bonnie

README

BONNIE

Durable agent runs for Go.
Survive a crash. Wait days for a human. Answer over HTTP.

---

An agent turn normally lives and dies with your process. Kill it mid-tool-call and the work is gone. Ask the user a question and you have to hold the process open until they answer.

BONNIE fixes that. It wraps the Kit agent SDK so a run becomes durable:

run, _ := runner.Start(ctx, "deploy-42", runtime.Input{Text: "Deploy the app."})

if run.State == runtime.RunWaiting {
    fmt.Println(run.Suspend.Prompt) // "Which region?"
    os.Exit(0)                      // ← the process can end here
}

Come back tomorrow, in a different process, and finish it:

run, _ := runner.Resume(ctx, "deploy-42",
    []runtime.InputResponse{{Text: "eu-west-1"}})

fmt.Println(run.Response) // "Deployed to eu-west-1."

The agent remembers the whole conversation, including which tools it already called — so it does not repeat a side effect it has already performed.

Contents

• Install · Quickstart · Park and resume
• Your own tools · Sandboxing · Serve over HTTP
• CLI · Storage · Streaming · Steer and cancel
• How it works · Limits · Docs

Install

As a library:

go get github.com/mark3labs/bonnie

As a CLI:

go install github.com/mark3labs/bonnie/cmd/bonnie@latest

With Nix. This gives you the CLI with the microsandbox CLI (msb) already on its PATH:

nix profile install github:mark3labs/bonnie   # or: nix run github:mark3labs/bonnie

Set a provider key. BONNIE uses whatever Kit is configured for:

export ANTHROPIC_API_KEY=sk-ant-...   # or OPENAI_API_KEY, or GEMINI_API_KEY

Requires Go 1.27+. Sandboxing is optional and needs Docker or msb.

Development shell

The flake also gives you a shell with Go 1.27, golangci-lint, goreleaser, and the microsandbox CLI:

nix develop
go test -race ./...

The repository ships an .envrc, so direnv allow enters the same shell on cd.

Other flake outputs:

Output	What it is
packages.default, packages.bonnie	the BONNIE CLI
packages.microsandbox	the msb CLI plus its libkrunfw
apps.msb	nix run github:mark3labs/bonnie#msb
overlays.default	both packages, for your own nixpkgs

Quickstart

A durable run in 20 lines. The journal on disk is what makes it durable.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/mark3labs/bonnie/runtime"
	kit "github.com/mark3labs/kit/pkg/kit"
)

func main() {
	// Every message is journalled here before it is kept.
	journal, err := runtime.OpenFileJournal(".bonnie")
	if err != nil {
		log.Fatal(err)
	}
	defer journal.Close()

	runner := runtime.NewRunner(journal, runtime.KitAgent(
		kit.WithModel("anthropic/claude-sonnet-4-5"),
	))

	run, err := runner.Start(context.Background(), "run-1",
		runtime.Input{Text: "In one sentence, what is a durable agent run?"})
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(run.Response)
}

Run it again with a different message and the same run ID. BONNIE replays the conversation first, so the agent remembers:

run, _ := runner.Start(ctx, "run-1", runtime.Input{Text: "What did I just ask?"})
// `You asked me "In one sentence, what is a durable agent run?"`

Inspect what happened, without a server:

bonnie runs list --journal .bonnie
bonnie runs show --journal .bonnie run-1

RUN    STATE      STEPS  LAST
run-1  completed  2      You asked me "In one sentence, what is a durable agent run?"

Park and resume

This is the headline feature. An agent asks a question, your process exits, and a completely new process finishes the job.

BONNIE ships two tools for this. Register them and the model can call them:

Tool	Parks the run to...
ask_human	ask the operator a question
request_approval	get approval before a risky action

runtime.KitAgent registers both automatically.

runner := runtime.NewRunner(journal, runtime.KitAgent(
	kit.WithModel("anthropic/claude-sonnet-4-5"),
	kit.WithSystemPrompt("Before you deploy anything, use ask_human to ask "+
		"which region to deploy to."),
))

run, err := runner.Start(ctx, "deploy-42", runtime.Input{Text: "Deploy the app."})
if err != nil {
	log.Fatal(err)
}

if run.State == runtime.RunWaiting {
	fmt.Println("agent asks:", run.Suspend.Prompt)
	return // nothing is holding compute — the process may exit
}

Later, anywhere, as long as it can read the same journal:

run, err := runner.Resume(ctx, "deploy-42",
	[]runtime.InputResponse{{Text: "eu-west-1"}})

A parked run holds no compute. It costs nothing to wait a week.

See examples/hitl-restart for a runnable version that genuinely calls os.Exit between the two phases:

go run ./examples/hitl-restart -phase ask
# ...process exits, run is parked on disk...
go run ./examples/hitl-restart -phase answer -answer "eu-west-1"

Your own tools

A BONNIE tool is a Kit tool. Pass it through and it joins the sandboxed and human-in-the-loop sets:

type chargeInput struct {
	Amount int    `json:"amount" description:"Amount in cents."`
	UserID string `json:"user_id" description:"Who to charge."`
}

chargeCard := kit.NewTool("charge_card", "Charge a customer's card.",
	func(ctx context.Context, in chargeInput) (kit.ToolOutput, error) {
		// Runs in YOUR process, with your secrets. The model sees only
		// the result you return.
		if err := stripe.Charge(in.UserID, in.Amount); err != nil {
			return kit.ErrorResult(err.Error()), nil
		}
		return kit.TextResult("Charged."), nil
	})

runner := runtime.NewRunner(journal, runtime.KitAgent(
	kit.WithModel("anthropic/claude-sonnet-4-5"),
	kit.WithExtraTools(chargeCard),
))

You can also write a tool that parks the run — that is all ask_human is:

return kit.ToolOutput{
	Content: "Waiting for the finance team.",
	Halt:    true,
	FinalValue: runtime.SuspendRequest{
		Kind:   "approval",
		Prompt: "Approve a $4,000 refund?",
	},
}, nil

The run stops, Start returns with State == RunWaiting, and run.Suspend.Prompt carries your question.

Sandboxing

By default, tool calls run as your process — your files, your network, your credentials. For anything untrusted, put them in a sandbox:

provider := sandbox.Docker(sandbox.WithDockerImage("python:3.12-slim"))

runner := runtime.NewRunner(journal, sandbox.Agent(provider,
	kit.WithModel("anthropic/claude-sonnet-4-5"),
))

The model now gets bash, read_file, write_file, and list_files that run inside a container rooted at /workspace.

Backend	Isolation	You install	Extra Go deps
sandbox.Local()	none — dev only	—	0
sandbox.Docker()	container namespaces	Docker	0
sandbox.Microsandbox()	microVM, guest kernel	msb	0

All three drive a CLI, so BONNIE stays a single static binary.

The microsandbox adapter is verified on Linux with KVM (msb 0.6.18, all 18 conformance cases, network policies enforced with real egress). It has not been run on macOS with Apple Silicon, and its network policy is fixed at create time: reattaching under a different policy fails with ErrPolicyMismatch rather than silently using the old rules.

Lock down the network:

provider := sandbox.Docker()
provider.SetNetworkPolicy(sandbox.NetworkPolicy{Mode: sandbox.NetworkDenyAll})

Pick the best backend available, without silently falling back to no isolation:

provider, err := sandbox.Select(ctx, sandbox.Microsandbox(), sandbox.Docker())

The sandbox opens on the first tool call that needs it, so a parked run holds no container. Read docs/SANDBOX.md before deploying.

Serve over HTTP

bonnie serve --journal .bonnie --model anthropic/claude-sonnet-4-5 --sandbox docker

Or mount it in your own server:

runner := runtime.NewRunner(journal, runtime.KitAgent(opts...))
http.ListenAndServe(":8080", bonniehttp.New(runner).Handler())

Route	Does
POST /runs	start a run, or route to the one serving an address
GET /runs/{id}	report a run's durable state
POST /runs/{id}	send a message to an existing run
POST /runs/{id}/respond	answer a parked run
POST /runs/{id}/cancel	stop the turn in flight
GET /runs/{id}/stream	NDJSON event stream, resumable via ?cursor=

# Start a run. It parks on a question.
curl -s localhost:8080/runs -d '{"text":"Deploy the app. Ask me the region first."}'
# {"run_id":"run-e8b3fa...","state":"waiting",
#  "suspend":{"kind":"question","prompt":"Which region?"}}

# Answer it.
curl -s localhost:8080/runs/run-e8b3fa.../respond \
  -d '{"responses":[{"text":"eu-west-1"}]}'
# {"run_id":"run-e8b3fa...","state":"completed","response":"Deployed to eu-west-1."}

Addresses

Chat platforms have threads, not run IDs. Pass an address and BONNIE keeps the mapping in the journal, so a restart does not orphan a conversation:

curl -s localhost:8080/runs -d '{"address":"slack:C123/T456","text":"hi"}'

The same address always resolves to the same run. POST /runs/{id} is the opposite: it targets one exact run and returns 404 rather than creating one.

CLI

bonnie serve    Mount the HTTP channel and serve durable runs
bonnie runs     List and inspect durable runs
bonnie version  Print the version

bonnie serve --addr :8080 --journal .bonnie \
             --model anthropic/claude-sonnet-4-5 \
             --sandbox docker --sandbox-deny-network

bonnie runs list --journal .bonnie --state waiting
bonnie runs show --journal .bonnie run-1
bonnie runs show --journal .bonnie run-1 --json | jq '.[] | select(.kind=="message")'

runs reads the journal directly, so it works while the server is stopped — which is exactly when you need it.

Storage

The journal is the durability seam. Two ship in the box:

runtime.NewMemoryJournal()          // tests and ephemeral runs
runtime.OpenFileJournal(".bonnie")  // JSONL, one file per run

FileJournal writes <root>/runs/<run-id>.jsonl, one JSON object per line, fsynced by default. It is plain text, so jq works on it:

jq -c 'select(.kind=="message") | {seq, role}' .bonnie/runs/run-1.jsonl

Bring your own by implementing seven methods:

type Journal interface {
	Append(ctx context.Context, rec Record) (seq int, err error)
	Replay(ctx context.Context, runID string) ([]Record, error)
	Checkpoint(ctx context.Context, runID string, state RunState) error
	State(ctx context.Context, runID string) (RunState, error)
	Runs(ctx context.Context, state RunState) ([]string, error)
	Persisted() bool
	Close() error
}

A table-driven conformance suite in runtime/journal_conformance_test.go runs against every implementation. Add yours to it and it inherits the whole suite.

Streaming

Subscribe to a run's events in-process:

events, unsubscribe := runner.Events().Subscribe("run-1", 0)
defer unsubscribe()

for ev := range events {
	fmt.Println(ev.Seq, ev.Type, ev.Text)
}

Or over HTTP, one JSON object per line:

curl -sN localhost:8080/runs/run-1/stream

Every event carries a monotonic seq. If a client drops, reconnect with the last one it saw and lose nothing:

curl -sN "localhost:8080/runs/run-1/stream?cursor=12"

Steer and cancel

runner.Steer("run-1", "actually, use eu-west-1")  // joins the running turn
runner.Cancel("run-1")                            // stops it

Cancelling keeps every completed step, so the run restores to a valid conversation and can be continued with Start.

Run states

pending → running → completed
                  → waiting    (parked for a human; resume with Resume)
                  → cancelled  (stopped by an operator; continue with Start)
                  → failed

How it works

BONNIE is built on four public Kit extension points. No fork, no patched SDK:

Need	Kit API
Journal every message	Options.SessionManager
Checkpoint each step	Kit.OnStepFinish
Inject replayed context	Kit.OnContextPrepare
Park for a human	kit.ToolOutput{Halt, FinalValue}

Three properties are worth knowing, because they are the difference between a demo and something you can deploy:

• Replay is lossless. Journalled messages keep their typed parts, so a resumed run knows which tools it called and what came back. It will not repeat a side effect it already performed.
• A step commits atomically. A tool call and its result reach the journal as one write and one fsync (kit.StepAppender, adopted from Kit v0.106.0), so a crash cannot leave an unanswered tool call. If a torn step still reaches disk — from an older journal, a non-batching journal, or a short write — restore drops that incomplete step and records the repair.
• Cancelling keeps finished work. Steps are persisted before the context is checked, so a cancelled turn loses only the step in flight.

Full detail, with the Kit citations, in docs/SPEC.md.

Limits

Stated plainly, because the failure modes are not obvious:

• Sandboxing is opt-in. Without it, tool calls run as your process.
• Docker is namespaces, not a kernel. Use microsandbox for hostile code.
• microsandbox is verified on Linux/KVM only — not on macOS with Apple Silicon. Every network policy mode is enforced, but the policy is fixed at create time; reattaching under a different policy fails with ErrPolicyMismatch.
• Sandbox egress is open unless you set a policy.
• No auth verification. The HTTP channel carries a Principal; it does not check one. Authenticate in front of it.
• Run ownership is per host. The file journal locks each run with flock, so a second writer to the same run is refused rather than allowed to corrupt it. That lock does not work on a network filesystem, and it does not make two writers coordinate — one process still owns each run.
• Events are journal-anchored. The stream replays the journal past the in-memory backlog, so a reconnect — even after a restart — has no gap. Live-only deltas are the exception, marked as such.
• Sandbox lifecycle is journalled, and reclaiming is manual. bonnie sandbox prune deletes the sandboxes of terminal runs; serve does not sweep them on its own yet.

Examples

Example	Shows
examples/minimal	one durable run, start to finish
examples/hitl-restart	park, exit the process, resume

go run ./examples/minimal -text "What is a durable agent run?"

See examples/README.md for copy-pasteable commands.

Documentation

Document	Purpose
docs/HANDOVER.md	Picking up the project: state, pitfalls, what to do next
docs/SANDBOX.md	Sandbox backends and the contracts an adapter must honour
docs/SPEC.md	Specification: scope, verified Kit facts, known risks, invariants
docs/TASKS.md	Open work, and an archive of what shipped
docs/UPSTREAM.md	Changes BONNIE asks of Kit, with evidence
CONTRIBUTING.md	Boundary rule, workspace setup, commands
SECURITY.md	Disclosure, and what v0.1.0 does not protect you from

Contributing

go build ./...
go test -race ./...
golangci-lint run

The live-model tests are behind a build tag and need a provider key:

go test -race -tags integration ./runtime ./sandbox

They skip, never fail, when no key is present. One rule matters above the rest: BONNIE uses the public Kit SDK only. See CONTRIBUTING.md.

License

MIT — see LICENSE.