A durable journal underneath your ADK agent

Crash-survival, exactly-once-effective tool calls, and an explicit UNKNOWN outcome — without changing one line of your ADK agent code.

10-minute quickstart Concepts The treatise GitHub

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Wire it in fifteen lines

Python Go TypeScript Java

import tape
from tape.adk import durable_app

app, runner = durable_app(
    name="treasury",
    agent=root_agent,                                # your ADK LlmAgent
    budget=tape.Budget(usd_cap=50, token_cap=2_000_000),
)

import (
    "context"
    tape "github.com/vamsiramakrishnan/durable-agents/tape/sdk/go"
)

d, _ := tape.NewDurableApp(ctx, tape.DurableConfig{
    Name:   "treasury",
    Budget: tape.Budget{USDCap: 50, TokenCap: 2_000_000},
})
defer d.Close()

import { durableApp } from 'tape-ts';

const app = durableApp({
  name: 'treasury',
  budget: { usdCap: 50, tokenCap: 2_000_000 },
});

import dev.tape.DurableApp;

try (DurableApp app = DurableApp.wire(new DurableApp.Config()
        .name("treasury")
        .budget(new DurableApp.Budget(50.0, 2_000_000)))) {
    // app.client() is the journalled gRPC client
}

Tool bodies stay plain. Mark a tool with @tape.outbox_tool(...) and the outbox reactor owns the dispatch — non-idempotent upstreams stop being a footgun. → ADK on Tape

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What you get

• Crash-survival

  ---

  Every decision and effect is journaled. A crashed run reconstructs and continues. Confirmed effects are not re-executed — once is the contract.

  Replay & resume

• Non-idempotent safety

  ---

  Outbox + reconciliation makes UNKNOWN a first-class outcome. Blind retry on a wire transfer is structurally impossible.

  Non-idempotent upstreams

• Production on GCP

  ---

  Cloud Run · GKE Autopilot · AlloyDB · Bigtable · Spanner · Pub/Sub · Secret Manager · OTel. One Typer CLI composes the whole topology.

  Deploy on Cloud Run

• Four SDKs, one wire

  ---

  Python, Go, TypeScript, Java — identical surface, language-idiomatic shape. The CLI stays Python; your agent process can be any of the four.

  SDK reference

• Sharp primitives

  ---

  Reactive KV with watch streams. Durable gates. Budgets as run state. Compensation registries. A reactor event bus.

  Concepts

• Visible IaC

  ---

  Terraform/OpenTofu modules + a Helm chart you can read, edit, and own. No black-box managed runtime — the substrate is yours.

  Cloud Run topology

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Choose your entry point

• I want to build an agent

  ---

  Start with the quickstart. Ten minutes to a recovering, observable agent on your laptop. Then read the ADK-on-Tape recipe.

  1. Install
  2. Quickstart
  3. ADK on Tape
  4. First crash-survival

• I want to learn the model

  ---

  The Concepts section is the mental model: journal, effects, reactors, UNKNOWN, compensation, replay. Read these before you scale.

  1. Why Tape exists
  2. The journal
  3. Effects & idempotency
  4. UNKNOWN — the third outcome

• I'm going to operate this

  ---

  Stores, reactors, observability, tenancy. Then the deployment topology and the IAM cheat sheet.

  1. Storage backends
  2. Observability
  3. Cloud Run deployment
  4. IAM cheat sheet

• I want the argument

  ---

  The treatise is the why. It's long; it earns the read. The spec turns the argument into a system; the parity matrix names the trade-offs.

  1. Treatise
  2. Tape spec
  3. Event bus
  4. Parity matrix

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Three commands to production

pip install -e tape/sdk/python    # tape-py — SDK + ADK adapter
pip install -e tape/cli           # tape   — the standalone CLI

tape init treasury                # scaffold a new project
cd treasury && tape dev           # server + reactors + agent on sqlite

tape provision gcp --apply        # render & apply Terraform on GCP
tape deploy gcp --target cloud-run

→ Quickstart walks through each command with what to expect.

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Honest project status

Surface	Status
Python SDK + ADK adapter	Reference implementation
Go / TypeScript / Java SDKs	Wired client + smoke tests
Rust server	SQLite / Postgres / AlloyDB
Bigtable backend	Production-ready
Spanner backend	Experimental — gated
Hard multi-tenancy	Design-only — proto change pending
Continue-as-new, child workflows	Roadmap

The roadmap and trade-offs are explicit on the parity matrix. When something doesn't exist yet, the docs say so.

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Get started in 10 minutes Help & FAQ