Google ADK

Persistent long-term memory for Google ADK agents via Hindsight. The hindsight-google-adk package gives you two complementary patterns:

• HindsightMemoryService — Implements ADK's BaseMemoryService. Pass it to Runner(memory_service=...) and sessions are automatically retained when they end; agents calling search_memory get matching results back from Hindsight.
• create_hindsight_tools(...) — Returns a list of ADK FunctionTools (hindsight_retain, hindsight_recall, hindsight_reflect) the model can call directly inside a turn.

Recommended: Hindsight Cloud

Sign up free for a Hindsight Cloud API key. The integration points at production by default — no local server to manage.

Installation

pip install hindsight-google-adk

Automatic Memory (BaseMemoryService)

import asyncio
from google.adk.agents import LlmAgent
from google.adk.runners import Runner
from google.adk.sessions import InMemorySessionService

from hindsight_google_adk import HindsightMemoryService

memory = HindsightMemoryService.from_url(
    hindsight_api_url="https://api.hindsight.vectorize.io",
    api_key="hsk_...",
)

agent = LlmAgent(name="assistant", model="gemini-2.0-flash")

runner = Runner(
    app_name="my-app",
    agent=agent,
    session_service=InMemorySessionService(),
    memory_service=memory,
)

# ... use runner.run_async(...) as normal. Memory is automatic.

When a session ends, add_session_to_memory retains all of its events to a Hindsight bank derived from (app_name, user_id). When an agent calls search_memory, the integration runs a Hindsight recall against the same bank and returns the results as ADK MemoryEntry objects.

Bank ID derivation

By default, each (app_name, user_id) pair gets its own bank: "{app_name}::{user_id}". Override with bank_id_template:

# Per-user, shared across apps
HindsightMemoryService.from_url(
    hindsight_api_url="https://api.hindsight.vectorize.io",
    api_key="hsk_...",
    bank_id_template="user::{user_id}",
)

# Static bank (shared across all users)
HindsightMemoryService.from_url(
    hindsight_api_url="https://api.hindsight.vectorize.io",
    api_key="hsk_...",
    bank_id_template="my-shared-bank",
)

Explicit Tools (FunctionTool)

Give the agent direct retain / recall / reflect tools when you want it to decide when to call them mid-turn:

from google.adk.agents import LlmAgent
from hindsight_google_adk import create_hindsight_tools

tools = create_hindsight_tools(
    bank_id="user-123",
    hindsight_api_url="https://api.hindsight.vectorize.io",
    api_key="hsk_...",
)

agent = LlmAgent(
    name="assistant",
    model="gemini-2.0-flash",
    tools=tools,
)

The agent gets three tools (toggle with include_retain / include_recall / include_reflect):

• hindsight_retain(content) — store information to long-term memory
• hindsight_recall(query) — search memory and return a numbered list of matches
• hindsight_reflect(query) — synthesize a coherent answer from memory

Global Configuration

For app-wide defaults, call configure(...) once at startup. Subsequent HindsightMemoryService.from_url() / create_hindsight_tools() calls use it as a fallback:

from hindsight_google_adk import configure

configure(
    hindsight_api_url="https://api.hindsight.vectorize.io",
    api_key=None,           # falls back to HINDSIGHT_API_KEY env var
    budget="mid",
    max_tokens=4096,
    bank_id_template="{app_name}::{user_id}",
)

Configuration Reference

Argument	Default	Description
hindsight_api_url	https://api.hindsight.vectorize.io	Hindsight API URL. Cloud by default.
api_key	HINDSIGHT_API_KEY env	Bearer token for Hindsight Cloud.
bank_id_template	"{app_name}::{user_id}"	Format string used to derive the bank id from ADK's app_name / user_id.
budget	"mid"	Recall budget level: low/mid/high.
max_tokens	4096	Max tokens for recall results.
tags	None	Tags added to every retained document. app:<name> and user:<id> are always added.
recall_tags	None	Tags appended to recall queries. user:<id> is always added.
recall_tags_match	"any"	Tag match mode: any / all / any_strict / all_strict.
mission	None	If set, the bank is created (idempotently) on first use with this fact-extraction mission.
context	"google-adk"	Source label attached to retained content.

Production Patterns

Tagging memories per environment

HindsightMemoryService.from_url(
    hindsight_api_url="https://api.hindsight.vectorize.io",
    api_key="hsk_...",
    tags=["env:prod"],
    recall_tags=["env:prod"],
)

app: and user: tags are always added on top of these.

Self-hosted Hindsight

HindsightMemoryService.from_url(
    hindsight_api_url="http://localhost:8888",
)

No api_key needed for unauthenticated local servers.

Combining memory service + tools

You can use both at once — Runner(memory_service=HindsightMemoryService(...)) for automatic retain on session end, and tools=create_hindsight_tools(...) for mid-turn agent-driven recall. They share a bank when the bank ids align.

Requirements

• Python 3.10+
• google-adk>=2.0
• hindsight-client>=0.4.0