Autonomous runs

agent.RunAutonomous is the multi-turn driver for unattended workers — batch jobs, CI tasks, scheduled scripts, anything that needs to keep working after a single agent.Run turn would have ended. It loops agent.Run against a goal, enforces run-level budgets, and stops when the model signals “done” via an internal lifecycle tool.

Two senses of “autonomous” matter here:

This page covers across-turn autonomy. For the within-turn case, see Library API → Streaming events.

Quick example

import (
    adktool "google.golang.org/adk/tool"
    "github.com/go-steer/core-agent/agent"
)

build := func(extras []adktool.Tool) (*agent.Agent, error) {
    return agent.New(m,
        agent.WithInstruction(
            "You are an autonomous worker. Complete the user's goal end-to-end "+
                "without asking clarifying questions. When finished, call "+
                "report_done with state=\"done\" and a one-sentence detail.",
        ),
        agent.WithTools(append(extras, myTools...)),
    )
}

res, err := agent.RunAutonomous(ctx, build,
    "find every TODO comment and write a tracking doc",
    agent.WithMaxTurns(20),
    agent.WithMaxWallclock(10*time.Minute),
    agent.WithPerTurnTimeout(2*time.Minute),
)

The driver returns a structured RunResult{Reason, Turns, InputTokens, OutputTokens, CostUSD, Duration, FinalText, DoneDetail} plus any error.

Constructor pattern

build is a constructor — func(extras []tool.Tool) (*agent.Agent, error) — not an *Agent instance. The driver registers an internal report_done tool and passes it to your build function via extras; you compose it with your own tools and return a fresh agent.

This shape avoids two problems: mutating a caller-supplied agent across runs (which would race), and polluting agent.New’s public surface with “extra tools” plumbing only the autonomous driver needs.

Termination signal

The driver registers a single-purpose tools.LifecycleTool named report_done. The model calls it to end the run. Override the name with WithDoneToolName if it collides with one of your own tools; override the description with WithDoneToolDescription to teach the model when “done” really means done (e.g. “only after writing a summary file”).

Marker-phrase detection (“look for TASK_COMPLETE in the text”) is not supported and not recommended — the model can hallucinate the marker. Tool-based termination is unambiguous.

Budgets

Budgets are evaluated between turns. A turn already in flight when the cap fires runs to completion (or to per-turn timeout) before the driver stops.

Failure policy

By default any turn-level error aborts the run. Install WithRetryPolicy for transient-error recovery:

agent.WithRetryPolicy(func(err error, attempt int) agent.RetryDecision {
    if attempt > 3 { return agent.AbortRun }
    if isTransient(err) { return agent.RetryTurn }
    return agent.SkipTurn
})

AbortRun returns RunResult{Reason: StopReasonRetryAborted} plus the underlying error. RetryTurn re-runs the same prompt. SkipTurn advances to WithContinuationPrompt (default "continue") and treats the failed turn as if it had completed without a done signal.

Permission modes

For unattended runs, use permissions.ModeYolo (or ModeAllow with an explicit allowlist) — ModeAsk would deadlock waiting for a human nobody’s there to be. If you do use ModeAsk, wire a permissions.Prompter that fails fast (e.g. tools.RefusePrompter).

When your build function constructs gated tools, pass the gate to the driver via WithPermissionsGate(g). The driver does a single startup check — Mode==ask && !HasPrompter errors out before invoking build, so you don’t burn an LLM round-trip discovering the misconfiguration. Runtime gating is still enforced by the tools themselves; WithPermissionsGate only enables the deadlock guard.

See Permissions for the underlying gate semantics.

Asking the user during autonomous runs

A real tension: the agent’s instructions might say “always ask before any cluster modification” but there’s no human staring at a REPL prompt. Two patterns work depending on how long the wait might be.

In-turn (the agent waits inside one turn). The agent calls an ask_user tool whose handler blocks until the answer arrives, then returns the answer as the tool result. tools.NewAskUserTool ships this; the bundled CLI exposes it as --ask=stdin|auto|off. Best fit for short clarifications inside a working turn.

Status + new turn (the agent yields between turns). For long waits — human is on lunch, another agent has to finish first — the agent emits a status (a tools.LifecycleTool call that returns immediately) and ends its turn. A driver loop on the consumer side reads the next input from wherever and starts a fresh agent.Run.

The bundled prompters cover the common shapes:

Crash-resume

When the agent is wired with WithEventLog, RunAutonomous emits a checkpoint event after every turn (and a final checkpoint with stop_reason on loop exit). A later ResumeAutonomous call against the same session walks the event log, re-derives the run totals from the latest checkpoint, and continues from the next turn.

import (
    "github.com/glebarez/sqlite"
    "github.com/go-steer/core-agent/agent"
    "github.com/go-steer/core-agent/eventlog"
)

handle, _ := eventlog.Open(ctx, sqlite.Open("/path/to/sessions.db"))
defer handle.Close()

// Phase 1: original run, capped at 5 turns.
res1, _ := agent.RunAutonomous(ctx, build, "the goal",
    agent.WithMaxTurns(5))
// ... process exits, machine reboots, whatever ...

// Phase 2: pick up where Phase 1 left off.
res2, _ := agent.ResumeAutonomous(ctx, resumeBuild,
    agent.SessionRef{
        Handle:    handle,
        AppName:   "my-app",
        UserID:    "alice",
        SessionID: "long-running-task",
    },
    agent.WithMaxTurns(20))

ResumeBuildFunc differs from RunAutonomous’s BuildFunc in one detail — it receives the resumed session ID so the constructed agent rejoins the same session via agent.WithSession:

resumeBuild := func(extras []adktool.Tool, sess string) (*agent.Agent, error) {
    return agent.New(m,
        agent.WithAppName("my-app"),
        agent.WithSession("alice", sess),
        agent.WithEventLog(handle),
        agent.WithTools(extras),
    )
}

Behavior worth knowing:

• Terminal short-circuit only on Completed. A checkpoint with stop_reason == "completed" (the model called report_done) returns the stored RunResult immediately. Other stop reasons (max_turns_exceeded, wallclock_exceeded, context_cancelled, retry_aborted) are interruptions, not terminations — those resume normally with carried-forward totals.
• No-checkpoint = turn-0 start. A session with no /autonomous-suffix checkpoints is treated as a fresh start. “Take this existing conversation and make it autonomous from here” is a valid use.
• Cross-binary resume. Checkpoints carry Author = "<binary>/autonomous" (from os.Executable()). Discovery filters by the /autonomous suffix so a run started under core-agent can be resumed under scion-agent or ax-agent without losing its trail.
• Budgets carry forward. WithMaxTurns(3) on resume against a session that already used 3 turns fires the pre-turn budget check immediately. Pass a higher budget to extend.
• Session lock. ResumeAutonomous takes an exclusive lease on (AppName, UserID, SessionID) for its lifetime; concurrent attempts return eventlog.ErrSessionLocked with the holder identifier in the error message. See Sessions → Session lock.

examples/autonomous-resume/ runs end-to-end with no credentials — uses the scripted mock provider, drives a Phase 1 run capped at 2 turns, then a Phase 2 resume that completes the task.

Lifecycle tool for state emission

tools.NewLifecycleTool is the generic state-emission primitive the autonomous driver uses internally for its report_done signal. It’s also exported for direct use — orchestrator adapters (Scion, AX) wire it for “I’m thinking / blocked / done” emission to their UI even though they have their own loops.

import "github.com/go-steer/core-agent/tools"

statusTool, _ := tools.NewLifecycleTool(tools.LifecycleOptions{
    Handler: func(ctx context.Context, ev tools.LifecycleEvent) error {
        log.Printf("agent status: %s — %s", ev.State, ev.Detail)
        return nil
    },
})

AllowedStates constrains what state labels the model can emit; the autonomous driver uses []string{"done"} to scope its internal instance. Consumer-supplied handlers route emissions wherever they need to go — stderr, a status file, a websocket, an orchestrator’s event log.

Subagents

For tasks where the model should delegate focused work to a specialized agent (research, planning, summarizing), wire one or more subagents via agent.WithSubagents([]*Agent):

research, _ := agent.New(researchModel,
    agent.WithName("research"),
    agent.WithEventLog(handle),
    agent.WithInstruction("you are a researcher; answer concisely"),
)
parent, _ := agent.New(parentModel,
    agent.WithEventLog(handle),
    agent.WithSubagents([]*agent.Agent{research}),
    agent.WithInstruction("delegate fact-finding to the research subagent"),
)

The parent’s model sees a research tool it can call with a request string. The handler dispatches the inner agent’s runner; the joined final text comes back as the tool result. Subagent events stream live into the parent’s audit log under Branch="<parent_branch>.research".

See Library API → Subagents for the full API surface — depth caps, custom branch labels, per-subagent options. examples/with-subagent/ runs end-to-end with no credentials.

Composition with recording and mock providers

Both layers compose transparently. To record a run for offline replay, wrap the model before passing it into build:

m = recording.NewRecorder(m, recordFile)
build := func(extras []adktool.Tool) (*agent.Agent, error) {
    return agent.New(m, agent.WithTools(extras))
}

To test the loop without burning quota, drive RunAutonomous against a mock.NewScripted(...) model. examples/autonomous/ runs end-to-end this way with no credentials.

What’s deferred

• Pause / resume mid-run. The orchestrator-driven pattern (Scion, AX) covers this naturally; standalone needs more design.
• Streaming structured results. WithProgress(callback) covers per-event observation today; richer shapes will land when a consumer asks.
• --autonomous CLI flag. The bundled cmd/core-agent is a REPL / one-shot tool. Long-running autonomous use is a library / script concern.