refactor(tooling): keep SERVERS in the workflows, drop it only from devnet.env

Narrows the previous commit: replacing the `for h in $SERVERS` loops with an
inline inventory query per command went further than intended. Which hosts a
command runs against is the caller's to pass, and `SERVERS` is how they pass it,
so the workflows are back to taking it from the caller and the query that fills
it stays documented where inventory.sh is introduced.

What devnet.env loses stands: no script reads SERVERS or SSH_USER, so storing
them there only created a host list to keep in step with devnet.inventory.

Author: MegaRedHand

.claude/skills/multi-server-devnet/SKILL.md

@@ -40,16 +40,19 @@ B owns `k+1..N-1`). Everything below still applies with three changes, and
 
 Nothing about the servers is hardcoded. Establish these from the operator:
 
-- The hosts: one row each in `scripts/devnet.inventory` (below), queried with
-  `scripts/inventory.sh`. There is no second host list to hold in step with it.
+- `SERVERS`: the SSH targets for the operation at hand (any count, any names),
+  one devnet each. A working set taken FROM the inventory below, not a second
+  list of hosts to keep in step with it.
 - `SSH_USER`: login user. `docker` is invoked with `sudo`.
 - Per-devnet `NODES` (validators on that server) and `SUBNETS`
   (`ATTESTATION_COMMITTEE_COUNT`); these can differ between servers.
 - A central host for Grafana + the federating Prometheus (often one of the
   servers); each server's per-host Prometheus remote-writes to it.
 
-Put the non-host values in `scripts/devnet.env` (copy `scripts/devnet.env.example`;
-gitignored) instead of retyping them: the operator-side scripts source it via
+`SERVERS`/`SSH_USER` are the caller's to pass per command: no script reads them, so
+which hosts a command runs against is decided at the call rather than stored. The
+rest goes in `scripts/devnet.env` (copy `scripts/devnet.env.example`; gitignored)
+instead of being retyped: the operator-side scripts source it via
 `scripts/devnet-env.sh`, and an env var exported in the shell still wins over the
 file. It is the one place a deployment's urls and Grafana ids live.
 
@@ -62,8 +65,8 @@ than reading it by hand:
 bash scripts/inventory.sh --tag devnet-ab --field ip        # ips, for a loop
 bash scripts/inventory.sh --tag devnet-ab --tag aggregator  # AND across tags
 bash scripts/inventory.sh --tag validator                   # derived, see below
-hosts=$(bash scripts/inventory.sh --tag devnet-ab --field name) || exit
-for h in $(echo $hosts); do ssh "$SSH_USER@$h" uptime; done  # splits in bash + zsh
+SERVERS=$(bash scripts/inventory.sh --field name) || exit   # exit 2 = typo'd tag
+SERVERS=${SERVERS//$'\n'/ }                                 # newlines -> spaces
 ```
 
 Tag conventions: a `devnet-*` tag names the chain a host's nodes belong to (two
@@ -152,20 +155,13 @@ redirect must run under sudo).
 
 ## Workflows
 
-Examples assume `SSH_USER` is set and `$h` is one host. Per server you pass its own
-`NODES`/`SUBNETS`. Keep the host query and the loop in ONE command, since a shell's
-variables don't outlive it, and `|| exit` so a typo'd tag can't leave a loop that
-does nothing and reports success:
-
-```bash
-hosts=$(bash scripts/inventory.sh --tag <devnet> --field name) || exit
-for h in $(echo $hosts); do ...; done   # $(echo ...) splits under bash and zsh
-```
+Examples assume `SSH_USER` is set and you iterate over `SERVERS`. Per server you
+pass its own `NODES`/`SUBNETS`. `for h in $SERVERS` splits under bash; zsh does not
+split parameter expansions, so there write `for h in $(echo $SERVERS)`.
 
 ### Pull the latest images on all servers
 ```bash
-hosts=$(bash scripts/inventory.sh --tag <devnet> --field name) || exit
-for h in $(echo $hosts); do ssh "$SSH_USER@$h" 'sudo docker pull ghcr.io/lambdaclass/ethlambda:devnet5'; done
+for h in $SERVERS; do ssh "$SSH_USER@$h" 'sudo docker pull ghcr.io/lambdaclass/ethlambda:devnet5'; done
 ```
 `devnet5` is the current devnet tag; it tracks the chain's leanVM/proof format,
 so it (and the other clients' tags in `references/clients.md`) move together on a

.claude/skills/multi-server-devnet/references/operations.md

@@ -6,9 +6,9 @@ SKILL.md has the workflows; this file has the depth and the failure modes.
 
 ## Topology model
 
-- SSH targets come from `scripts/devnet.inventory`, queried with
-  `scripts/inventory.sh` (any count, any names); the operator supplies `SSH_USER`
-  and `docker` runs under `sudo`. No host count, address, or spec is assumed.
+- Operator supplies SSH targets via `SERVERS` (any count, any names) and
+  `SSH_USER`; `docker` runs under `sudo`. No host count, address, or spec is
+  assumed.
 - **Each server runs its own complete devnet** — its own genesis, GENESIS_TIME,
   fork choice, and finality. No cross-server peering: every ENR is pinned to
   `127.0.0.1`, so discovery never leaves the host even though all devnets share

.claude/skills/multi-server-devnet/scripts/devnet-env.sh

@@ -64,7 +64,7 @@ devnet_load_env() {
     esac
     # Quotes, when present, DELIMIT the value, so a '#' or a trailing space inside
     # them survives. Unquoted, a `# comment` tail is dropped: it used to end up
-    # inside the value, and for METRICS_HOST that means ssh-ing to 'host # ssh'.
+    # inside the value, and for SERVERS that means sweep.sh ssh-ing to a host '#'.
     case $val in
       \"*) val=${val#\"}; val=${val%%\"*} ;;
       \'*) val=${val#\'}; val=${val%%\'*} ;;
@@ -73,8 +73,8 @@ devnet_load_env() {
     esac
     # File provides defaults only: keep an already-set value. No eval anywhere --
     # `${!key}` is bash indirect expansion, and `export` gets ONE quoted
-    # name=value word, so a multi-word value (a quoted path with a space, say)
-    # arrives whole and nothing in it is ever reparsed as shell.
+    # name=value word, so a multi-word value (SERVERS="host-a host-b") arrives
+    # whole and nothing in it is ever reparsed as shell.
     [ -n "${!key:-}" ] || export "$key=$val"
   done < "$file"
   echo "loaded deployment env from $file" >&2

.claude/skills/multi-server-devnet/scripts/devnet.env.example

@@ -4,10 +4,9 @@
 # Loaded by the operator-side scripts via devnet-env.sh; an env var already set in
 # your shell overrides the value here.
 
-# --- ssh ---------------------------------------------------------------------
-# WHICH hosts exist is devnet.inventory's business, not this file's: query it with
-# scripts/inventory.sh instead of keeping a second host list here to hold in step.
-SSH_USER=user                           # login user; docker is invoked with sudo
+# Only what a script actually reads lives here. SERVERS/SSH_USER don't: which hosts
+# a command runs against is the caller's to pass per invocation, and which hosts
+# EXIST is devnet.inventory's record, queried with scripts/inventory.sh.
 
 # --- central metrics / logs stack -------------------------------------------
 # sweep.sh reads CENTRAL_PROM_URL; the other two are args you pass to

.claude/skills/multi-server-devnet/scripts/devnet.inventory.example

@@ -12,8 +12,8 @@
 #   bash scripts/inventory.sh --tag devnet-ab --field ip        # ips, for a loop
 #   bash scripts/inventory.sh --tag devnet-ab --tag aggregator  # AND: both needed
 #   bash scripts/inventory.sh --tag validator                   # derived, see TAGS
-#   hosts=$(bash scripts/inventory.sh --tag devnet-ab --field name) || exit
-#   for h in $(echo $hosts); do ssh "$SSH_USER@$h" uptime; done  # bash + zsh
+#   SERVERS=$(bash scripts/inventory.sh --field name) || exit   # exit 2 = typo'd tag
+#   SERVERS=${SERVERS//$'\n'/ }                                 # newlines -> spaces
 #
 # FORMAT: whitespace-separated columns, aligned however you like. Blank lines and
 # lines whose first non-space character is '#' are ignored. Five columns: