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ctx (Metadata Access)

The ctx object provides access to metadata about the current prompt execution.

Viewing All Metadata​

Render {{ ctx }} to see all available metadata in the playground preview.

Available Properties​

PropertyDescription
ctx.output_formatOutput schema generator
ctx.clientCurrent client information
ctx.client.providerProvider name (e.g., "anthropic", "openai")

Conditional Rendering by Provider​

Customize prompts based on the LLM provider:

template_string RenderConditionally(messages: Message[]) #"
    {% for message in messages %}
        {% if ctx.client.provider == "anthropic" %}
            <Message>{{ message.user_name }}: {{ message.content }}</Message>
        {% else %}
            {{ message.user_name }}: {{ message.content }}
        {% endif %}
    {% endfor %}
"#

function MyFuncWithGPT4(messages: Message[]) -> string {
    client "openai/gpt-4o"
    prompt #"
        {{ RenderConditionally(messages) }}
    "#
}

function MyFuncWithAnthropic(messages: Message[]) -> string {
    client "anthropic/claude-sonnet-4-20250514"
    prompt #"
        {{ RenderConditionally(messages) }}
    "#
}

This example uses XML tags for Anthropic (as recommended by their documentation) and plain text for other providers.

Use Cases​

  • Provider-specific formatting: XML tags for Anthropic, markdown for OpenAI
  • Model-specific instructions: Different detail levels based on model capabilities
  • Debugging: Inspect metadata during development

See Also​