MCP Reference

chat_send_message

Send Chat Message

Beschreibung

Posts a message to a chat channel or DM — optionally with file attachments (images, PDFs, video, any MIME type). Synchronous: hits the DB and Turbo-broadcasts to members before returning.

Body is GFM Markdown, ≤ 32 KB. @handle mentions resolve against active account members; response's mentions echoes what mapped (resolve handles via account_list_users).
attachment_ids entries come from attachment_upload — pass the att_… id or the file_url, either works. Body becomes optional when at least one attachment is present.
parent_message_id threads the post (single-level only).
Not idempotent — retries create duplicate rows.
Workspace members can post to public channels and their threads without joining the channel. Private channels and DMs require channel membership; account admins retain tenant-wide access.

Zugriff

Zugriffsprofil: basic. Module: chat. Die Freigabe im Profil ersetzt keine Account-, Workspace- oder Rollenberechtigung.

Parameter

Name	Typ	Pflicht	Beschreibung
`account_id`	string	Ja	Account prefix ID (e.g., acct_abc123).
`channel_id`	string	Ja	Channel prefix ID (e.g., chan_xyz789) from chat_list_channels.
`body`	string	Nein	Markdown content. Do not escape the string — use literal newlines and special characters, not escape sequences. Supports GFM plus @handle mentions (resolved against active account members). Max 32 KB. Optional when attachment_ids is present.
`parent_message_id`	string	Nein	Thread this reply under this root message's prefix ID (msg_…). Single-level threading only — replies to replies are rejected.
`attachment_ids`	array	Nein	Attachment handles from attachment_upload — att_… ids or file_urls, mixed freely. Each blob may only be attached to one chat message. Body may be empty when at least one attachment is present.

Eingabeschema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "account_id": {
      "type": "string",
      "description": "Account prefix ID (e.g., acct_abc123)."
    },
    "channel_id": {
      "type": "string",
      "description": "Channel prefix ID (e.g., chan_xyz789) from chat_list_channels."
    },
    "body": {
      "type": "string",
      "maxLength": 32768,
      "description": "Markdown content. Do not escape the string — use literal newlines and special characters, not escape sequences. Supports GFM plus @handle mentions (resolved against active account members). Max 32 KB. Optional when attachment_ids is present."
    },
    "parent_message_id": {
      "type": "string",
      "description": "Thread this reply under this root message's prefix ID (msg_…). Single-level threading only — replies to replies are rejected."
    },
    "attachment_ids": {
      "type": "array",
      "maxItems": 20,
      "items": {
        "type": "string"
      },
      "description": "Attachment handles from attachment_upload — att_… ids or file_urls, mixed freely. Each blob may only be attached to one chat message. Body may be empty when at least one attachment is present."
    }
  },
  "required": [
    "account_id",
    "channel_id"
  ],
  "type": "object"
}

Ausgabeschema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "message": {
      "type": "object",
      "properties": {
        "id": {
          "type": "string",
          "description": "Message prefix ID (msg_…)."
        },
        "body": {
          "type": "string"
        },
        "user": {
          "type": "object",
          "properties": {
            "id": {
              "type": [
                "string",
                "null"
              ]
            },
            "handle": {
              "type": [
                "string",
                "null"
              ]
            },
            "name": {
              "type": "string"
            }
          }
        },
        "created_at": {
          "type": "string",
          "format": "date-time"
        },
        "parent_message_id": {
          "type": [
            "string",
            "null"
          ]
        },
        "replies_count": {
          "type": "integer"
        },
        "mentions": {
          "type": "object",
          "description": "Server-side resolution of @handle tokens in body — confirms what you intended actually mapped.",
          "properties": {
            "resolved_users": {
              "type": "array",
              "items": {
                "type": "object",
                "properties": {
                  "id": {
                    "type": "string"
                  },
                  "handle": {
                    "type": "string"
                  },
                  "name": {
                    "type": "string"
                  }
                }
              }
            },
            "mention_all": {
              "type": "boolean",
              "description": "True when `@all` was used."
            }
          }
        },
        "reactions": {
          "type": "array",
          "description": "Always an empty array on a freshly-sent message — here for shape parity with chat_get_messages.",
          "items": {
            "type": "object"
          }
        },
        "attachments": {
          "type": "array",
          "description": "Files attached to this message (via attachment_ids). Same shape as chat_get_messages.",
          "items": {
            "type": "object",
            "properties": {
              "id": {
                "type": "string"
              },
              "filename": {
                "type": "string"
              },
              "mime_type": {
                "type": "string"
              },
              "byte_size": {
                "type": "integer"
              },
              "download_url": {
                "type": "string",
                "format": "uri",
                "description": "Signed URL, valid 30 minutes."
              },
              "created_at": {
                "type": "string",
                "format": "date-time"
              }
            }
          }
        }
      },
      "required": [
        "id",
        "body",
        "user",
        "created_at",
        "parent_message_id",
        "replies_count",
        "mentions",
        "reactions",
        "attachments"
      ]
    }
  },
  "required": [
    "message"
  ],
  "type": "object"
}