Tools

Signal MCP exposes the following MCP tools:

`send`

Send a message to the channel operator's phone. No phone number needed — this uses the --operator configured at startup.

Parameter	Type	Required	Description
`message`	`str`	Yes	The message to send

send(message="Hey, the deploy is done!")

`send_message_to_user`

Send a direct message to a specific Signal user.

Parameter	Type	Required	Description
`message`	`str`	Yes	The message to send
`user_id`	`str`	Yes	Recipient phone number (e.g. `+15551234567`)

send_message_to_user(message="Hello!", user_id="+15551234567")

`send_message_to_group`

Send a message to a Signal group. The group_id can be the group's internal ID or its display name.

Parameter	Type	Required	Description
`message`	`str`	Yes	The message to send
`group_id`	`str`	Yes	Group internal ID or display name

send_message_to_group(message="Team update", group_id="#dev-team")

`send_reaction_to_user`

React to a user's message with an emoji.

Parameter	Type	Required	Description
`emoji`	`str`	Yes	The emoji to react with
`user_id`	`str`	Yes	Recipient phone number
`target_author`	`str`	Yes	Author of the message being reacted to
`target_timestamp`	`int`	Yes	Timestamp of the target message
`remove`	`bool`	No	Set `True` to remove a reaction (default: `False`)

send_reaction_to_user(
    emoji="👍",
    user_id="+15551234567",
    target_author="+15551234567",
    target_timestamp=1744185565466,
)

`send_reaction_to_group`

React to a message in a group with an emoji.

Parameter	Type	Required	Description
`emoji`	`str`	Yes	The emoji to react with
`group_id`	`str`	Yes	Group internal ID or display name
`target_author`	`str`	Yes	Author of the message being reacted to
`target_timestamp`	`int`	Yes	Timestamp of the target message
`remove`	`bool`	No	Set `True` to remove a reaction (default: `False`)

`receive_message`

Wait for and receive the next actionable message (text or reaction) within a timeout. Messages that arrived while the daemon was streaming are queued, so back-to-back calls won't drop anything.

Parameter	Type	Required	Description
`timeout`	`float`	No	Seconds to wait (default: `60`)

Returns a MessageResponse with either:

Text message: message, sender_id, sender_name, group_id, timestamp
Reaction: reaction (emoji, target_author, target_timestamp, is_remove)
Timeout: empty response (all fields None)

result = await receive_message(timeout=30.0)
if result.message:
    print(f"Got: {result.message} from {result.sender_id}")
elif result.reaction:
    print(f"Got reaction: {result.reaction.emoji}")

`mark_read`

Mark a received message as read in Signal. In channel mode this happens automatically when a message is forwarded. In normal (polling) mode, call this after receive_message to send a read receipt.

Parameter	Type	Required	Description
`sender`	`str`	Yes	Sender phone number (from `sender_id` in the received message)
`target_timestamp`	`int`	Yes	Message timestamp (from `timestamp` in the received message)

result = await mark_read(
    sender="+15551234567",
    target_timestamp=1744185565466,
)

send​

send_message_to_user​

send_message_to_group​

send_reaction_to_user​

send_reaction_to_group​

receive_message​

mark_read​