Durable agent run resume

This example shows the agent-side counterpart to examples/flow-durable: an agent run is checkpointed with the same Checkpoint interface used by flows, then resumed after an interruption without repeating a completed side effect. The sample uses an in-memory store to keep repeated local runs deterministic; use your service store for process-restart recovery.

Run it with:

go run ./examples/agent-durable

The demo model calls inventory.reserve, then fails to mimic a process dying after the tool call was checkpointed. micro.AgentPending finds the unfinished run and micro.AgentResume continues it from the saved checkpoint. The final tool executions: 1 line is the important bit: the reservation tool was not called a second time during resume.

When to use this instead of a durable flow

Use a durable flow when the path is known ahead of time: ordered service calls, retries, timers, compensation, and a precise resume stage such as reserve or charge. Use a checkpointed agent run when the path is open-ended and the model may choose tools dynamically, but completed tool side effects still must not be replayed after a crash or provider failure.

They compose: keep deterministic business process in flow-durable, then hand off the judgment-heavy step to a checkpointed agent when the workflow needs model-directed tool use. Both use the same Checkpoint backend, so inspection and recovery can share one run-history store.

In a service, use the same pattern at startup:

pending, _ := micro.AgentPending(ctx, agent)
for _, run := range pending {
    _, _ = micro.AgentResume(ctx, agent, run.ID)
}

context.Context cancellation and deadlines are still honored by checkpoint loads/saves, model calls, and tool calls. Runs with terminal statuses such as done, canceled, and expired are not returned by AgentPending.