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Moira Documentation

Magic Variables

Overview

Magic variables are special input fields that trigger automatic behavior beyond normal context storage.

execution_note

Updates the execution’s note field for tracking purposes.

Usage

{
  "inputSchema": {
    "type": "object",
    "properties": {
      "execution_note": {
        "type": "string",
        "description": "Note to identify this execution"
      }
    }
  }
}

Behavior

When agent provides execution_note:

  1. Value stored in context like normal
  2. Execution record’s note field updated in database
  3. Note visible in execution lists and session queries

Use Cases

Track what’s being worked on:

{
  "directive": "Document what you're working on for tracking.",
  "inputSchema": {
    "properties": {
      "execution_note": {
        "type": "string",
        "description": "Feature/task being developed"
      }
    },
    "required": ["execution_note"]
  }
}

Update note on task changes:

{
  "directive": "Task requirements changed. Update the execution note.",
  "inputSchema": {
    "properties": {
      "execution_note": { "type": "string" }
    }
  }
}

execution_note passes through inputSchema validation. Include in required array to enforce agents provide execution identification.

Querying Notes

Notes appear in session queries:

mcp__moira__session({ action: "executions" });
// Returns executions with note field populated

System Variables

These variables are automatically available in context:

executionId

Current process execution ID.

{{executionId}}

workflowId

Current workflow identifier.

{{workflowId}}

Usage Example

{
  "directive": "Process ID: {{executionId}}\nWorkflow: {{workflowId}}\n\nDocument this for reference."
}

Expression Variables

Variables modified by expression nodes:

Counter Variables

Declared as globals in variableRegistry with a default:

{
  "variableRegistry": {
    "current_step_index": { "type": "number", "description": "Current step index", "default": 1 },
    "current_iteration": { "type": "number", "description": "Current iteration", "default": 1 }
  }
}

Modified by expression (expression nodes assign to globals by bare name):

{
  "type": "expression",
  "expressions": ["current_step_index = current_step_index + 1", "current_iteration = 1"]
}

Declare counter variables in variableRegistry with a default so they exist before expression nodes access them.

Template Processing

All magic and context variables work with templates:

Simple Access

{{variable_name}}

Nested Access

{{user.profile.name}}

Array Access

{{items[0]}}
{{items[0].field}}

Conditional Templates

{{#if execution_note}}Note: {{execution_note}}{{/if}}

See Also