The full catalog of actions an agent can take during a conversation.
An action is a discrete operation an agent performs during a conversation: play a message, transfer the call, query a knowledge base, run a workflow, and more. Actions never run on their own. They are grouped into a tool that the LLM decides to call, so the model controls when an ability fires while the configuration controls what it does.
A tool (ToolCall) exposes a single function to the LLM. When the model calls it, the agent runs the tool’s ordered list of actions, then renders an output the model can read back.
Field
Type
Default
Description
name
string
required
Function name the LLM invokes.
description
string
required
When to call the tool. The model uses this to decide.
properties
object
{}
JSON-Schema-style argument definitions the LLM fills in.
required
string[]
[]
Argument names that must be supplied.
actions
Action[]
required
Ordered list of actions run when the tool is called.
actions_on_error
Action[]
[]
Actions run if one of the main actions raises an error.
output
string
null
Template rendered and returned to the LLM after the actions run.
Actions execute in order. Each action whose condition passes runs; its result is merged into the tool’s data so later actions and the output template can reference it.
Every action carries an optional condition expression. When set, the action runs only if the expression evaluates truthy against the current tool-call data. Leave it empty to always run the action.
Actions form a discriminated union keyed on type. The full set:
type
Title
Purpose
play_message
Play Message
Speak or send a message to the contact.
cold_transfer
Cold Transfer
Hand the call to another number and drop off.
warm_transfer
Warm Transfer
Brief a supervisor, then connect them to the caller.
conference
Add to Conference
Add the call to a conference bridge.
dtmf
Send DTMF
Send touch-tone digits or letters.
hangup
Hangup
End the call.
leave_room
Leave Room
Remove the agent from the room.
wait
Wait
Pause for a number of seconds.
update_endpointing
Update Endpointing
Adjust turn-detection timing mid-call.
play_audio
Play Audio
Play an audio file (loopable).
stop_audio
Stop Audio
Stop a currently playing audio file.
workflow
Workflow
Run a workflow by reference or inline.
knowledge_base
Knowledge Base
Run a RAG query against a dataset.
Transfers, conferencing, and DTMF have their own page. See /agents/transfers for the call-routing actions (cold_transfer, warm_transfer, conference, dtmf).
Runs a workflow either by reference (workflow_id + workflow_version) or as an inline definition. The two sources are mutually exclusive.
Field
Type
Default
Description
workflow_id
string
null
ID of a saved workflow. Requires workflow_version.
workflow_version
int
null
Version of the saved workflow.
initial_step
string
null
Step to start at. Required when using a reference; defaults to trigger for inline definitions.
definition
object
null
Inline workflow definition. Mutually exclusive with workflow_id/workflow_version.
reject_on_error
bool
false
If true, abort the conversation when the workflow fails.
condition
string
null
Run only if this expression is truthy.
You must supply either workflow_id + workflow_version or a non-empty inline definition, but not both. When using a reference, initial_step is required.
The workflow runs synchronously. The tool-call arguments and conversation data are passed as input, and the workflow’s output (or its context if there is no output) becomes the action result.
The action catalog is built for telephony. On the async text and email engine there is no audio playout or call control, so only three action types execute:
Async text / email engine├── workflow ✓ runs├── knowledge_base ✓ runs├── play_message ✓ runs (returns the rendered text as output)└── everything else ✗ skipped with a warning
Action
Voice / telephony
Async text / email
play_message
✓
✓ (rendered text returned, no audio)
workflow
✓
✓
knowledge_base
✓
✓
cold_transfer
✓
skipped
warm_transfer
✓
skipped
conference
✓
skipped
dtmf
✓
skipped
hangup
✓
skipped
leave_room
✓
skipped
wait
✓
skipped
update_endpointing
✓
skipped
play_audio
✓
skipped
stop_audio
✓
skipped
On async channels, play_message has no audio playout. The rendered message text is returned as the action output so the tool’s output template can reference it. Any voice-only action is skipped and logged, not failed.
