felhom-agent/CLAUDE.md

CLAUDE.md — felhom-agent

Loads when Claude Code touches this repo. Stable orientation only — current state lives in CONTEXT.md and the top of CHANGELOG.md, never here. Cross-repo orientation: workspace-root /mnt/5_hdd/felhom.eu/git/CLAUDE.md.

What this repo is

felhom-agent is the operator-tier host agent that runs on each Proxmox host and owns all Proxmox interaction: provision/restore guests, host storage, backup/restore orchestration, the hub control loop, and a narrow per-guest local API. It is the most privilege-sensitive component.

• Renamed former proxmox-controller repo.
• Distinct from felhom-controller — that is the in-guest controller (Docker-only, no Proxmox creds). Do not confuse them.
• Control plane, not data plane: if the agent dies, apps keep serving; only management degrades.

Read before writing code

• REUSE.md — canonical helpers, format-safety guards, traps, seams. Check it first; update it in the same commit that changes a shared helper or pattern.
• CONTEXT.md (current state + open threads) and the top CHANGELOG.md entry (authoritative history).
• Design doc: felhom.eu/documentation/architecture/03-host-agent.md (locked). Platform facts: felhom.eu/documentation/proxmox-platform.md + tests/phase{0,1-2,3,4}-findings.md.

Layout (verified against the tree)

cmd/felhom-agent/    main + flags + --selftest modes + the daemon entry
cmd/felhom-opsign/   offline operator signing CLI (SSHSIG)
internal/authz/      operator signed-op verifier (SSHSIG) + durable FileNonceStore
internal/backup/     vzdump backup runner + restore-test scheduler + report store
internal/capability/ live sudo-policy capability probe (degradation visibility)
internal/config/     JSON config + FELHOM_AGENT_* env overlay; secrets redacted (Redacted())
internal/desired/    hub desired-state syncer (envelope observer)
internal/escrow/     PBS-key escrow (zero-knowledge recovery code)
internal/guesthook/  pre-start self-heal hookscript install
internal/hub/        daemon: HostReport collector + Bearer client + resilient Loop
internal/lanresolver/ split-horizon DNS on guest IP change (dnsmasq RESTART, not reload)
internal/localapi/   per-guest local API: token store, disks/format, guest binds, controller swap,
                     stale-lock recovery, pinned self-signed leaf
internal/log/        slog setup
internal/pbs/        PBS-API client (fingerprint-pinned) + verify maintenance loop
internal/provision/  guest bootstrap back-half (token mint → bootstrap.json → pct bind)
internal/proxmox/    API-first Client + fenced root-CLI Privileged + UPID WaitTask
internal/reconcile/  reconcile engine + reversibility gate + op journal + crash recovery
internal/signedjobs/ operator-signed destructive executors (wipe, decommission)
internal/storage/    storage observer + durable ids + role/claim classifiers + SudoHostOps + watchdog

Build / run

• Module gitea.dooplex.hu/admin/felhom-agent; binary felhom-agent (cmd/felhom-agent/).
• Pure Go stdlib + golang.org/x/crypto only — no web frameworks. go.mod directive go 1.25.0; DooPlex (192.168.0.180, where CC runs) has the Go toolchain and is on the same LAN as the demo host — build and run live tests locally.
• Version via -ldflags "-X main.version=<v>"; --version flag. Bump on meaningful changes + CHANGELOG entry.
• Full build/deploy/publish runbook: use the felhom-build-deploy skill. Summary:

Clean-tree gate before any build: git status --porcelain must be empty and git rev-parse HEAD must equal git rev-parse origin/main in the repo being built. An unpushed change does not exist — never build a dirty or unpushed tree. The git pull in the build step stays (it is a no-op when you work in this tree, and load-bearing if anything was pushed from elsewhere).

Step	Where	One-liner
Build	DooPlex (local)	cd /mnt/5_hdd/felhom.eu/git/felhom-agent && git pull && go build -ldflags '-X main.version=<v>' -o /tmp/felhom-agent-<v> ./cmd/felhom-agent
Copy	local → felhom-pve	scp /tmp/felhom-agent-<v> felhom-pve:/tmp/ (one hop)
Deploy	felhom-pve	backup .bak-<old> → install -m0755 → systemctl restart felhom-agent (non-root felhom-agent user, config /etc/felhom-agent/agent.json)
Ship configs	felhom-pve	sudoers (/etc/sudoers.d/felhom-agent) + guarded-mkfs wrapper WITH the binary when configs/ changed
Publish	DooPlex (local)	scripts/publish-agent.sh <ver> <bin> (REGISTRY_* creds); hub Day-0 manifest vouch = operator follow-up
Verify	felhom-pve	felhom-agent --version + journal (clean ReassertGuestBinds, no capability degradation)

Proxmox model (the load-bearing rules)

• API-first via a scoped FelhomAgent token. Raw root-CLI is fenced to exactly 3 exceptions: keyctl pct create (golden image), USB mount/fstab, SMART/sensors. Client never shells out; Privileged never makes HTTP calls (asserted by routing_test.go). Keep that fence.
• Every mutating op is async → returns a UPID → WaitTask asserts exitstatus == "OK". A 200 on the POST is not success; authorization can fail at task execution.
• TLS: SHA-256 leaf-cert pinning (self-signed host cert). No insecure default.
• Privsep token gotcha: a --privsep 1 token's rights = intersection of the backing user's perms AND the token's ACLs — the role must be granted on both, or every call 403s.
• Destructive ops go through the reconcile gate / signed-jobs path — never call Client.DestroyLXC/ Vzdump/SetConfig ad-hoc (REUSE.md §3).

Demo host (for live tests)

Node demo-felhom, API https://192.168.0.162:8006. SSH alias felhom-pve (root@pam) — available to CC as plain ssh felhom-pve. A second demo node demo-hp (HP t740, node name felhom-host, ssh demo-hp — no baked key; break-glass root via hub host_recovery/demo-hp-bb76ea + sshpass) is the designated drill+build VM host per the 2026-07-25 operator ruling, and that ruling is realized — it hosts drill VM 300 (drill-r50), so start there, not on DooPlex. (The historical golden-bake drill.qcow2 still lives on DooPlex and is a bake fixture, not a drill target.) Which box is safe to break, and what may be done to each: felhom.eu/documentation/runbooks/target-selection.md — read it before any destructive test. Both nodes + the break-glass recipe: felhom.eu/documentation/operations/nodes.md. The agent pins the served leaf cert — verify the fingerprint still matches before a live run. Selftest modes (run locally on DooPlex, pointed at the demo API): --selftest[=read|task|hub|storage|backup|restore-test|pbs-verify]; no flag = the daemon.

TEMPORARY — felhom-pve is at a remote site (until ~2026-08-02). The home-LAN literal 192.168.0.162 is NOT reachable from DooPlex for the duration. Access via Tailscale: felhom-pve = 100.70.170.35; the Host felhom-pve entry in ~/.ssh/config on DooPlex already points there (the direct-LAN path stays available as Host felhom-pve-lan). Delete this block on return. All documented ssh felhom-pve / pct exec workflows are unchanged. Path is direct (not DERP), ~37 ms rtt per hop. At the remote site the host is on DHCP; re-check its address rather than trusting one written here (ip -br addr show vmbr0 — it read 192.168.0.162/24 on 2026-07-30, and felhom-pve-lan from DooPlex is still No route to host). Details + findings: felhom.eu/documentation/audits/AUDIT-vacation-remote-ops-2026-07-20.md

The "agent does not run at the remote site" warning this block used to carry is RETRACTED (2026-07-30) — it was true before R-50 and is false now. localapi no longer binds a LAN literal: since the R-50 island migration (2026-07-25) it binds 169.254.253.1:8443 on vmbr9, which is location-independent by design, and proxmox.endpoint is https://127.0.0.1:8006. Verified live: systemctl is-active felhom-agent → active, felhom-agent --version → 0.115.0, and the per-guest local API answered GET /disks over the island. No config edit and no Viktor GO are outstanding.

Legacy: Windows workstation. Until 2026-07-19 CC ran on Windows 11; pct commands over SSH needed export MSYS_NO_PATHCONV=1, and every remote command used SSH=/c/Windows/System32/OpenSSH/ssh.exe. Agent deploy was a two-hop copy via the Windows box (cygpath -w for the local scp path; CRLF hazard on config files).

Conventions

Trunk-based — no branches

All shippable work commits directly to main; main equals what is deployed.

• Report-only artifacts (audits, findings, fixspecs) → felhom.eu/documentation/ (audits/, backlog/).
• Risky/supervised fixes are spec'd, then implemented during the supervised session, on main.
• Unattended escape hatch: if a fix can't be cleanly verified/shipped, revert + report — never park on a branch.

In every repository where you make a change, update both files in that repo:

• CHANGELOG.md — cumulative log, newest on top.
• REPORT.md — overwrite with the most recent implementation/validation summary only.

Never write secrets into any committed file — reference them as "stored out-of-band".

• Code quality: verify generated code for bugs/edge cases; add debug logging; ask rather than guess when you'd otherwise invent input/output.
• A health check issues no block I/O — no statfs, no getdents, no read, write or fsync, not even behind a timeout. Liveness is decided from /proc and kernel state. The full rule + the measurement lives in felhom.eu/CLAUDE.md "Code quality rules"; it is repeated here because health checks are written in THIS repo and that file does not load in an agent-only session. R-117 spike §6.3.
• Update REUSE.md if you added/changed/deprecated a shared helper or pattern (same commit).
• Testing doctrine (non-hollow tests, red-proofs, seams): use the felhom-testing skill.
• Logging: the slog logger fans out to journald (configured level) + the always-DEBUG applog.Ring (remote pulls) — English, keys-never-values, durations on outcomes; full rules in felhom.eu/documentation/runbooks/logging-conventions.md.

Live validation

Exercise the SERVER-SIDE PIPELINE a real user triggers, end-to-end. The forbidden shortcut is BYPASSING it (the F9 episode: raw guest-attach + hand-set state). Invoking the exact endpoint the UI invokes is an acceptable proxy when a browser isn't available — say which method was used. Low-level mechanism tests where the direct call IS the mechanism are exempt.

Workflow & artifacts

• Implement TASK.md / TASK-*.md specs (when placed as TASK.md or told to), then push + CHANGELOG + REPORT.md.
• RUNBOOK-*.md — an operational procedure. CC executes the steps it has access and capability for, including live validation on the demo Proxmox host (CC has root@felhom-pve SSH + the felhom-agent token). Mark a step HUMAN only when it genuinely needs physical presence, a real-world decision, or credentials CC truly lacks. Judgment still applies: confirm before irreversible ops on real customer data — demo scratch guests are fair game.