--- title: Durable Agent Runtime description: State & durability lens of agent infrastructure — durable objects (celld), actors (rivet), multi-hypervisor VM runtimes (hypeman, E2B/Amp Orbs), scale-to-zero/hibernation — and what they mean for building a self-hosted orb-like runtime on hermes-vm. Sibling of harness-engineering under the agent-infra umbrella. status: active category: technical tags: [durable-objects, actors, agent-runtime, agent-infra, sandbox, microvm, self-hosting, orbs, stateful, durable-execution] draft: true created: 2026-08-07 updated: 2026-08-11 origin: buzz://d8a718be-031f-4a6e-9f5c-a55466641654/4123d35532d0b2cbfb80a0a34f79fb3e4e63c16c25b77d43bc0f10bb178e4f1b --- # Durable Agent Runtime ## Summary Research into how modern agent execution environments achieve **durability and statefulness** — where agent state lives, what compute primitive runs the agent, and how the environment hibernates and wakes. Covers durable objects / durable execution (celld, rivet, Durable Objects), actor runtimes, and microVM sandboxes (hypeman, E2B/Amp Orbs). The harness/loop lens (nanocodex, pi, Code Mode) now lives in [[harness-engineering/index|Harness Engineering]]. Goal: derive a build plan for a self-hosted, orb-like runtime on our NixOS VM (hermes-vm) without overbuilding. ## Research Question What are the architectural primitives for a durable, stateful agent runtime (sandboxed or not), and which combination fits a single self-hosted NixOS dev VM? ## Scope - Included: durable objects / durable execution (celld, rivet, Durable Objects), actor runtimes, sandbox/VM runtimes (hypeman, E2B, Cloudflare isolates), scale-to-zero/hibernation, orbs - Excluded (moved): agent harness/loop engineering → [[harness-engineering/index|Harness Engineering]]; model training/inference infra, prompt engineering, RLHF - Sufficient answer: a taxonomy of primitives + a recommendation for what to build (and what NOT to build) on hermes-vm ## Key Findings - **The 2026 pattern is unanimous**: agent compute is disposable, agent state is durable elsewhere. Amp: sandbox is ephemeral, the thread (prompts, tool calls, results) lives on the server. celld: nodes are replaceable, the S3 bucket is the source of truth. Rivet: actor state persists while the process may hibernate. - **Three primitive families emerged** (harness libraries split out to [[harness-engineering/index|Harness Engineering]]): 1. Durable object/execution stores — celld (each object = its own SQLite DB, S3 replication, no consensus) 2. Actor runtimes — rivet (in-memory state + persistence, ~20ms cold start, scale to zero, queues/workflows/scheduling) 3. Sandbox/VM runtimes — hypeman (multi-hypervisor OCI-in-VM), E2B (Firecracker microVMs, snapshot restore, used as Amp's orb substrate) - **Scale-to-zero / hibernation is universal**: Amp orbs pause after 5 min idle; celld cells hibernate; rivet actors hibernate when idle; hypeman standby = snapshot VM to disk, resume in milliseconds; E2B snapshot reuse gives sub-30ms cold starts. - **Two hard problems everyone solves**: (a) cold start latency (actor ~20ms vs VM ~30s, mitigated by snapshot/pooling), (b) state checkpointing and recovery (SQLite replication, thread JSONL, VM snapshots, actor state persistence). - **For our stack**: hermes-vm is already a durable compute host (systemd services, kanban DB, session DBs, herdr panes). The real gap is a per-task disposable environment contract + event wake, not a distributed state layer. celld/rivet solve problems we don't have on a single box; hypeman is interesting for per-task VMs but likely overkill. ## Sources For the full reference list see [[durable-agent-runtime/sources|Sources]]. ## Detail Files - [[durable-agent-runtime/sources|Sources]] — full reference list - [[durable-agent-runtime/analysis|Analysis]] — taxonomy, comparison matrix, implications for our build - [[durable-agent-runtime/agent-collaboration|Agent-Native Collaboration]] — agents as first-class signed participants (Radicle COBs / delegates / namespaces) - [[durable-agent-runtime/next-steps|Next Steps]] — follow-up questions and build plan ## Related Research - [[agent-infra/index|Agent Infrastructure]] — umbrella topic - [[harness-engineering/index|Harness Engineering]] — agent loop & tool interface lens (split out 2026-08-11) - [[codex-app-server-byo-auth/index|Codex App Server & BYO Auth]] — model access & embedding protocols - Amp Orbs research note (workspace): `RESEARCH/AMP_ORBS_REMOTE_DEV.md` - Prime Agent / Continual Harness (arXiv 2605.09998) — self-improving harness state ## Discussion Triggered from the Amp Orbs thread (2026-08-07). User connected the dots: orbs, nanocodex, durable objects (celld), actors (rivet), multi-hypervisor VM runtimes (hypeman), and Cloudflare Code Mode all belong to one research area — "durable object, stateful machine, harness engineering either sandboxed or not." Asked for centralized structured research he can digest. Completed directly (all primary sources already extracted; delegation channel has known instability). On 2026-08-11 the topic was narrowed to the state/durability lens and placed under the agent-infra umbrella; harness engineering split out. ## Next Steps - [ ] Decide Phase 1 scope: per-repo `.agents/setup`-style contracts + AGENTS.md per repo on hermes-vm - [ ] Evaluate hypeman as an opt-in per-task VM runtime (snapshot/standby) vs NixOS containers ## Conclusion The research area is **durable, stateful agent runtime — sandboxed or not**. Three primitive families cover the space; for a single self-hosted NixOS VM the right move is environment contracts + event wake on the existing durable host, not building a distributed durable-object layer. The tool-interface half of the original question now lives in [[harness-engineering/index|Harness Engineering]].