Data channels overview

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Micro-composability: making the agent native to your application

• Agent Session Parameters establish identity and authorization at session creation.
• Situational Awareness feeds the agent live page context so it knows what the user is looking at.
• Page Tools let the agent call JavaScript functions on the host page, turning conversation into action.
• Pass-through Parameters inject data directly into tool calls without the LLM wasting tokens copying it.
• sendMessage lets the host page trigger the agent programmatically, without the user typing a word. Each of these is a single JavaScript call; each works independently and each becomes more powerful when combined with the others.

TL;DR: there are four data channels and one programmatic trigger for connecting a host page to a Mindset AI agent. Each has a different direction, destination, and purpose. Together they let you make the agent native to your application without backend work or platform-side configuration.

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Per-channel guides

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The four channels

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1. Agent Session Parameters

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What they are

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What gets sent

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Where it goes

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What it is not

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Security boundary

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2. Situational Awareness

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What it is

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How to set it

<mindset-agent
  agent-uid="your-agent-uid"
  situational-awareness='{
    "page": "Employee Performance Dashboard",
    "active_tab": "Quarterly Reviews",
    "user_role": "Finance Manager"
  }'
></mindset-agent>

const agent = document.querySelector('mindset-agent');
agent.setSituationalAwareness({
  page: 'Employee Performance Dashboard',
  active_tab: 'Quarterly Reviews',
  user_role: 'Finance Manager',
});

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Where it goes

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Design properties

• Transient per message. Read fresh from the store on each message send. Not persisted in conversation history. No stale context accumulation.
• Size-aware. 10,000 character default limit. For dedicated agents where the SA context is the primary input (for example, processing a transcript or document), opt into the 20,000 character ceiling via extendedSituationalAwareness: true in mindset.init(). The LLM reads the entire SA payload on every message, so larger payloads increase token cost.
• Generic pass-through. The platform does not interpret keys. The meaning is a contract between the host page and the agent.

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3. Pass-through Parameters

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The problem they solve

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How to set them

<mindset-agent
  agent-uid="your-agent-uid"
  passthrough-params='{
    "update_employee.employee_id": "EMP-4821",
    "submit_report.report_body": "<full report content>"
  }'
></mindset-agent>

const agent = document.querySelector('mindset-agent');
agent.setPassthroughParams({
  'update_employee.employee_id': 'EMP-4821',
  'submit_report.report_body': reportContent,
});

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How it works

1. Strips the parameter from the tool definition. Before presenting tools to the agent, any parameter that has a pass-through value is removed from the tool’s schema. The agent sees a simplified version of the tool where this parameter does not exist.
2. Re-injects the parameter before execution. When the agent calls the tool, the platform adds the pass-through value back into the tool call before dispatching it. The tool receives the complete call as if the agent had generated all parameters.

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Design properties

• Transient per message. Same lifecycle as Situational Awareness.
• Agent never sees it. The values are not added to the system prompt, conversation history, or any part of the agent’s context.
• Deterministic. The value that reaches the tool is exactly what the host page sent, byte for byte.
• Higher size ceiling. The data never enters the agent’s context window, so the constraint is transport and tool-side, not token budget.
• Works on both MCP tools and page tools. Same mechanic for both. The SDK strips the parameter from the schema the agent sees, then injects the value when the tool is invoked.

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Complementary to Situational Awareness

• Situational Awareness sends page: "Employee Profile" and employeeName: "Sarah Chen" so the agent knows what the user is looking at and can respond conversationally.
• Pass-through Parameters sends the full employee profile JSON that the update tool needs, so the agent doesn’t have to copy it.

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4. Page Tools

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What they are

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How to register them

const agent = document.querySelector('mindset-agent');

agent.setPageTools([{
  name: 'add_to_cart',
  description: 'Add the product the user is currently viewing to the shopping cart.',
  runningDescription: 'Adding to cart...',
  completedDescription: 'Added to cart',
  parameters: {
    type: 'object',
    properties: {
      quantity: { type: 'number', description: 'Number to add (default 1)' },
    },
  },
  handler: async (args) => {
    await myApp.cart.addItem(currentProductId, args.quantity ?? 1);
    const cart = await myApp.cart.getState();
    return { success: true, cartTotal: cart.formattedTotal };
  },
}]);

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How it works

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Design properties

• You control the capabilities. The agent can only call tools you have registered. No registration, no capability. Different pages can offer different tools. Admin users can get tools that regular users don’t.
• Local execution. Handlers run in the browser, in the user’s authenticated session. They have access to your DOM, your client-side state, your APIs. If your frontend can do it, a Page Tool can do it.
• Dynamically updatable. Call setPageTools() as the application state changes. The agent’s available actions evolve with the page.
• Complementary to MCP servers. MCP servers connect the agent to backend services behind your infrastructure. Page Tools connect the agent to the application in front of your user.

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Programmatic trigger: sendMessage

const agent = document.querySelector('mindset-agent');

// Visible: appears in the chat UI like a user-typed message
agent.sendMessage('Analyse the transcript and populate the form.');

// Silent: agent responds, but the trigger is hidden from the chat UI
agent.sendMessage('Check for pending tasks.', { silent: true });

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How the four channels relate

Host Page
  │
  ├── Session Creation ──→ Agent Session Parameters
  │                            │
  │                            ├── x-user-id, x-session-tags ──→ MCP Server Headers
  │                            └── contextUids, mcpserverUids ──→ Agent Capability Scope
  │
  ├── Per Message ──→ Situational Awareness
  │                       └──→ Agent's System Prompt
  │
  ├── Per Message ──→ Pass-through Parameters
  │                       │
  │                       ├── Strip from tool schema ──→ Agent sees simplified tool
  │                       └── Re-inject before dispatch ──→ Tool receives complete call
  │
  └── Per Message ──→ Page Tools
                          └──→ Agent calls handler ──→ Handler runs in browser ──→ Result back to agent

• The agent never sees Agent Session Parameters or Pass-through Parameter values.
• MCP servers never receive Situational Awareness or Page Tool calls.
• Agent Session Parameters never enter the agent’s context.
• Pass-through Parameters never appear in conversation history.
• Page Tools execute locally, never on the server.

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