VAPI•7mo ago

Change assistantOverrides variableValues via PATCH /call while call is in progress

Tried setting variableValues on an incoming call but it doesn't seem to work.

Am trying to send the caller a text, get some info from them, then update them with the new info live on the call.

Is this possible? Looks like it's not but thought I'd ask!

Vapi Support BotAPP•5/27/25, 11:13 PM

You cannot update
assistantOverrides
assistantOverrides
or
variableValues
variableValues
via PATCH /call while a call is in progress.
The error you received ("property assistantOverrides should not exist""property assistantOverrides should not exist") matches the API documentation, which does not support this property for live call updates. Currently, dynamic variables must be set when the call is initiated, not during the call.

If you need to update assistant variables mid-call, this is not supported by the current Vapi API.

Sources:

⤵️ Mention @Vapi Support Bot for follow-ups 🐥

Vapi Support BotAPP•5/27/25, 11:14 PM

You cannot update
assistantOverrides
assistantOverrides
or
variableValues
variableValues
via PATCH /call while a call is in progress. The API only allows these to be set when the call is created, not updated during the call. The error you received is expected based on the current API documentation—live variable updates are not supported at this time.

Sources:

VVapi Support Bot **You cannot update `assistantOverrides` or `variableValues` via PATCH /call whi...

DuckieAPP•5/27/25, 11:31 PM

Message marked as helpful by @Hugh Fungus!

moderate-tomatoOP•5/27/25, 11:32 PM

Shame, the voice support assistant on the docs must've hallucinated again

VVapi Support Bot **You cannot update `assistantOverrides` or `variableValues` via PATCH /call whi...

DuckieAPP•5/27/25, 11:33 PM

Message marked as helpful by @Hugh Fungus!

moderate-tomatoOP•5/27/25, 11:34 PM

@Duckie so I suppose there's no way at all that you can update a call that's in progress via a web hook or anything else?

Vapi Support BotAPP•5/27/25, 11:34 PM

Live updates to
assistantOverrides
assistantOverrides
or
variableValues
variableValues
during a call are not supported by the Vapi API.
You can only set these variables when the call is created, not via PATCH /callPATCH /call while the call is in progress.
For more details, see the Vapi API Reference and Dynamic Variables documentation.

Sources:

Vapi Support BotAPP•5/27/25, 11:35 PM

No, you cannot update assistant variables (like
assistantOverrides
assistantOverrides
or
variableValues
variableValues
) for a call in progress via PATCH, webhook, or any other method. These must be set when the call is created, and live updates are not supported by the current Vapi API. For real-time interaction, you can use live call control features (like injecting messages), but not variable updates.

See: Vapi Personalization Documentation

Sources:

KyleAPP•5/28/25, 6:43 AM

checking if this is resolved/solved for you?

Ccomprehensive-tomato checking if this is resolved/solved for you?

moderate-tomatoOP•5/28/25, 7:49 AM

Hey! Bots are indicating it isn't possible but no humans have confirmed yet

Vapi Support BotAPP•5/28/25, 7:51 AM

Human confirmation:
Based on the official Vapi documentation, there is currently no way to update
assistantOverrides
assistantOverrides
or
variableValues
variableValues
for a call in progress—not via PATCH, webhook, or any other method. These must be set at call creation, and live updates are not supported. For real-time interaction, you can only inject messages (not update variables) during the call.

See: Vapi Personalization Documentation | Vapi API Reference: Update Call

Sources:

Vapi Support BotAPP•5/28/25, 7:51 AM

Human confirmation:
There is no supported way to update
assistantOverrides
assistantOverrides
or
variableValues
variableValues
for a call in progress—not via PATCH, webhook, or any other method. These variables must be set when the call is created, and live updates are not possible according to all official Vapi documentation.
If you need dynamic behavior mid-call, consider using message injection or other live call control features, but variable updates are not supported.

References:

Sources:

KyleAPP•5/29/25, 1:18 AM

Hi Hugh Fungus,

It sounds like you want to use live call control to inject a message during your calls. You can add a message with the role of "system" to update your live call with the new dynamic values. Make sure to include the instructions on how to use those values during the call. I recommend giving it a couple of tries and let me know how it goes.

Change assistantOverrides variableValues via PATCH /call while call is in progress

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