# 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)

## message_heyreach

Reply in an existing LinkedIn conversation as one of the workspace's senders, or mark a conversation seen or unseen.

Use to send a reply a person has approved into a thread returned by read_heyreach, naming the sender account that owns the conversation.

A sent LinkedIn message reaches a real person and cannot be recalled; it is refused on a frozen subscription. The server deduplicates retries of the same send. Marking seen sends nothing and is always available.

Obtain the user's explicit authorization before invoking a write or destructive action. This is a client interaction requirement, not a server-issued approval token.

Scopes: integration:update, unibox:reply

Risk: costly; confirmation: explicit; idempotency: supported.

### Input schema (personal API key)

```json
{
  "type": "object",
  "anyOf": [
    {
      "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})$",
          "format": "uuid"
        },
        "conversationId": {
          "$ref": "#/$defs/HeyReachConversationId"
        },
        "action": {
          "type": "string",
          "enum": [
            "send"
          ]
        },
        "send": {
          "$ref": "#/$defs/SendHeyReachMessageInput"
        }
      },
      "required": [
        "workspaceId",
        "conversationId",
        "action",
        "send"
      ],
      "patternProperties": {
        "^(?!(?:workspaceId|conversationId|action|send)$)[\\s\\S]*$": false
      },
      "additionalProperties": true,
      "propertyNames": {
        "type": "string",
        "enum": [
          "workspaceId",
          "conversationId",
          "action",
          "send"
        ]
      }
    },
    {
      "type": "object",
      "properties": {
        "workspaceId": {
          "type": "string",
          "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|[fF]{8}-[fF]{4}-[fF]{4}-[fF]{4}-[fF]{12})$",
          "format": "uuid"
        },
        "conversationId": {
          "$ref": "#/$defs/HeyReachConversationId"
        },
        "action": {
          "type": "string",
          "enum": [
            "mark_seen"
          ]
        },
        "seen": {
          "$ref": "#/$defs/SetHeyReachSeenInput"
        }
      },
      "required": [
        "workspaceId",
        "conversationId",
        "action",
        "seen"
      ],
      "patternProperties": {
        "^(?!(?:workspaceId|conversationId|action|seen)$)[\\s\\S]*$": false
      },
      "additionalProperties": true,
      "propertyNames": {
        "type": "string",
        "enum": [
          "workspaceId",
          "conversationId",
          "action",
          "seen"
        ]
      }
    }
  ],
  "$defs": {
    "HeyReachConversationId": {
      "type": "string",
      "minLength": 1,
      "maxLength": 2000
    },
    "HeyReachId": {
      "type": "integer",
      "exclusiveMinimum": 0,
      "maximum": 9007199254740991
    },
    "SendHeyReachMessageInput": {
      "type": "object",
      "properties": {
        "linkedInAccountId": {
          "$ref": "#/$defs/HeyReachId"
        },
        "message": {
          "type": "string",
          "minLength": 1,
          "maxLength": 8000
        },
        "subject": {
          "type": "string",
          "minLength": 0,
          "maxLength": 200
        }
      },
      "required": [
        "linkedInAccountId",
        "message"
      ],
      "patternProperties": {
        "^(?!(?:linkedInAccountId|message|subject)$)[\\s\\S]*$": false
      },
      "additionalProperties": true,
      "propertyNames": {
        "type": "string",
        "enum": [
          "linkedInAccountId",
          "message",
          "subject"
        ]
      }
    },
    "SetHeyReachSeenInput": {
      "type": "object",
      "properties": {
        "linkedInAccountId": {
          "$ref": "#/$defs/HeyReachId"
        },
        "seen": {
          "type": "boolean"
        }
      },
      "required": [
        "linkedInAccountId",
        "seen"
      ],
      "patternProperties": {
        "^(?!(?:linkedInAccountId|seen)$)[\\s\\S]*$": false
      },
      "additionalProperties": true,
      "propertyNames": {
        "type": "string",
        "enum": [
          "linkedInAccountId",
          "seen"
        ]
      }
    }
  }
}
```

### Input schema (OAuth / delegated agent)

```json
{
  "type": "object",
  "properties": {
    "workspaceId": {
      "type": "string",
      "format": "uuid",
      "description": "Target Workspace UUID. Call list_workspaces to enumerate the Workspaces this credential may access, then pass the chosen id here."
    }
  },
  "required": [
    "workspaceId"
  ],
  "anyOf": [
    {
      "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})$",
          "format": "uuid"
        },
        "conversationId": {
          "$ref": "#/$defs/HeyReachConversationId"
        },
        "action": {
          "type": "string",
          "enum": [
            "send"
          ]
        },
        "send": {
          "$ref": "#/$defs/SendHeyReachMessageInput"
        }
      },
      "required": [
        "workspaceId",
        "conversationId",
        "action",
        "send"
      ],
      "patternProperties": {
        "^(?!(?:workspaceId)$)[\\s\\S]*?(?:^(?!(?:workspaceId|conversationId|action|send)$)[\\s\\S]*$)": false
      },
      "additionalProperties": true,
      "propertyNames": {
        "anyOf": [
          {
            "type": "string",
            "enum": [
              "workspaceId",
              "conversationId",
              "action",
              "send"
            ]
          },
          {
            "enum": [
              "workspaceId"
            ]
          }
        ]
      }
    },
    {
      "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})$",
          "format": "uuid"
        },
        "conversationId": {
          "$ref": "#/$defs/HeyReachConversationId"
        },
        "action": {
          "type": "string",
          "enum": [
            "mark_seen"
          ]
        },
        "seen": {
          "$ref": "#/$defs/SetHeyReachSeenInput"
        }
      },
      "required": [
        "workspaceId",
        "conversationId",
        "action",
        "seen"
      ],
      "patternProperties": {
        "^(?!(?:workspaceId)$)[\\s\\S]*?(?:^(?!(?:workspaceId|conversationId|action|seen)$)[\\s\\S]*$)": false
      },
      "additionalProperties": true,
      "propertyNames": {
        "anyOf": [
          {
            "type": "string",
            "enum": [
              "workspaceId",
              "conversationId",
              "action",
              "seen"
            ]
          },
          {
            "enum": [
              "workspaceId"
            ]
          }
        ]
      }
    }
  ],
  "$defs": {
    "HeyReachConversationId": {
      "type": "string",
      "minLength": 1,
      "maxLength": 2000
    },
    "HeyReachId": {
      "type": "integer",
      "exclusiveMinimum": 0,
      "maximum": 9007199254740991
    },
    "SendHeyReachMessageInput": {
      "type": "object",
      "properties": {
        "linkedInAccountId": {
          "$ref": "#/$defs/HeyReachId"
        },
        "message": {
          "type": "string",
          "minLength": 1,
          "maxLength": 8000
        },
        "subject": {
          "type": "string",
          "minLength": 0,
          "maxLength": 200
        }
      },
      "required": [
        "linkedInAccountId",
        "message"
      ],
      "patternProperties": {
        "^(?!(?:linkedInAccountId|message|subject)$)[\\s\\S]*$": false
      },
      "additionalProperties": true,
      "propertyNames": {
        "type": "string",
        "enum": [
          "linkedInAccountId",
          "message",
          "subject"
        ]
      }
    },
    "SetHeyReachSeenInput": {
      "type": "object",
      "properties": {
        "linkedInAccountId": {
          "$ref": "#/$defs/HeyReachId"
        },
        "seen": {
          "type": "boolean"
        }
      },
      "required": [
        "linkedInAccountId",
        "seen"
      ],
      "patternProperties": {
        "^(?!(?:linkedInAccountId|seen)$)[\\s\\S]*$": false
      },
      "additionalProperties": true,
      "propertyNames": {
        "type": "string",
        "enum": [
          "linkedInAccountId",
          "seen"
        ]
      }
    }
  }
}
```

### Output schema (structuredContent)

```json
{
  "type": "object",
  "properties": {
    "success": {
      "type": "boolean",
      "enum": [
        true
      ]
    }
  },
  "required": [
    "success"
  ],
  "patternProperties": {
    "^(?!(?:success)$)[\\s\\S]*$": false
  },
  "additionalProperties": true,
  "propertyNames": {
    "anyOf": [
      {
        "type": "string",
        "enum": [
          "success"
        ]
      }
    ]
  }
}
```

### Underlying API operations

- `heyreachConversations.send`: `POST /v1/workspaces/:workspaceId/integrations/heyreach/conversations/:conversationId/messages`
- `heyreachConversations.seen`: `POST /v1/workspaces/:workspaceId/integrations/heyreach/conversations/:conversationId/seen`