PromptL Syntax Guide

Comprehensive guide for writing PromptL prompts in the Latitude platform. PromptL is a versatile, human-readable language that simplifies defining and managing dynamic prompts for LLMs.

When to Apply

Reference these guidelines when:

Writing new PromptL prompts for Latitude
Configuring LLM models and parameters
Using variables, conditionals, or loops in prompts
Creating multi-step chains or agentic workflows
Defining tools for function calling
Referencing other prompts (snippets)
Working with structured JSON output schemas

Syntax Categories

| Category | Purpose | Key Syntax | |----------|---------|------------| | Configuration | Define model, provider, and parameters | --- YAML block | | Messages | Structure conversations | <system>, <user>, <assistant>, <tool> | | Variables | Dynamic content | {{ variable }} | | Conditionals | Dynamic flow control | {{ if }}, {{ else }}, {{ endif }} | | Loops | Iterate over lists | {{ for item in list }}, {{ endfor }} | | Chains | Multi-step prompts | <step> | | Tools | Function calling | tools: in config | | Agents | Autonomous workflows | type: agent | | Snippets | Reusable prompts | <prompt path="..." /> | | Content | Multi-modal content | <content-image>, <content-file> |

Quick Reference

Configuration Block

---
provider: OpenAI
model: gpt-4o
temperature: 0.7
top_p: 0.9
maxSteps: 20
---

Message Tags

<system> - System instructions
<user> - User messages
<assistant> - Assistant responses
<tool> - Tool interaction results
<message role="..."> - Generic message tag

Variables

{{ variable_name }}
{{ variable || "default" }}
{{ set myVar = "value" }}

Conditionals

{{ if condition }}
  content
{{ else }}
  alternative
{{ endif }}

Loops

{{ for item, index in items }}
  {{ index }}: {{ item }}
{{ else }}
  No items
{{ endfor }}

Chains (Multi-step)

<step as="result">
  First step content
</step>

<step>
  Use {{ result }} from previous step
</step>

Tools Configuration

tools:
  - tool_name:
      description: What the tool does
      parameters:
        type: object
        properties:
          param_name:
            type: string
            description: Parameter description
        required:
          - param_name

Agents

---
type: agent
provider: OpenAI
model: gpt-4o
tools:
  - latitude/search
agents:
  - agents/sub-agent-path
maxSteps: 40
---

Structured Output

schema:
  type: object
  properties:
    field_name:
      type: string
      description: Field description
  required:
    - field_name

Prompt References (Snippets)

<prompt path="relative/path/to/prompt" />
<prompt path="shared/policies" variable={{ value }} />

Content Types

<content-text>Plain text</content-text>
<content-image>{{ image_url }}</content-image>
<content-file mime="application/pdf">{{ file_data }}</content-file>

How to Use

Read the AGENTS.md file for the complete detailed guide with all syntax explanations, examples, and best practices.

Each section contains:

Detailed explanation of the feature
Correct usage examples
Common mistakes to avoid
Best practices and tips