Implementation:Wandb Weave Prompt Ref Get

Knowledge Sources	Wandb Weave Weave Docs
Domains	Prompt_Engineering, Object_Storage
Last Updated	2026-02-14 00:00 GMT

Overview

Concrete tool for retrieving published prompts and formatting them with variables provided by the Wandb Weave library.

Description

weave.ref() creates an ObjectRef pointing to a published prompt. ref.get() deserializes it. prompt.format(**kwargs) applies template variable substitution. The format_message_with_template_vars helper recursively processes nested message content.

Usage

Use weave.ref("prompt_name").get() to load a published prompt, then call .format() with your template variables.

Code Reference

Source Location

• Repository: wandb/weave
• File: weave/trace/api.py
• Lines: L181-207 (ref)
• File: weave/prompt/prompt.py
• Lines: L96-97 (StringPrompt.format), L180-181 (MessagesPrompt.format), L108-161 (format_message_with_template_vars)

Signature

def ref(location: str) -> ObjectRef:
    """Creates a Ref to an existing Weave object.

    Args:
        location: URI, "name:version", or "name" (resolves to latest).

    Returns:
        ObjectRef to the prompt.
    """

# Then call:
# prompt = ref.get()  # Deserializes the Prompt object
# result = prompt.format(**kwargs)  # Applies variable substitution

Import

import weave

I/O Contract

Inputs

Name	Type	Required	Description
location	str	Yes	Prompt name, "name:version", or full URI
**kwargs	Any	Varies	Template variables for format()

Outputs

Name	Type	Description
ref.get()	Prompt	Deserialized Prompt object
prompt.format()	str or list	Formatted prompt with variables substituted

Usage Examples

Retrieve and Format

import weave

weave.init("my-team/my-project")

# Load latest version
prompt = weave.ref("translation_prompt").get()
result = prompt.format(text="Hello", language="French")
print(result)

# Load specific version
prompt_v1 = weave.ref("translation_prompt:abc123").get()

Related Pages

Implements Principle

• Principle:Wandb_Weave_Prompt_Retrieval

Requires Environment

• Environment:Wandb_Weave_Python_SDK_Runtime