Unable to update an existing prompt in the vertex ai prompt library using python SDK.

[subbu4github]

I am using the following command to fetch the existing prompt from the library

existing_prompt = client.prompts.get(prompt_id="12356644445433333")

I am using the below command to update its content

existing_prompt.prompt_data = types.PromptData(
contents=[
genai_types.Content(
parts=[genai_types.Part(text=content)]
)
],
model=MODEL
)

After the above modification I verified that prompt id is intact by using the following command

print(f"After modification {existing_prompt.prompt_id}")

I used the following command to create the version for the prompt.

version = client.prompts.create_version(prompt=existing_prompt) #since prompt id is deprecated, I am not passing it.

Instead of updating the existing prompt, its creating a newer prompt with the updated content. How to fix this.

The following packages are utilized

import vertexai
from google.genai import types as genai_types
from vertexai import types
from vertexai.preview.prompts import Prompt

-- Subbu S.

[barry166]

Pass the prompt id explicitly to create_version. Mutating the object returned by client.prompts.get() only changes a local Prompt; the SDK still needs prompt_id to know which prompt resource the new version belongs under.

prompt_id = "12356644445433333"

existing_prompt = client.prompts.get(prompt_id=prompt_id)
existing_prompt.prompt_data = types.PromptData(
    contents=[genai_types.Content(parts=[genai_types.Part(text=content)])],
    model=MODEL,
)

version = client.prompts.create_version(
    prompt=existing_prompt,
    prompt_id=prompt_id,
)

The current Agent Platform prompt management docs still show create_version(prompt=prompt, prompt_id=...), and note that changes to a Prompt object are local until create or create_version is called. If your IDE marks a Prompt.prompt_id property as deprecated, that is separate from the create_version target id argument. I would also avoid mixing the old vertexai.preview.prompts.Prompt surface with vertexai.Client prompt management in the same flow; use the vertexai.Client / vertexai.types path consistently.

Docs: https://docs.cloud.google.com/gemini-enterprise-agent-platform/reference/models/prompt-classes#save-a-prompt-to-a-google-cloud-project

[subbu4github]

@barry166 - This option is deprecated now. There is an alternate function provided for this purpose with the following signature

client.prompts.update(
prompt=prompt,
config=config,
prompt_id=PROMPT_ID
)

This is creating a revision for the existing prompt.