Overview
The LLM block sends prompts to AI language models and returns generated text. Use it for content creation, summarization, analysis, or any text-based AI task.Configuration
Click the model bar at the top of the configuration panel to open the settings. The bar shows the selected model and output format.Model
Select the AI model in the Model dropdown. The dropdown lists the models currently available in Slate, and the list changes as new models are released. Default: GPT-5.4 mini Different models have different capabilities, speed, and cost. The settings below change based on the model you select.Output Format
Define how the model returns its response. Options:- Text: Plain text response
- JSON: Structured data response
Reasoning Effort
Controls how much reasoning the model applies before it answers. Higher effort can improve quality but takes longer. Available for: GPT models, Gemini 3 models, and DeepSeek modelsVerbosity
Controls how long and detailed the response is. Available for: GPT-5.x models Options: Low, Medium (default), HighStream Output
Streams the response to the UI in real time while the block runs. Turn Stream Output off for faster execution without a live preview. Default: Off for new LLM blocksEnable Thinking
Lets the model think before it responds. Available for: Anthropic models that support thinking (Sonnet, Opus, and Fable models) Enable Thinking turns on automatically when you select one of these models. When it’s on, use Thinking Effort to set how much effort the model puts into thinking: Max, High (default), Medium, or Low.System Instructions
Define the model’s role, tone, and behavior. Optional field that sets context for all messages in this block. Example:Enable Web Search
Allow the model to search the web for current information. Available for: GPT, Anthropic (Sonnet, Opus, and Fable), and Gemini models When enabled, the model can retrieve up-to-date information from the internet to answer your queries. Useful for queries requiring recent data, news, or facts beyond the model’s training cutoff. Perplexity models don’t show this toggle. See Perplexity models. Note: Web search increases response time and credit usage. If you combine web search with JSON output, describe the exact JSON shape in System Instructions. JSON output isn’t guaranteed when web search is on.Citations
Include source references in the model’s response. Requirements: For GPT, Anthropic, and Gemini models, turn on Enable Web Search, then select Include Citations. Choose a Citation Format:-
Include within the answer: Inline citations using [1], [2] format with a References section at the end
-
Separate answer and citations: JSON format with separate answer and citations fields
Allowed Domains
Limit web search results to specific domains. Requirements: Enable Web Search must be turned on Maximum: 20 domains The control depends on the model:- GPT models: Allowed Domains (Optional) limits search to the domains you list. Enter domains without the http:// or https:// prefix and without paths.
- Anthropic models: Domain Filtering has a Filter Mode of Include Only or Exclude. You can enter domains or full URLs.
- Correct:
wikipedia.org - Incorrect:
https://wikipedia.org
{{input.domain}}. Use domain filters to ensure responses cite only trusted or relevant sources for your use case.
Perplexity Models
Perplexity models have no Enable Web Search toggle. They always show these settings:- Include Citations: Adds source citations. With Text output, the response ends with numbered references. With JSON output, the response includes a citations array.
- Domain Filtering: Choose Include Only or Exclude in Filter Mode, then enter up to 20 domains or full URLs.
Messages
Define the conversation between user and assistant.User Message (Required)
The prompt sent to the AI model. This is where you reference placeholders and define your request. Example:{ } icon to insert placeholders from previous steps or inputs.
Click Add message to add another message. Click a message’s USER or ASSISTANT label to switch its role.
Assistant Message
Optional: Pre-fill the start of the assistant’s response to guide output format or structure. Example:Using Liquid Templating in Prompts
You can use Liquid templating syntax in your prompts to create dynamic, data-driven messages. Liquid lets you reference workflow data, apply filters, use loops, and add conditional logic directly in your prompts.Basic Variable Output
Reference previous step outputs:Using Filters
Transform data with filters:Loops in Prompts
Loop through arrays to build dynamic prompts:Conditional Logic
Adjust prompts based on data:Complex Prompt Example
Combine multiple Liquid features:Learn More
See Liquid Templating for complete syntax guide including:- All available filters (string, number, array)
- Control flow (if/elsif/else, for loops, unless, case/when)
- Variables and assignments
- Common patterns and examples
- Input/output samples for all syntax
Error Handling
Define what happens if the LLM block fails. Options:- Terminate workflow: Stop execution immediately
- Continue execution: Proceed to next step despite error
- Retry: Run the block again until it succeeds, up to the Number of retries you choose (1–5). If every retry fails, the workflow stops at this block.
Best Practices
- Use specific, clear prompts for better results
- Reference previous step outputs using
{{step_n.output}}syntax - Use system instructions to maintain consistent tone across runs
- Test with different models to find the best balance of quality and speed
- Enable web search for queries requiring current information or recent events
- Use allowed domains to limit sources to trusted, authoritative sites
- Choose “Separate answer and citations” format when processing citations in LLM blocks
- Note that web search adds latency and increases credit usage per request
Common Use Cases
What’s Next
Now that you understand the LLM block:- Get AI-generated search summaries with Google AI Overview
- See how to connect blocks in Building Workflows
- Use placeholders in Placeholder Referencing