The VMs Powering Mobile Agents (Instinct, Claude Code)

# The box an agent runs in — Rohan Adwankar Source: [https://rohanadwankar.github.io/posts/platforms.html](https://rohanadwankar.github.io/posts/platforms.html) One awesome product evolution is that agents \(Claude Code, Instinct, Poke, etc\) are moving off our local computers so that we can use them on our phones\. Ultimately this is great for the customer because that means the agent companies provide us with VMs for them to run on\! Here's some notes on how the major platforms work based on looking around on[ws\-term](https://github.com/RohanAdwankar/ws-term)\. ## Claude Code on Your Phone Claude Code's box is its own**Firecracker microVM**, a KVM guest with its own kernel, booted straight into an init written in Rust: ``` $ cat /proc/cmdline ... rdinit=/process_api ... --listen-vsock-port 2024 $ uname -r 6.18.5-fc-v20 # -fc- = Firecracker; a custom-built guest kernel $ ps -o comm -p 1 process_api # PID 1 is not systemd; it's a Rust/Tokio binary ``` `process\_api`is PID 1 and the host's control agent living inside your VM: it mounts the disks, then listens on**vsock port 2024**so the host can drive the session from outside\. That's the platform's defining trait:**the operator lives inside your tenant space**, and a lot of engineering goes into sealing it off \(PID 1 is non\-dumpable,`/proc/1/mem`is denied even with`CAP\_SYS\_PTRACE`, your shell is missing`CAP\_SYS\_RESOURCE`\)\. The disks split cleanly into*yours*\(writable, persistent\) and*theirs*\(read\-only, shared\): ``` $ lsblk -o NAME,SIZE,RO,MOUNTPOINT vda 256G 0 / # yours: writable, survives reclaim vdc 341M 1 /opt/claude-code # theirs: the 324 MB `claude` harness (Bun) vdd 45.6M 1 /opt/env-runner # theirs: the task launcher vde/vdf ... 1 /mnt/skills/... # theirs: skills ``` The**harness**is the thing running your tool calls and is a 324 MB compiled Bun binary on a read\-only disk\. The model runs elsewhere; inference goes out as**Server\-Sent Events over HTTPS/2**\(not a WebSocket\) to`/v1/messages`, through an egress gateway that is 443\-only and MITM'd \(`CN = Egress Gateway \.\.\. \(production\)`\), with`api\.anthropic\.com`pinned in`/etc/hosts`\. There is no inbound at all \(`192\.0\.2\.2`, an RFC\-5737 test address\)\. Auth is a**host\-minted OAuth token**, cached root\-only on disk and rotated per boot\. Lifecycle is host\-driven and measured from the inside:**~430 ms**to init,**~6\.4 s**to the harness process\. Spin\-up is triggered by an inbound message \(the host wakes the VM over vsock and runs`\-\-session\-mode resume`\); spin\-down is idle reclaim decided by the host\. When it's reclaimed, the*processes*die but`vda`detaches intact and reattaches on the next cold boot, which is why the conversation feels continuous even though the compute was destroyed\. ``` flowchart TB user(["your keystrokes"]) -->|http post| ingress["session-ingress"] ingress --> pa hostctl(["host control plane"]) -->|vsock port 2024| pa subgraph vm["Firecracker microVM"] pa["process_api, pid 1, Rust"] --> harness["claude, 324 MB Bun harness"] vda[("vda (rw), yours, persists")] --- harness ro[("vdc/vdd/vde/vdf (ro), theirs")] --- harness end harness -->|inference over SSE| gw["egress gateway, 443, mitm, api.anthropic.com"] ``` ## Instinct Instinct is a new startup which launched recently and it does some very nice things on the memory side which gives that feel of it being a real assistant rather than a chatbot\. ``` $ hostname e2b.local $ cat /.e2b n038afjvewg7jnc9pwdz ``` `e2b\.local`means Instinct doesn't operate its own VM fleet; it rents[E2B](https://e2b.dev/)sandboxes \("sandbox\-as\-a\-service"\), a throwaway Ubuntu box you hand an agent so it has a computer: ``` Ubuntu 22.04.5, 2 vCPU, 1.9 GB RAM, 29 GB disk, up ~30 min, user sandbox (uid 1001) ``` And let's look under the hood\.\.\. ``` $ systemd-detect-virt → kvm $ cat /proc/cmdline pci=off virtio_mmio.device=4K@... i8042.noaux i8042.nokbd reboot=k panic=1 clocksource=kvm-clock root=/dev/vda ip=169.254.0.21::...:eth0:off:tap0 $ cat /sys/class/dmi/id/product_name → (empty) # no SMBIOS at all $ ps -o comm -p 1 → systemd # init=/sbin/init, not a custom PID 1 ``` Firecracker again\! `pci=off`\+ virtio\-over\-MMIO \+ empty DMI \+`tap0`networking is the Firecracker signature: no PCI bus, no SMBIOS, minimal devices\. So both apps sit on the*same*microVM; the difference is who runs the fleet and**what boots inside it\.**Where Claude Code boots a stripped custom init \(`process\_api`as PID 1\), E2B boots a full Ubuntu with systemd and a whole XFCE desktop: ``` $ systemd-analyze Startup finished in 265ms (kernel) + 992ms (userspace) = 1.258s graphical.target reached after 977ms ``` ~1\.26 s to cold\-boot all the way to a graphical desktop\. The operator\-in\-guest exists here too, but it's just E2B's`envd`running as an ordinary systemd service, not a sealed PID 1\. E2B sandboxes are configurable too \(you pick the vCPU, RAM, disk, and idle timeout, and whether the box can be paused and resumed from a memory snapshot instead of cold\-booted\); Instinct runs a modest 2 vCPU / 1\.9 GB desktop template\. So if the box is disposable, where does the agent's memory live? In a directory called`/memory`, and this is the platform's defining idea: ``` $ cat /memory/README.md Persistent memory for [[rohan-adwankar]] $ ls /memory entities/ comms/ timeline/ workstreams/ knowledge/ $ git -C /memory log --format='%an <%ae>' -1 Instinct Agent <[email protected]> ``` The agent's memory is a**git repo of Markdown files**with`\[\[wiki\-links\]\]`, navigated by`grep`\. The`timeline/`*coarsens*over time \(raw → hourly → daily → weekly, like human memory\), and the agent is literally the**git author**: it doesn't call a memory API, it writes Markdown and commits it as itself\. The durable layer is that repo, pushed to**S3**, keyed by a per\-user id, and stored not as files but as a single**git bundle**, which is a great little gotcha: ``` $ git -C /memory remote -v origin s3://instinct-prod-agent-memory/filesystem-memory/user-01M1VW7... $ aws s3 ls s3://.../user-01M1VW7.../ --recursive HEAD refs/heads/main/<sha>.bundle # the ENTIRE vault, packed; `ls` after sync looks empty ``` Auth is**short\-lived STS credentials**, not long\-lived keys, so a leaked sandbox self\-heals when the token lapses: ``` $ cat /etc/instinct-aws-creds export AWS_ACCESS_KEY_ID='ASIA…' # ASIA prefix + session token = temporary STS ... # (values redacted, live secrets) # role: instinct-sandbox-observations-role ``` ``` flowchart TB subgraph box["E2B sandbox (rented, disposable)"] agent["Instinct Agent ([email protected])"] -->|writes and commits| mem["/memory, a Markdown vault git repo"] creds["/etc/instinct-aws-creds, short-lived STS"] end mem -->|git push| store creds -->|authorizes git push| store subgraph store["S3 (durable, per-user)"] vault[("instinct-prod-agent-memory, the vault")] obs[("instinct-prod-observations, raw firehose")] end ``` *Durable thing = a git repo in S3\. The machine is throwaway\.* Using a git repo for this is quite nice; the default structure seems to be like this: ``` ~/instinct-vault/.. │󰫎 24 󰲡 Vault   .git │ 23   comms │ 22 Persistent memory for 󱗖 rohan-adwankar. Markdown + wiki-links, navigated by grep. Start here, then jump   chat │ 21  rohan-adwankar--inst│ 20 Who Rohan is, what he is working on, and what is connected live in entities/, workstreams/, and knowled   entities │ 19   people │󰫎 18 󰲣 Layout  rohan-adwankar.md │ 17   projects │ 15 README.md  ws-term.md │ 14 timeline/ chronological record, coarsening upward: raw/ → hourly/ → daily/ → weekly/ → monthly/   knowledge │ 13 entities/ people/ projects/ — the nouns of Rohan's world, one file each   decisions │ 12 comms/ chat/ email/ meetings/ — one file per thread, named <who>--<topic>--<date>.md  x-account-signup-dec│ 11 workstreams/ active/ completed/ someday/ — units of work; status: frontmatter matches the subdirectory   preferences │ 10 knowledge/ facts/ procedures/ preferences/ decisions/   instinct │ 8  autonomy.md │ 7 knowledge/preferences/instinct/ holds how Rohan wants the assistant itself to behave — autonomy, drafti  iteration-style.md│ 6   timeline │󰫎 5 󰲣 Conventions   daily │ 4  2026-09-06.md │ 3 ● Every file has frontmatter with id, type, and aliases. [[id]] resolves to id.md or id/_index.md.   workstreams │ 2 ● Entity and knowledge files are updated in place and read as current state, never as a log. History li   active │ 1 ● Files that outgrow one page are promoted to a directory with an _index.md carrying the original id.  dragon-game-asset.md│ 25 - Timeline and comms hold events and conversations; entities hold durable properties only.  startup-idea-search.│~ 󰂺 README.md │~ ~ │~ ~ │~ :!tmux capture-pane -pS - | pbcopy ``` Now Claude Code's harness in the VM is open source and the same as normal but how about Instinct? ``` $ ps -eo args | grep -E 'agent-exec|tools' agent-exec-server --port 8080 # Go, runs the bash/code it's sent tools __internal_daemon --socket /tmp/.tools/bridge.sock \ --base-url https://api.instinct.com/-/api/graphql/tool-execute # Rust $ strings /usr/local/bin/tools /usr/local/bin/agent-exec-server \ | grep -iE 'anthropic|openai|/v1/messages|x-api-key|claude|gpt|model' # → nothing. no model listed ``` So it seems like there are no inference calls anywhere on the box\. Claude Code seals the*operator*inside the guest; Instinct doesn't put the brain in the guest at all\. The sandbox is a pure**execution surface**:`agent\-exec\-server`runs whatever bash the backend hands it, and every tool call \(Gmail, the cloud browser, a payment\) leaves as a**GraphQL request to`api\.instinct\.com`**, executed server\-side\. The`\-\-base\-url`is a runtime argument, not compiled in\. For the actual tool surface, rather than MCPs, Instinct seems to use a CLI for all tools: ``` sandbox@e2b:~/ws-term-v1$ tools --help | wc 90 1466 10891 sandbox@e2b:~/ws-term-v1$ tools --help Tools CLI You are a task agent. Your parent (the main agent) spawned you for a focused job. When the job is done, report back to your parent and hold. Your parent owns task-agent cleanup. Your direct-execute traits: - work - integrations, files, web page fetching .... Run `tools --help` for the current surface. USAGE tools <command-path> [options] tools help [<path>...] .... Built-ins (no help read needed): help, async wait, async list. EXECUTABLE (you can call these directly) agent_message namespace (1 action) Send messages to other agents. browser_guidance namespace (3 actions) Search per-config website guidance and this user's past outcomes before browser navigation, and record how a config performed after an attempt. Missing guidance is normal and means unknown, not supported or blocked. cloud_browser namespace (27 actions) Drive a cloud-hosted Chrome lease with the user's saved logins. Use for agent-driven web tasks (order food, book rides, compare prices, fetch receipts) that need real authenticated capability on real sites. A task agent acquires its own `lease_id` with `tools cloud_browser_scheduler acquire` and drives it here. .... DELEGATED (only callable by the other role) account namespace (2 actions) Read the user's Instinct account profile. feedback namespace (3 actions) Submit product feedback and respond to team follow-ups. generate_referral_link action Ask the main agent to get the member's reusable referral link and current lifetime allowance. revoke_referral_link action Ask the main agent to revoke the member's reusable referral link. speak action Generate a WAV speech file from a transcript, optional director's notes, and a voice. UNAVAILABLE (does not apply to this role) steer_voice_agent action Send an answer or context into the user's active live voice session. ``` The tool surface is the tell that this box isn't a coding sandbox at all\.`tools \-\-help`lists ~50 namespaces \(Gmail, Notion, Slack, Stripe payments, a credential vault\), but the one that reveals the design is the**cloud browser**: ``` $ tools --help | grep -iE 'cloud_browser|vault' cloud_browser (27) Drive a cloud-hosted Chrome lease with the user's saved logins. cloud_browser_scheduler (4) acquire, list, release, extend leases vault (7) Manage, fill, and import the user's stored credentials ``` When Instinct orders food or books a flight "as you," it does**not**open a browser on this sandbox\. It*leases*one from a separate pool of cloud browsers, each carrying your saved profile \(cookies and logins\) and drives it through the same`api\.instinct\.com`bridge: ``` tools cloud_browser_scheduler acquire # → lease_id, on a browser "config" (a profile) tools cloud_browser <action> # click / type / read / screenshot that Chrome ``` You can read the whole model off how leases behave: each profile has exactly**one write lease**\(the only session allowed to save new logins\), up to five run at once, and releasing a lease "saves its cookies first, so the next lease loads them\." That persistence is the point: your browser identity is a**third durable thing**, sitting server\-side next to the S3 vault and the observations index, kept so a disposable box can borrow it for one task and hand it back\. Two details let it sign in without a secret ever touching the box: - **Scout before navigating\.**`tools browser\_guidance search`returns curated per\-site notes plus*your own*past outcomes per profile \(`config\-a: success`,`config\-b: blocked`\), a risk prior, not a verdict\. - **Secrets go through the Vault, never chat\.**`tools vault fill`types a stored credential straight into the page; when the vault lacks one,`tools vault request`mints a link*you*fill \(`app\.instinct\.com/vault/fill?t=…`\)\. One\-time codes it reads itself from your connected Gmail or Outlook\. ``` flowchart TB ta["task agent, off-box"] -->|acquire lease| sched["cloud_browser_scheduler"] sched --> cb ta -->|click, type, read| cb["cloud browser with your saved profile"] vault[("Vault, your secrets, server-side")] -->|fill| cb cb -->|"logged in as you"| sites(["Amazon, Uber, airlines, and more"]) box["disposable E2B box"] -->|"issues tools calls, holds no cookies"| cb ``` ## Summary **Claude Code****Instinct**Isolation primitiveFirecracker microVM \(KVM\)Firecracker microVM \(KVM\)Who runs the fleetAnthropic, its ownE2B, rented, third partyGuest inside the VMStripped custom init \(`process\_api`\)Full Ubuntu \+ systemd \+ XFCE desktopCold boot \(measured\)~430 ms init, ~6\.4 s to harness~1\.26 s to graphical desktopWhat's durableThe machine \(`vda`block volume\)A git repo in S3Memory modelConversation state on diskMarkdown vault, git\-versioned, agent\-authoredCredentialsHost\-minted OAuth, on disk, rotatedShort\-lived STS, role\-scopedBacking storeLocal virtio\-blockS3, keyed by per\-user idHarness locationOn the box \(324 MB Bun binary\)Off the box; the box holds two execution shimsHow the model is reachedSSE to`/v1/messages`via egress gatewayNever from the box; GraphQL to`api\.instinct\.com`, server\-side This was pretty fun to take a peek, and I'll keep recording my notes as new products come around\!