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Persistent memory for Google ADK agents, on your own machine

25 October 2026 · Semurg · 5 min read · Markdown

Last checked on r11.132.20261027.a274a28 (27 Oct 2026): every command below ran on a fresh node of that release. The current release is r11.135.20261028.2ff2348 (28 Oct 2026), and the commands have not been re-checked on it yet (how)

google-adkpythonmcpagentsmemoryhow-to

Tested end to end with google-adk 2.13.0 and mcp 1.30.0. The release it ran on is named in the checked line at the top of this page.

An agent built with Google's Agent Development Kit (ADK) forgets what it learned when its session ends. This guide gives it a memory that outlives the session: a Semurg node on your own machine, reached through ADK's own McpToolset, where every fact stays on your disk and comes back cited to where it was said. Any other agent or framework that uses the same node and the same scope reads the same memory.

Your ADK program stores a fact through ADK's MCP toolset; your node keeps it in the scope you named, on your own disk; a later run, another agent or a plain HTTP call on the same scope reads it back, cited.Your ADK programADK's McpToolsetYour scope, on yournodeA later run, anotheragent, or plain HTTPtoken and scoperememberthe same fact, cited

What you need

  • An Intel or AMD x86_64 machine with Ubuntu 24.04, on Linux directly or on Windows through WSL2. One node is free, with no licence key.
  • Python 3.12, which Ubuntu 24.04 ships. We test in the official python:3.12-slim container.

Step one: install a node

On Ubuntu 24.04 (x86_64), with sudo:

bash
curl -fsSL https://one.semurg.io/install | sudo bash

The install page lists what the installer needs and what it changes. The installer ends by printing your API token, and the node keeps a copy. Put it in a file only you can read, and have every new terminal load it:

bash
mkdir -p ~/.config/semurg
(umask 077; sudo grep '^SEMURG_API_TOKEN=' /etc/semurg/semurg.env | cut -d= -f2- > ~/.config/semurg/token)
echo 'export SEMURG_API_TOKEN="$(cat ~/.config/semurg/token)"' >> ~/.bashrc
export SEMURG_API_TOKEN="$(cat ~/.config/semurg/token)"

Step two: install ADK

Ubuntu keeps its own Python packages apart, so install into a virtual environment of your own. The install line keeps the mcp package below its next major version, as in the setup we test; keep the quotes, so the shell does not read < as a redirect.

bash
sudo apt install -y python3-venv
python3 -m venv ~/semurg-adk && . ~/semurg-adk/bin/activate
pip install google-adk 'mcp<2'

Step three: connect

Save the program below as snippet.py. It is the program our tests run as written, shown here from the agents page rather than copied, so what you read is always the file that ran.

Python: Google ADK
# Run: python snippet.py   (SEMURG_API_TOKEN must be set in the environment)
import asyncio, os
from google.adk.tools.mcp_tool.mcp_toolset import McpToolset, StreamableHTTPConnectionParams

URL = os.environ.get("SEMURG_MCP_URL", "http://127.0.0.1:4000/v1/mcp")
HEADERS = {"Authorization": "Bearer " + os.environ["SEMURG_API_TOKEN"],
           "X-Semurg-Scope": os.environ.get("SEMURG_MCP_SCOPE", "default")}
FACTS = {"entities": [{"name": "Ada", "type": "person"}, {"name": "Acme", "type": "organisation"}],
         "relations": [{"source": "Ada", "target": "Acme", "type": "WORKS_AT"}]}


async def main():
    toolset = McpToolset(connection_params=StreamableHTTPConnectionParams(url=URL, headers=HEADERS))
    try:
        by = {t.name: t for t in await toolset.get_tools()}
        await by["memory_remember"].run_async(args={"facts": FACTS}, tool_context=None)
        print(await by["memory_recall"].run_async(args={"subject": "Ada"}, tool_context=None))
    finally:
        await toolset.close()


asyncio.run(main())

Ran: this exact file, end to end against a fresh node on release r11.132.20261027.a274a28 in python:3.12-slim, with google-adk 2.13.0, mcp 1.30.0. Install: pip install google-adk 'mcp<2'. Its run record and every other framework: /agents.

It reads your token from SEMURG_API_TOKEN, the node's address from SEMURG_MCP_URL (without it, http://127.0.0.1:4000/v1/mcp) and the scope from SEMURG_MCP_SCOPE (without it, the scope named default). It builds an McpToolset with StreamableHTTPConnectionParams carrying the token and the X-Semurg-Scope header, stores two facts with memory_remember (Ada works at Acme), prints what memory_recall returns for Ada and closes the toolset.

Step four: run it

Give the program a scope of its own, so it never writes into a memory you use for real work:

bash
export SEMURG_MCP_SCOPE=try-google-adk
python snippet.py

It prints the tool result ADK hands back, which carries the node's answer for Ada: state set to answered and the WORKS_AT fact that links Ada to Acme, each item cited. Storing the same facts again changes nothing, so it is safe to run twice.

Now read the same fact from outside ADK, over plain HTTP. What one client writes, any other client on the same node and scope reads:

bash
curl -sS http://127.0.0.1:4000/v1/memory/recall \
  -H "Authorization: Bearer $SEMURG_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"scope":"try-google-adk","subject":"Ada"}'

The memory tools in ADK

toolset.get_tools() returns each memory tool as an ADK tool with the same name; the program runs them with run_async. To let an agent choose, put the same McpToolset in the agent's tools (our test runs the tools directly, without a model).

  • memory_status: reports whether shared memory is on for this node and which of your scopes hold facts.
  • memory_remember: stores entities, the relationships between them and the passages they came from, or plain text, with an optional source label and date.
  • memory_recall: recalls what is stored about one named entity, its own facts first, each item cited.
  • memory_relate: adds one typed relationship between two entities in a scope, creating an end that is not stored yet.
  • memory_context: answers a question in plain words with cited items and a verdict on whether the store covers it.
  • memory_document: takes a whole document (PDF with a text layer, Word, HTML or plain text) and stores it as cited passages in a scope.
  • memory_forget: deletes one thing per call: an entity and everything that names it, one fact, one document, every document under a source label, or the whole scope. It is unreachable at once and not yet wiped from the disk.
  • memory_export: reads everything a scope holds, one page per call: send each reply's next back as cursor until it is empty. The records are the entities, the facts with their dated sources and whether each is current or ended, and each stored document once; a forgotten passage is never exported.
  • memory_import: stores the records memory_export produced into any scope, through the same writes memory_remember makes. A page sent twice stores nothing twice, and the reply names every record it skipped.

Every answer says its state: answered, nothing_stored (nothing stored matched, so the agent should say it does not know) or could_not_judge.

Troubleshooting

  • KeyError: 'SEMURG_API_TOKEN': the token is not in this shell. Run the last line of step one, or open a new terminal. If pip answers externally-managed-environment, activate the virtual environment from step two.
  • An error that names 401 (unauthorised): the token is wrong or belongs to another node. Read it again from the node as in step one.
  • When the connection to the node is lost, ADK's tool wrapper returned the failure as a result with an error key in our tests, rather than raising. Check a result for error before your code treats it as memory.
  • A warning that Google's default credentials were not found is ADK's own, about Google's services; it is not about your node.
  • After the node restarts (an update restarts it), the first call can fail; in our October 2026 restart test, run on an earlier release, ADK's client then reconnected by itself. For a node that is up but stalled, set the per-call timeout your framework offers.

Use 127.0.0.1 rather than localhost: on Ubuntu localhost can resolve to the IPv6 address first, and the node listens on IPv4 loopback only. To reach a node on another machine, set SEMURG_MCP_URL, or forward its port with ssh -N -L 4000:127.0.0.1:4000 you@your-node.

Next

This post was written with AI assistance. Every result in it is checked against a published release or record before the post goes out.

How these commands were checked

Our test farm ran each program shown from /agents, the very file our test farm ran end to end, against a fresh node of the published release r11.132.20261027.a274a28. A post is published only when every one of them passed there.

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