) to
continue talking, or to reply when `waiting_for_event_type` is
`messageAskUser`. For other waiting types, use
[task.confirmAction](https://open.manus.ai/docs/v2/task.confirmAction)
instead.
operationId: openapi.v2.OpenapiV2Service.SendMessage
parameters:
- name: x-manus-api-key
in: header
required: false
schema:
type: string
description: >-
API key for direct authentication. Provide either this or
`Authorization`, not both. See
[Authentication](https://open.manus.ai/docs/v2/authentication).
- name: Authorization
in: header
required: false
schema:
type: string
example: Bearer {access_token}
description: >-
OAuth2 access token in `Bearer {token}` format. Provide either this
or `x-manus-api-key`, not both. See the [Open
App](https://open.manus.ai/docs/v2/open-app) guide.
requestBody:
required: true
content:
application/json:
schema:
type: object
properties:
task_id:
type: string
description: >-
The unique identifier of the task to send the message to.
Supports the shortcut `agent-default-main_task` for the IM
agent's main task.
message:
$ref: '#/components/schemas/Message'
description: >-
The follow-up message. Supports the same content formats as
task.create (plain text or multi-part with files). Note:
`message.connectors` behaves differently here than in
task.create — a non-empty list overrides the task's
connectors, while omitting it (or passing an empty array)
reuses the connectors configured at task.create time rather
than re-resolving project/user defaults. To remove all
connectors, use the top-level `clear_connectors` field
instead.
agent_profile:
type: string
enum:
- manus-1.6
- manus-1.6-lite
- manus-1.6-max
description: >-
Agent profile to use for this turn. "manus-1.6" — standard
capability. "manus-1.6-lite" — lightweight, faster
responses. "manus-1.6-max" — maximum capability. Omit (or
pass empty string) to keep the task's current profile; this
endpoint does not default to `manus-1.6` like
[task.create](https://open.manus.ai/docs/v2/task.create)
does. Free personal accounts are downgraded to
`manus-1.6-lite` regardless of the requested value.
structured_output_schema:
type: object
description: >-
JSON Schema for structured output extraction. Arms the
schema for the next time this task finishes (`stop_reason:
finish`). Sending a new schema replaces any previous one.
Omitting this field leaves the current schema state
unchanged — it does not clear an armed schema. See the
[Structured
Output](https://open.manus.ai/docs/v2/structured-output)
guide.
clear_connectors:
type: boolean
description: >-
Removes all connectors from this task for this and
subsequent turns. Combine with `message.connectors` to form
three states: a non-empty `message.connectors` **overrides**
the task's connectors with the new list; `clear_connectors:
true` **clears** all connectors; omitting both **reuses**
the connectors configured at task.create time. Passing a
non-empty `message.connectors` together with
`clear_connectors: true` is a conflict and returns
`InvalidArgument`.
default: false
required:
- task_id
- message
responses:
'200':
description: Message sent successfully. The task will resume processing.
content:
application/json:
schema:
type: object
properties:
ok:
type: boolean
example: true
description: Whether the request was successful.
request_id:
type: string
description: Unique identifier for this API request.
task_id:
type: string
description: The ID of the task the message was sent to.
4XX:
description: Error response.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
security: []
components:
schemas:
Message:
type: object
description: A message to send to a task.
properties:
content:
description: >-
String (plain text) or array of ContentPart objects. User text is
limited to approximately 5,000 estimated tokens per request; the
exact character count varies by language and content. For an array,
the limit applies to the combined text of all text parts; file parts
do not count. Input over the limit returns InvalidArgument (HTTP
400).
oneOf:
- type: array
items:
$ref: '#/components/schemas/ContentPart'
- type: string
connectors:
type: array
items:
type: string
description: >-
List of connector IDs to enable for this task. Resolution order when
omitted: 1) if the task belongs to a project, the project's default
connectors are used; 2) otherwise, the user's default enabled
connectors are used. Use
[connector.list](https://open.manus.ai/docs/v2/connector.list) to
get the connectors installed in your account.
enable_skills:
type: array
items:
type: string
description: >-
Skill IDs to enable for this task. If empty or omitted, loads the
skills the user has enabled in their account settings. Use
[skill.list](https://open.manus.ai/docs/v2/skill.list) to retrieve
available skill IDs.
force_skills:
type: array
items:
type: string
description: >-
Skill IDs the agent must invoke during this task. Forced skills are
automatically available even if not listed in enable_skills.
task_references:
type: array
items:
type: string
pattern: ^[A-Za-z0-9]{22}$
maxItems: 20
description: >-
Task IDs of existing tasks to reference from this message. The agent
can then browse the conversation and files of those tasks on demand.
Each entry must be a bare 22-character alphanumeric task ID — a full
task URL, or a shortcut value such as `agent-default-main_task`, is
rejected. Validated at request time: any malformed ID, or more than
20 entries, fails with `InvalidArgument` (HTTP 400). The 20-item cap
is applied to the array as sent, before duplicates are removed, so
21 entries fail even if some repeat. References accumulate: IDs
passed to
[task.sendMessage](https://open.manus.ai/docs/v2/task.sendMessage)
are added to the references the task already has, and an empty array
does not clear them. Duplicates are dropped, and so is a
self-reference on task.sendMessage. Beyond those request-time
checks, access is enforced when the agent reads a reference, not
when you send it: a task you cannot open is reported to the agent as
not found and your request still succeeds. One exception: an OAuth
App that holds only the create_task scope can reference only tasks
it created itself, and gets 404 at request time otherwise.
required:
- content
ErrorResponse:
type: object
description: Standard error response format returned when a request fails.
properties:
ok:
type: boolean
example: false
description: Always false for error responses.
request_id:
type: string
description: >-
Unique identifier for this API request, useful for debugging with
support.
error:
type: object
description: Error details.
properties:
code:
type: string
description: >-
Machine-readable error code (e.g., "invalid_argument",
"not_found", "permission_denied", "rate_limited").
message:
type: string
description: Human-readable error description explaining what went wrong.
ContentPart:
oneOf:
- type: object
title: Text
properties:
type:
type: string
enum:
- text
description: Must be "text".
text:
type: string
description: >-
The text content of the message. Across a ContentPart array, all
text parts must contain no more than approximately 5,000
estimated tokens in total.
required:
- type
- text
- type: object
title: File
description: '**Provide the file via one of: file_id, file_url, or file_data.**'
properties:
type:
type: string
enum:
- file
description: Must be "file".
file_id:
type: string
description: >-
ID of a previously uploaded file. Upload via
[file.upload](https://open.manus.ai/docs/v2/file.upload) first
to get the file ID.
file_url:
type: string
description: >-
Publicly accessible URL to the file. The agent will download it
directly.
file_data:
type: string
description: >-
Base64 encoded file content. Format:
`data:;base64,` (e.g.,
`data:application/pdf;base64,JVBERi0...`).
filename:
type: string
description: >-
Display name of the file including extension (e.g.,
"report.pdf"). Required when using file_data; recommended for
file_url.
mime_type:
type: string
description: >-
MIME type of the file (e.g., "application/pdf", "image/png").
Optional; auto-detected from filename if omitted.
required:
- type
- type: object
title: Voice
description: '**Provide the audio via one of: file_id, file_url, or file_data.**'
properties:
type:
type: string
enum:
- voice
description: Must be "voice".
file_id:
type: string
description: >-
ID of a previously uploaded audio file. Upload via
[file.upload](https://open.manus.ai/docs/v2/file.upload) first
to get the file ID.
file_url:
type: string
description: >-
Publicly accessible URL to the audio file. The agent will
download and transcribe it.
file_data:
type: string
description: >-
Base64 encoded audio content. Format:
`data:;base64,` (e.g.,
`data:audio/wav;base64,UklGRi...`).
filename:
type: string
description: >-
Display name of the audio file including extension (e.g.,
"recording.wav"). Required when using file_data.
mime_type:
type: string
description: >-
MIME type of the audio file (e.g., "audio/wav", "audio/mp3").
Optional; auto-detected from filename if omitted.
required:
- type
securitySchemes:
ApiKeyAuth:
type: apiKey
in: header
name: x-manus-api-key
````