Gemini Interactions API Skill

This skill provides instructions for authenticating, connecting to, and utilizing the stateful, server-managed Gemini Interactions API on Gemini Enterprise Agent Platform.

The Interactions API is the modern, recommended way to execute Generative AI agent conversations, background research tasks, multi-turn chats, and structured, multi-step workflows.

[!IMPORTANT] CRITICAL: Unified SDK, Latest Models & GEAP Targeting * Unified SDK: Use the Google Gen AI SDK (google-genai >= 2.3.0 for Python, @google/genai >= 2.3.0 for JS/TS). SDK versions >= 2.0.0 are the minimum floor at which the steps schema activates, but >= 2.3.0 is the supported/recommended floor. Legacy SDKs like google-cloud-aiplatform, @google-cloud/vertexai, and google-generativeai are strictly unsupported for Interactions. * Mandatory Instruction: When explaining client initialization or writing import code, you must explicitly state/warn the user that legacy packages like google-cloud-aiplatform or google-generativeai are strictly unsupported for interactions. * Latest Models Only: Use gemini-3.5-flash (fast, balanced, multimodal — the recommended default), gemini-3.1-pro-preview (complex reasoning, coding, research), or gemini-3.1-flash-lite (cost-efficient, high-frequency lightweight tasks). Refer to the latest model versions to check for new updates. Legacy models (gemini-3-flash-preview, gemini-2.5-*, gemini-2.0-*, gemini-1.5-*) are deprecated and do not support interactions. * Mandatory Instruction: In any interaction response, you must warn the user that legacy models like gemini-2.5-*, gemini-2.0-*, or gemini-1.5-* are deprecated and unsupported for the Interactions API. * GEAP requires a provisioned agent (no direct base-model calls yet): On Gemini Enterprise Agent Platform (GEAP), direct/base-model calls (model="...") via the Interactions API are not supported yet. You must target a provisioned agent or endpoint with the agent="<AGENT_ID>" parameter instead of model="...". The code examples in this skill use agent=... for this reason. (This is the primary difference from the ai.google.dev documentation for Interactions, which uses model=... — while model=... is valid for other Gemini API contexts, it is not supported on the Agent Platform.) Provision an agent per the Agent Platform docs and pass its ID as agent. * Turn-Scoped Parameters: Parameters like tools, system_instruction, and generation_config are turn-scoped. They MUST be passed with each interaction request.

1. Authentication

Before running any code, ensure you are authenticated with Application Default Credentials (ADC) and have the necessary API enabled.

1. Login:

   gcloud auth application-default login
   

2. Enable API (if not already enabled):

   gcloud services enable aiplatform.googleapis.com
   

2. Client Initialization

You can initialize the client using environment variables (recommended) or by passing explicit configuration parameters.

Option A: Environment Variables (Recommended)

Configure environment variables to let the SDK automatically resolve settings:

export GOOGLE_GENAI_USE_ENTERPRISE=true
export GOOGLE_CLOUD_PROJECT="your-project-id"
export GOOGLE_CLOUD_LOCATION="global"

Python

from google import genai

# The SDK automatically picks up the environment variables
client = genai.Client()

TypeScript/JavaScript

import { GoogleGenAI } from "@google/genai";

// The SDK automatically picks up the environment variables
const ai = new GoogleGenAI();

Option B: Explicit Inline Parameters

Alternatively, pass configuration values directly inside your code:

Python

from google import genai
import google.auth

_, project_id = google.auth.default()
client = genai.Client(enterprise=True, project=project_id, location="global")

TypeScript/JavaScript

import { GoogleGenAI } from "@google/genai";

const ai = new GoogleGenAI({
    enterprise: {
        project: "your-project-id",
        location: "global"
    }
});

3. Core Interactions API Usage

Quick Start (Single-Turn)

Submit a single prompt and read the final text response. Under the modern schema, output content is retrieved from the steps list.

Python

interaction = client.interactions.create(
    agent="your-agent-id",  # GEAP: target a provisioned agent, not a base model
    input="Explain serverless computing in one sentence."
)
# Use the output_text convenience accessor (combined text from the trailing model_output steps)
print(interaction.output_text)

TypeScript/JavaScript

const interaction = await ai.interactions.create({
    agent: "your-agent-id", // GEAP: target a provisioned agent, not a base model
    input: "Explain serverless computing in one sentence."
});
console.log(interaction.output_text);

Stateful Conversation (Multi-Turn)

Interactions are stateful by default. Store the conversation state in the cloud and reference it in the subsequent turn using previous_interaction_id.

Python

# Turn 1: Introduce ourselves
# Interactions are stored by default (store=True); pass store=False to disable
# server-side retention (which also disables previous_interaction_id and background).
turn1 = client.interactions.create(
    agent="your-agent-id",
    input="Hi! My name is John. I am working on AI agents.",
    store=True
)
print(f"Turn 1: {turn1.output_text}")

# Turn 2: Refer back to the stored turn state
turn2 = client.interactions.create(
    agent="your-agent-id",
    input="What is my name?",
    previous_interaction_id=turn1.id
)
print(f"Turn 2: {turn2.output_text}")

TypeScript/JavaScript

// Turn 1 (interactions are stored by default; pass store: false to disable)
const turn1 = await ai.interactions.create({
    agent: "your-agent-id",
    input: "Hi! My name is John. I am working on AI agents.",
    store: true
});

// Turn 2
const turn2 = await ai.interactions.create({
    agent: "your-agent-id",
    input: "What is my name?",
    previousInteractionId: turn1.id
});
console.log(turn2.output_text);

Real-Time Streaming

Stream responses in real-time. Passing stream=True returns an iterable chunk generator.

Python

# The stream yields typed events, not full interaction snapshots. The sequence is:
# interaction.created -> (step.start -> step.delta(s) -> step.stop)+ -> interaction.completed
for event in client.interactions.create(
    agent="your-agent-id",
    input="Write a short poem about debugging.",
    stream=True
):
    if event.event_type == "step.delta":
        if event.delta.type == "text":
            print(event.delta.text, end="", flush=True)
    elif event.event_type == "interaction.completed":
        print()

TypeScript/JavaScript

// The stream yields typed events, not full interaction snapshots. The sequence is:
// interaction.created -> (step.start -> step.delta(s) -> step.stop)+ -> interaction.completed
const responseStream = await ai.interactions.create({
    agent: "your-agent-id",
    input: "Write a short poem about debugging.",
    stream: true
});

for await (const event of responseStream) {
    if (event.event_type === "step.delta") {
        if (event.delta.type === "text") {
            process.stdout.write(event.delta.text);
        }
    } else if (event.event_type === "interaction.completed") {
        console.log();
    }
}

Structured Output (Pydantic / Polymorphic response_format)

Retrieve structured, type-safe JSON matching a schema. Under the modern Interactions API, a polymorphic response_format argument directly takes the target schema structure.

Python

from pydantic import BaseModel, Field

class Book(BaseModel):
    title: str = Field(description="The title of the book")
    author: str = Field(description="The book's author")
    year_published: int

interaction = client.interactions.create(
    agent="your-agent-id",
    input="Recommend one famous sci-fi book.",
    response_format=Book
)

# The text will be a valid JSON matching the Book schema
print(interaction.output_text)

TypeScript/JavaScript

import { Type } from "@google/genai";

const BookSchema = {
    type: Type.OBJECT,
    properties: {
        title: { type: Type.STRING, description: "The title of the book" },
        author: { type: Type.STRING, description: "The book's author" },
        yearPublished: { type: Type.INTEGER }
    },
    required: ["title", "author", "yearPublished"]
};

const interaction = await ai.interactions.create({
    agent: "your-agent-id",
    input: "Recommend one famous sci-fi book.",
    responseFormat: BookSchema
});

console.log(interaction.output_text);

Function Calling (Agent Tool Use)

Define local tools (functions) and submit execution results to the stateful interaction history.

Python

import json

def get_stock_price(ticker: str) -> float:
    """Gets the stock price for a given ticker symbol."""
    if ticker.upper() == "GOOG":
        return 175.50
    return 100.0

# Turn 1: Pass tools to the model
interaction = client.interactions.create(
    agent="your-agent-id",
    input="What is the stock price of GOOG?",
    tools=[get_stock_price]
)

# In the flat steps schema, a tool request is a top-level step of type
# "function_call" with flat `name` and `arguments` fields (no nested tool_calls).
for step in interaction.steps:
    if step.type == "function_call" and step.name == "get_stock_price":
        ticker_arg = step.arguments.get("ticker")
        price = get_stock_price(ticker_arg)

        # Turn 2: Submit the result back as a function_result step. Reference the
        # originating call via call_id=step.id, and pass tools again (turn-scoped).
        final_turn = client.interactions.create(
            agent="your-agent-id",
            input=[
                {
                    "type": "function_result",
                    "name": step.name,
                    "call_id": step.id,
                    "result": [{"type": "text", "text": json.dumps(price)}],
                }
            ],
            tools=[get_stock_price],
            previous_interaction_id=interaction.id
        )
        print(final_turn.output_text)

TypeScript/JavaScript

import { Type } from "@google/genai";

// Define local tool
function getStockPrice({ ticker }: { ticker: string }): number {
    if (ticker.toUpperCase() === "GOOG") {
        return 175.50;
    }
    return 100.00;
}

// Turn 1: Pass tools to the model
const toolDeclaration = {
    functionDeclarations: [{
        name: "getStockPrice",
        description: "Gets the stock price for a given ticker symbol.",
        parameters: {
            type: Type.OBJECT,
            properties: {
                ticker: { type: Type.STRING, description: "The stock ticker symbol" }
            },
            required: ["ticker"]
        }
    }]
};

const interaction = await ai.interactions.create({
    agent: "your-agent-id",
    input: "What is the stock price of GOOG?",
    tools: [toolDeclaration]
});

// In the flat steps schema, a tool request is a top-level step of type
// "function_call" with flat `name` and `arguments` fields (no nested toolCalls).
const fcStep = interaction.steps.find(s => s.type === "function_call");
if (fcStep && fcStep.name === "getStockPrice") {
    const tickerArg = fcStep.arguments.ticker as string;
    const price = getStockPrice({ ticker: tickerArg });

    // Turn 2: Submit the result back as a function_result step. Reference the
    // originating call via call_id=fcStep.id, and pass tools again (turn-scoped).
    const finalTurn = await ai.interactions.create({
        agent: "your-agent-id",
        input: [{
            type: "function_result",
            name: fcStep.name,
            call_id: fcStep.id,
            result: [{ type: "text", text: JSON.stringify(price) }]
        }],
        tools: [toolDeclaration],
        previousInteractionId: interaction.id
    });
    console.log(finalTurn.output_text);
}

4. Accessing the Interactions API via REST

For shell-based scripts, debugging, or non-Python/JS environments, you can communicate with the stateful Interactions API directly using raw HTTP/REST requests via curl.

1. REST Endpoint

The REST API endpoint for interactions is:

POST https://aiplatform.googleapis.com/v1beta1/projects/{PROJECT_ID}/locations/{LOCATION}/interactions

• LOCATION: Use global (or custom region if required).
• PROJECT_ID: Your Google Cloud Project ID.

2. Set up Variables & Authentication Header

Set your target agent ID (e.g., model or custom agent path) and access token generated from Application Default Credentials:

AGENT_ID="your-agent-id"
ACCESS_TOKEN=$(gcloud auth print-access-token)

3. Single-Turn Interaction Payload

Send a request to start an interaction using the agent variable:

curl -X POST "https://aiplatform.googleapis.com/v1beta1/projects/${PROJECT_ID}/locations/global/interactions" \
  -H "Authorization: Bearer ${ACCESS_TOKEN}" \
  -H "Content-Type: application/json" \
  -d '{
    "agent": "'"${AGENT_ID}"'",
    "input": [{
      "type": "user_input",
      "content": [{
        "type": "text",
        "text": "Explain serverless computing in one sentence."
      }]
    }]
  }'

Response Example

A synchronous POST request returns a JSON object containing the conversation step details and unique identifiers:

{
  "id": "your-interaction-id",
  "status": "completed",
  "steps": [
    {
      "type": "model_output",
      "content": [
        {
          "type": "text",
          "text": "Serverless computing is a cloud execution model where the cloud provider dynamically manages the allocation and provisioning of servers, charging customers based on actual usage rather than pre-purchased capacity."
        }
      ]
    }
  ],
  "usage": {
    "total_tokens": 24751,
    "total_input_tokens": 23894,
    "total_output_tokens": 857
  },
  "created": "2026-05-08T10:44:43Z",
  "updated": "2026-05-08T10:44:43Z",
  "environment_id": "your-environment-id",
  "object": "interaction"
}

4. Multi-Turn Stateful Interaction Payload

To continue an existing conversation statefully, specify the previous_interaction_id in the JSON payload:

curl -X POST "https://aiplatform.googleapis.com/v1beta1/projects/${PROJECT_ID}/locations/global/interactions" \
  -H "Authorization: Bearer ${ACCESS_TOKEN}" \
  -H "Content-Type: application/json" \
  -d '{
    "agent": "'"${AGENT_ID}"'",
    "store": true,
    "previous_interaction_id": "YOUR_PREVIOUS_INTERACTION_ID",
    "input": [{
      "type": "user_input",
      "content": [{
        "type": "text",
        "text": "Can you elaborate on that?"
      }]
    }]
  }'

5. Streaming Output Payload

To stream updates in real time (Server-Sent Events format), pass "stream": true in the payload:

curl -X POST "https://aiplatform.googleapis.com/v1beta1/projects/${PROJECT_ID}/locations/global/interactions" \
  -H "Authorization: Bearer ${ACCESS_TOKEN}" \
  -H "Content-Type: application/json" \
  -d '{
    "agent": "'"${AGENT_ID}"'",
    "stream": true,
    "input": [{
      "type": "user_input",
      "content": [{
        "type": "text",
        "text": "Write a long story about space travel."
      }]
    }]
  }'

The endpoint will return a chunked stream where each event begins with data: containing JSON updates with the event_type and step contents.

How curl handles streaming: By default, when "stream": true is passed, the server responds with Transfer-Encoding: chunked and Content-Type: text/event-stream (Server-Sent Events). curl will automatically keep the connection open and print the incoming data chunks to stdout in real time as they are pushed by the server. The user does not need to poll or pull further; the complete sequence of events streams continuously until completion.

5. Data Model & Step Types Reference

An Interaction response contains steps, an array of typed step objects representing a structured timeline of the interaction turn. Read the current step type rather than assuming the last step is text — the trailing step may be a function_call or a thought.

Step Types

User steps:

• user_input: User input (text, audio, multimodal). Contains a content array. (This is why REST input payloads use "type": "user_input", not "role": "user".)

Model/server steps:

• model_output: Final model generation. Contains a content array with text, image, audio, etc. (REST responses use "type": "model_output", not "role": "model".)
• thought: Model reasoning / chain of thought. Has a signature field and optional summary.
• function_call: Tool call request, with flat id, name, and arguments fields (there is no nested tool_calls list).
• function_result: Tool result you send back, with call_id, name, and result fields.
• google_search_call / google_search_result, code_execution_call / code_execution_result, url_context_call / url_context_result, mcp_server_tool_call / mcp_server_tool_result, file_search_call / file_search_result: built-in and remote tool steps.

Content types (inside the content array on model_output and user_input steps)

• text: Text content (text field).
• image / audio / document / video: Content with data, mime_type, or uri.

Convenience accessor

• output_text: The combined text from the trailing model_output steps. Prefer this over hand-walking steps[-1].content[0].text, which breaks when the last step is a tool call or a thought.

Streaming Event Types

Storage & retention

Interactions are stored by default (store=True), which enables stateful features like previous_interaction_id and background execution. Passing store=False disables server-side retention and therefore also disables previous_interaction_id and background — in that mode you must pass the full conversation history in input on each turn.