fix(update): re-seed framework on version drift, not just in-command updates (#642)

`mosaic update` only re-seeded ~/.config/mosaic when the @mosaicstack/mosaic
package was upgraded *within that same command*. When the CLI is upgraded
another way — a direct `npm i -g @mosaicstack/mosaic`, or an update run where
only sibling packages were outdated — the framework files (launchers, runtime
adapters, fleet tools) silently stayed stale, so shipped fixes never activated.
Critically, the "all packages up to date" branch returned before any re-seed
could run, so a drifted-but-current host had no path to reconcile.

Add framework drift detection: compare the on-disk schema version
(~/.config/mosaic/.framework-version) against the version bundled in the
installed package (FRAMEWORK_VERSION in the bundled install.sh). `mosaic update`
now re-seeds when the mosaic package updated OR the on-disk framework is older
than bundled — including from the up-to-date branch. Detection is conservative:
if either version can't be read it reports no drift, so a missing/unreadable
version file never triggers an unexpected re-seed. `--no-reseed` still opts out.

The re-seed + unit-refresh + relaunch sequence is factored into a single local
helper shared by both the post-update and drift paths (no behavior change to the
existing path beyond also firing on drift).

New exported, unit-tested helpers in update-checker.ts:
- readInstalledFrameworkVersion / readBundledFrameworkVersion
- checkFrameworkDrift -> { drifted, installed, bundled }

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/mosaic/framework/tools/git/pr-merge.sh

@@ -128,8 +128,8 @@ PY
 merge_gitea_with_api() {
     local host="$1" api_url token basic_auth body_file raw_code payload
     api_url="https://${host}/api/v1/repos/${OWNER}/${REPO}/pulls/${PR_NUMBER}/merge"
-    mkdir -p "${AGENT_WORK_ROOT:-/home/hermes/agent-work}"
-    body_file=$(mktemp "${AGENT_WORK_ROOT:-/home/hermes/agent-work}/pr-merge-api-response.XXXXXX")
+    mkdir -p "${AGENT_WORK_ROOT:-${HOME:-/tmp}/mosaic/agent-work}"
+    body_file=$(mktemp "${AGENT_WORK_ROOT:-${HOME:-/tmp}/mosaic/agent-work}/pr-merge-api-response.XXXXXX")
     payload='{"Do":"squash"}'
 
     token=$(get_gitea_token "$host" || true)
@@ -214,8 +214,8 @@ case "$PLATFORM" in
         TEA_LOGIN="$(get_gitea_login_for_host "$HOST" || true)"
 
         if [[ -n "$TEA_LOGIN" ]]; then
-            mkdir -p "${AGENT_WORK_ROOT:-/home/hermes/agent-work}"
-            TEA_ERROR_FILE=$(mktemp "${AGENT_WORK_ROOT:-/home/hermes/agent-work}/pr-merge-tea-error.XXXXXX")
+            mkdir -p "${AGENT_WORK_ROOT:-${HOME:-/tmp}/mosaic/agent-work}"
+            TEA_ERROR_FILE=$(mktemp "${AGENT_WORK_ROOT:-${HOME:-/tmp}/mosaic/agent-work}/pr-merge-tea-error.XXXXXX")
             if tea pr merge "$PR_NUMBER" --style squash --repo "$OWNER/$REPO" --login "$TEA_LOGIN" 2> "$TEA_ERROR_FILE"; then
                 rm -f "$TEA_ERROR_FILE"
             elif is_known_tea_empty_identity_failure "$TEA_ERROR_FILE"; then

packages/mosaic/framework/tools/git/test-pr-merge-gitea-empty-uid.sh

@@ -4,7 +4,7 @@
 set -euo pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-WORK_ROOT="${AGENT_WORK_ROOT:-/home/hermes/agent-work}"
+WORK_ROOT="${AGENT_WORK_ROOT:-${HOME:-/tmp}/mosaic/agent-work}"
 SANDBOX="$WORK_ROOT/pr-merge-empty-uid-test-$$"
 MOCK_BIN="$SANDBOX/bin"
 REPO_DIR="$SANDBOX/repo"

packages/mosaic/framework/tools/tmux/agent-send.sh

@@ -12,6 +12,10 @@
 #   ambiguity about lanes or origin. Recipients replying should FLIP the
 #   preamble: [<dst> -> <src>] ... (this tool sends; it does not auto-reply).
 #
+#   Optionally tags the message with a TRIAGE CLASS (see -C / --class) so a
+#   comms daemon can route it (deliver-to-agent vs log-and-drop) from an exact
+#   field instead of re-deriving intent from the body.
+#
 # WHY A WRAPPER
 #   Reliable submission into an interactive REPL (Claude Code / Codex) is fiddly:
 #   a trailing Enter is often swallowed and the message sits as an unsubmitted
@@ -26,6 +30,7 @@
 #   agent-send.sh [-L socket] -s <dst_session> -m "message"                 # local target
 #   agent-send.sh [-L socket] -H user@host -s <dst_session> -m "message"    # remote target
 #   agent-send.sh [-L socket] -H user@host -n <dst_hostname> -s <sess> -f msg.txt
+#   agent-send.sh -s mos-claude --class terminal-log -m "ACK — received"
 #   echo "msg" | agent-send.sh [-L socket] -H user@host -s <dst_session>
 #
 # OPTIONS
@@ -36,27 +41,61 @@
 #                   Default: local hostname, or (remote) resolved via one ssh.
 #   -m MESSAGE      message text (single- or multi-line)
 #   -f FILE         read message from FILE instead of -m
+#   -C CLASS        triage class for a comms daemon. One of:
+#                     terminal-log  log-only; never needs the agent's attention
+#                     actionable    carries a decision/blocker/gate — deliver
+#                     human         from a human operator — deliver
+#                     reaction      an emoji/ack reaction
+#                   Long form: --class CLASS (or --class=CLASS). When SET, the
+#                   preamble carries a ` class=<CLASS>` token INSIDE the bracket:
+#                       [<src> -> <dst> class=terminal-log] <message>
+#                   When OMITTED, NO token is emitted and the preamble is
+#                   byte-for-byte identical to the classic format. Consumers MUST
+#                   treat an absent class as 'actionable' (fail-safe: agent sees it).
 #   -S SRC_LABEL    override source label "<host>:<session>" (default: auto)
 #   -r N            Enter-flush attempts passed through (default 2)
 #   -v              verbose: print pane tail after delivery
 #   -h              help
 #
+# PREAMBLE GRAMMAR  (for consumers / daemons mirroring this producer)
+#   ^\[(\S+) -> (\S+?)(?: class=(terminal-log|actionable|human|reaction))?\] (.*)$
+#     group 1 = src label   group 2 = dst host:session
+#     group 3 = class (absent => actionable)   group 4 = message body
+#
 # EXIT CODES  (passed through from send-message.sh)
 #   0 delivered/queued · 1 target not found · 2 still draft · 3 usage error
 set -uo pipefail
 
 SELF_DIR=$(cd -- "$(dirname -- "$0")" && pwd)
-SENDER="$SELF_DIR/send-message.sh"
+# Sender is overridable via env purely for testing (inject a capture stub). The
+# default is the canonical send-message.sh beside this script; production callers
+# never set AGENT_SEND_SENDER, so behavior is unchanged.
+SENDER="${AGENT_SEND_SENDER:-$SELF_DIR/send-message.sh}"
+
+# Translate the long option --class[=value] into "-C value" so getopts (which is
+# short-option-only) can parse it. Every other argument passes through untouched,
+# so callers that never use --class hit the exact original getopts path.
+args=()
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --class)   [ $# -ge 2 ] || { echo "ERROR: --class requires a value" >&2; exit 3; }
+               args+=(-C "$2"); shift 2 ;;
+    --class=*) args+=(-C "${1#*=}"); shift ;;
+    *)         args+=("$1"); shift ;;
+  esac
+done
+set -- ${args[@]+"${args[@]}"}
 
 DST_SESSION=""; SSH_TARGET=""; DST_HOST=""; MSG=""; FILE=""; SOCKET_NAME=""
-SRC_LABEL=""; RETRIES=2; VERBOSE=0
-usage() { sed -n '2,44p' "$0"; exit "${1:-3}"; }
+SRC_LABEL=""; RETRIES=2; VERBOSE=0; CLASS=""
+usage() { sed -n '2,/^set -uo pipefail/{/^set -uo pipefail/d;p}' "$0"; exit "${1:-3}"; }
 
-while getopts "L:s:H:n:m:f:S:r:vh" o; do
+while getopts "L:s:H:n:m:f:S:r:C:vh" o; do
   case "$o" in
     L) SOCKET_NAME=$OPTARG ;;
     s) DST_SESSION=$OPTARG ;; H) SSH_TARGET=$OPTARG ;; n) DST_HOST=$OPTARG ;;
     m) MSG=$OPTARG ;; f) FILE=$OPTARG ;; S) SRC_LABEL=$OPTARG ;;
+    C) CLASS=$OPTARG ;;
     r) RETRIES=$OPTARG ;; v) VERBOSE=1 ;; h) usage 0 ;; *) usage 3 ;;
   esac
 done
@@ -64,6 +103,17 @@ done
 [ -n "$DST_SESSION" ] || { echo "ERROR: -s DST_SESSION is required" >&2; usage 3; }
 [ -x "$SENDER" ] || { echo "ERROR: send-message.sh not found beside this script" >&2; exit 3; }
 
+# Validate the triage class only when one was given. An absent class emits NO
+# token (preamble byte-identical to the classic format); the consumer defaults
+# absent => actionable.
+CLASS_TOKEN=""
+if [ -n "$CLASS" ]; then
+  case "$CLASS" in
+    terminal-log|actionable|human|reaction) CLASS_TOKEN=" class=${CLASS}" ;;
+    *) echo "ERROR: invalid --class '$CLASS' (allowed: terminal-log, actionable, human, reaction)" >&2; exit 3 ;;
+  esac
+fi
+
 # Message body from -f / -m / stdin.
 if   [ -n "$FILE" ]; then [ -r "$FILE" ] || { echo "ERROR: cannot read $FILE" >&2; exit 3; }; MSG=$(cat -- "$FILE")
 elif [ -z "$MSG" ] && [ ! -t 0 ]; then MSG=$(cat)
@@ -90,7 +140,7 @@ if [ -z "$DST_HOST" ]; then
   fi
 fi
 
-PREAMBLE="[${SRC_LABEL} -> ${DST_HOST}:${DST_SESSION}]"
+PREAMBLE="[${SRC_LABEL} -> ${DST_HOST}:${DST_SESSION}${CLASS_TOKEN}]"
 FULL="${PREAMBLE} ${MSG}"
 B64=$(printf '%s' "$FULL" | base64 -w0)
 

packages/mosaic/framework/tools/tmux/agent-send.test.sh

@@ -0,0 +1,97 @@
+#!/usr/bin/env bash
+# agent-send.test.sh — regression + grammar lock for agent-send.sh --class.
+#
+# Strategy: inject a capture stub via AGENT_SEND_SENDER that decodes the -b
+# base64 payload and prints the FULL message (preamble + body) so we can assert
+# the exact bytes on the wire. Local path only (no ssh), -n pins the dst host so
+# the preamble is deterministic across machines.
+#
+# Guarantees locked here:
+#   1. REGRESSION BAR — no --class => preamble byte-for-byte identical to classic.
+#   2. --class <c> => ` class=<c>` token emitted inside the bracket.
+#   3. --class=<c> (equals form) parses identically to the space form.
+#   4. -C <c> short form parses identically.
+#   5. invalid class => exit 3, nothing sent.
+#   6. --class with no value => exit 3.
+#   7. the documented consumer regex parses producer output for every class.
+set -uo pipefail
+
+HERE=$(cd -- "$(dirname -- "$0")" && pwd)
+TOOL="$HERE/agent-send.sh"
+
+# Capture stub: stands in for send-message.sh. Decodes -b and prints the payload.
+STUB=$(mktemp)
+trap 'rm -f "$STUB"' EXIT
+cat >"$STUB" <<'STUB_EOF'
+#!/usr/bin/env bash
+set -uo pipefail
+b64=""
+while getopts "t:b:r:v" o; do case "$o" in b) b64=$OPTARG ;; *) : ;; esac; done
+printf '%s' "$b64" | base64 -d
+STUB_EOF
+chmod +x "$STUB"
+
+PASS=0; FAIL=0
+ok()   { PASS=$((PASS+1)); printf 'ok   %s\n' "$1"; }
+no()   { FAIL=$((FAIL+1)); printf 'FAIL %s\n   %s\n' "$1" "$2"; }
+
+# Run the tool with the stub injected; echoes captured payload on stdout.
+run() { AGENT_SEND_SENDER="$STUB" bash "$TOOL" -S a:src -n dsthost "$@"; }
+
+# Documented consumer grammar — the daemon will mirror exactly this.
+GRAMMAR='^\[(\S+) -> (\S+) class=(terminal-log|actionable|human|reaction)\] (.*)$'
+GRAMMAR_NOCLASS='^\[(\S+) -> (\S+)\] (.*)$'
+
+# 1. REGRESSION BAR: classic preamble, byte-for-byte.
+got=$(run -s mos -m "hello world")
+want='[a:src -> dsthost:mos] hello world'
+[ "$got" = "$want" ] && ok "regression: no --class is byte-identical" \
+  || no "regression: no --class is byte-identical" "got=[$got] want=[$want]"
+
+# 2. --class space form emits the token.
+got=$(run -s mos --class terminal-log -m "ACK")
+want='[a:src -> dsthost:mos class=terminal-log] ACK'
+[ "$got" = "$want" ] && ok "--class terminal-log emits token" \
+  || no "--class terminal-log emits token" "got=[$got] want=[$want]"
+
+# 3. --class=value equals form.
+got=$(run -s mos --class=actionable -m "decide X")
+want='[a:src -> dsthost:mos class=actionable] decide X'
+[ "$got" = "$want" ] && ok "--class=actionable (equals form)" \
+  || no "--class=actionable (equals form)" "got=[$got] want=[$want]"
+
+# 4. -C short form.
+got=$(run -s mos -C human -m "from a person")
+want='[a:src -> dsthost:mos class=human] from a person'
+[ "$got" = "$want" ] && ok "-C human (short form)" \
+  || no "-C human (short form)" "got=[$got] want=[$want]"
+
+# 5. invalid class => exit 3, no send.
+if out=$(run -s mos --class bogus -m "x" 2>/dev/null); then
+  no "invalid class rejected" "expected non-zero exit, got 0 (out=[$out])"
+else
+  rc=$?
+  [ "$rc" = 3 ] && [ -z "$out" ] && ok "invalid class => exit 3, nothing sent" \
+    || no "invalid class => exit 3, nothing sent" "rc=$rc out=[$out]"
+fi
+
+# 6. --class with no value => exit 3.
+if run -s mos -m "x" --class 2>/dev/null; then
+  no "--class with no value rejected" "expected non-zero exit, got 0"
+else
+  [ "$?" = 3 ] && ok "--class with no value => exit 3" || no "--class with no value => exit 3" "wrong rc"
+fi
+
+# 7. consumer grammar parses every class + classic line.
+for c in terminal-log actionable human reaction; do
+  line=$(run -s mos --class "$c" -m "body $c")
+  [[ "$line" =~ $GRAMMAR ]] && [ "${BASH_REMATCH[3]}" = "$c" ] && [ "${BASH_REMATCH[4]}" = "body $c" ] \
+    && ok "grammar parses class=$c" || no "grammar parses class=$c" "line=[$line]"
+done
+classic=$(run -s mos -m "plain body")
+[[ "$classic" =~ $GRAMMAR_NOCLASS ]] && [ "${BASH_REMATCH[3]}" = "plain body" ] \
+  && ok "grammar (no-class) parses classic line" || no "grammar (no-class) parses classic line" "line=[$classic]"
+
+echo "---"
+echo "PASS=$PASS FAIL=$FAIL"
+[ "$FAIL" -eq 0 ]

packages/mosaic/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@mosaicstack/mosaic",
-  "version": "0.0.40",
+  "version": "0.0.41",
   "repository": {
     "type": "git",
     "url": "https://git.mosaicstack.dev/mosaicstack/stack.git",

packages/mosaic/src/cli.ts

@@ -30,6 +30,7 @@ import {
   refreshActiveFleetUnits,
   readRosterAgentNames,
   buildRelaunchCommands,
+  checkFrameworkDrift,
   FRAMEWORK_RESEED_PACKAGE,
 } from './runtime/update-checker.js';
 import { runWizard } from './wizard.js';
@@ -418,6 +419,48 @@ program
     // checkForAllUpdates imported statically above
     const { execSync } = await import('node:child_process');
 
+    // Re-seed the framework from the freshly-installed package, propagate shipped
+    // systemd unit fixes to the active units, and (opt-in) relaunch durable
+    // agents. Shared by the "packages updated" and the "framework drift" paths.
+    const reseedFramework = (reason: string): void => {
+      console.log(reason);
+      const reseed = runFrameworkReseed();
+      if (!reseed.ok) {
+        console.error(
+          `\n⚠ Framework re-seed skipped: ${reseed.reason ?? 'unknown'}.\n` +
+            '  Activate manually: bash "$(npm root -g)/@mosaicstack/mosaic/framework/install.sh" ' +
+            '(MOSAIC_SYNC_ONLY=1 MOSAIC_INSTALL_MODE=keep)',
+        );
+        return;
+      }
+      console.log('✔ Framework re-seeded.');
+      // Propagate shipped systemd unit fixes to the ACTIVE units (re-seed only
+      // touches ~/.config/mosaic/systemd/user; systemd runs ~/.config/systemd/user).
+      const units = refreshActiveFleetUnits();
+      if (units.refreshed.length > 0) {
+        console.log(`✔ Refreshed ${units.refreshed.length} active systemd unit(s).`);
+      }
+      const agents = readRosterAgentNames();
+      if (agents.length === 0) return;
+      if (opts.relaunch) {
+        console.log(`\nRelaunching ${agents.length} fleet agent(s) to pick up the new runtime…`);
+        for (const restart of buildRelaunchCommands(agents)) {
+          try {
+            execSync(restart.join(' '), { stdio: 'inherit', timeout: 30_000 });
+          } catch {
+            console.error(`  ⚠ failed to restart agent — run: ${restart.join(' ')}`);
+          }
+        }
+        console.log('✔ Agents relaunched.');
+      } else {
+        console.log(
+          `\nℹ ${agents.length} fleet agent(s) are still running the previous runtime. ` +
+            'Restart them to activate the update:\n    mosaic update --relaunch   ' +
+            '(or: mosaic fleet restart <agent>)',
+        );
+      }
+    };
+
     console.log('Checking for updates…');
     const results = checkForAllUpdates({ skipCache: true });
 
@@ -432,6 +475,18 @@ program
         process.exit(1);
       }
       console.log('\n✔ All packages up to date.');
+      // #642: the CLI may have been upgraded outside `mosaic update` (e.g. a
+      // direct `npm i -g`), leaving the framework files stale even though no
+      // package is reported outdated. Detect that via the framework version and
+      // re-seed so shipped launcher/runtime fixes still activate.
+      const drift = checkFrameworkDrift();
+      if (drift.drifted && opts.reseed !== false) {
+        reseedFramework(
+          `\nFramework drift detected (on-disk v${drift.installed} < bundled v${drift.bundled}) — ` +
+            'the CLI was updated outside `mosaic update`. Re-seeding framework files into ' +
+            '~/.config/mosaic (data-safe; keeps your edits)…',
+        );
+      }
       return;
     }
 
@@ -456,52 +511,17 @@ program
     // F3-m3 / R13: the CLI is updated, but the framework files in
     // ~/.config/mosaic/ are still the previous version. Re-seed them from the
     // freshly-installed package so shipped launcher/runtime changes ACTIVATE.
-    // Only when the framework-bearing package itself updated.
+    // Re-seed when the framework-bearing package itself updated OR the on-disk
+    // framework is older than the freshly-installed one (#642 — e.g. only
+    // sibling packages were outdated but the CLI was already ahead).
     const mosaicUpdated = outdated.some(
       (r: { package: string }) => r.package === FRAMEWORK_RESEED_PACKAGE,
     );
-    if (mosaicUpdated && opts.reseed !== false) {
-      console.log(
+    const drift = checkFrameworkDrift();
+    if ((mosaicUpdated || drift.drifted) && opts.reseed !== false) {
+      reseedFramework(
         '\nRe-seeding framework files into ~/.config/mosaic (data-safe; keeps your edits)…',
       );
-      const reseed = runFrameworkReseed();
-      if (reseed.ok) {
-        console.log('✔ Framework re-seeded.');
-        // Propagate shipped systemd unit fixes to the ACTIVE units (re-seed only
-        // touches ~/.config/mosaic/systemd/user; systemd runs ~/.config/systemd/user).
-        const units = refreshActiveFleetUnits();
-        if (units.refreshed.length > 0) {
-          console.log(`✔ Refreshed ${units.refreshed.length} active systemd unit(s).`);
-        }
-        const agents = readRosterAgentNames();
-        if (agents.length > 0) {
-          if (opts.relaunch) {
-            console.log(
-              `\nRelaunching ${agents.length} fleet agent(s) to pick up the new runtime…`,
-            );
-            for (const restart of buildRelaunchCommands(agents)) {
-              try {
-                execSync(restart.join(' '), { stdio: 'inherit', timeout: 30_000 });
-              } catch {
-                console.error(`  ⚠ failed to restart agent — run: ${restart.join(' ')}`);
-              }
-            }
-            console.log('✔ Agents relaunched.');
-          } else {
-            console.log(
-              `\nℹ ${agents.length} fleet agent(s) are still running the previous runtime. ` +
-                'Restart them to activate the update:\n    mosaic update --relaunch   ' +
-                '(or: mosaic fleet restart <agent>)',
-            );
-          }
-        }
-      } else {
-        console.error(
-          `\n⚠ Framework re-seed skipped: ${reseed.reason ?? 'unknown'}.\n` +
-            '  Activate manually: bash "$(npm root -g)/@mosaicstack/mosaic/framework/install.sh" ' +
-            '(MOSAIC_SYNC_ONLY=1 MOSAIC_INSTALL_MODE=keep)',
-        );
-      }
     }
   });
 

packages/mosaic/src/runtime/update-checker.reseed.spec.ts

@@ -8,6 +8,9 @@ import {
   readRosterAgentNames,
   runFrameworkReseed,
   refreshActiveFleetUnits,
+  readInstalledFrameworkVersion,
+  readBundledFrameworkVersion,
+  checkFrameworkDrift,
 } from './update-checker.js';
 import { existsSync, readFileSync } from 'node:fs';
 
@@ -123,3 +126,73 @@ describe('refreshActiveFleetUnits', () => {
     expect(existsSync(join(configHome, 'systemd', 'user', 'mosaic-agent@.service'))).toBe(false);
   });
 });
+
+/**
+ * #642: re-seed when the on-disk framework is older than the bundled one even
+ * if no package is reported outdated (CLI upgraded outside `mosaic update`).
+ */
+describe('framework drift detection', () => {
+  let home: string; // stand-in for ~/.config/mosaic
+  let fw: string; // stand-in for the bundled framework root
+
+  beforeEach(() => {
+    const root = mkdtempSync(join(tmpdir(), 'mosaic-drift-'));
+    home = join(root, 'mosaic');
+    fw = join(root, 'framework');
+    mkdirSync(home, { recursive: true });
+    mkdirSync(fw, { recursive: true });
+  });
+  afterEach(() => {
+    rmSync(join(home, '..'), { recursive: true, force: true });
+  });
+
+  const writeInstalled = (v: string) => writeFileSync(join(home, '.framework-version'), v);
+  const writeBundled = (v: string) =>
+    writeFileSync(join(fw, 'install.sh'), `#!/usr/bin/env bash\nFRAMEWORK_VERSION=${v}\n`);
+
+  describe('readInstalledFrameworkVersion', () => {
+    it('returns undefined when the version file is absent', () => {
+      expect(readInstalledFrameworkVersion(home)).toBeUndefined();
+    });
+    it('parses the integer (tolerating surrounding whitespace)', () => {
+      writeInstalled('  3\n');
+      expect(readInstalledFrameworkVersion(home)).toBe(3);
+    });
+    it('returns undefined for non-numeric content', () => {
+      writeInstalled('not-a-number\n');
+      expect(readInstalledFrameworkVersion(home)).toBeUndefined();
+    });
+  });
+
+  describe('readBundledFrameworkVersion', () => {
+    it('returns undefined when install.sh is absent', () => {
+      expect(readBundledFrameworkVersion(fw)).toBeUndefined();
+    });
+    it('parses FRAMEWORK_VERSION=<n> from install.sh', () => {
+      writeBundled('4');
+      expect(readBundledFrameworkVersion(fw)).toBe(4);
+    });
+  });
+
+  describe('checkFrameworkDrift', () => {
+    it('reports drift when on-disk is older than bundled', () => {
+      writeInstalled('3');
+      writeBundled('4');
+      expect(checkFrameworkDrift(home, fw)).toEqual({ drifted: true, installed: 3, bundled: 4 });
+    });
+    it('no drift when versions match', () => {
+      writeInstalled('4');
+      writeBundled('4');
+      expect(checkFrameworkDrift(home, fw)).toMatchObject({ drifted: false });
+    });
+    it('no drift when on-disk is newer than bundled', () => {
+      writeInstalled('5');
+      writeBundled('4');
+      expect(checkFrameworkDrift(home, fw)).toMatchObject({ drifted: false });
+    });
+    it('no drift (conservative) when a version cannot be read', () => {
+      writeBundled('4'); // installed version file missing
+      expect(checkFrameworkDrift(home, fw)).toMatchObject({ drifted: false, bundled: 4 });
+    });
+  });
+});

packages/mosaic/src/runtime/update-checker.ts

@@ -521,6 +521,75 @@ export function runFrameworkReseed(
   }
 }
 
+// ─── Framework drift detection (#642) ────────────────────────────────────────
+//
+// `mosaic update` only re-seeds the framework when the @mosaicstack/mosaic
+// package itself is upgraded *within that command*. When the CLI is upgraded
+// some OTHER way — a direct `npm i -g @mosaicstack/mosaic`, or an upgrade run
+// where only sibling packages were outdated — the framework files in
+// ~/.config/mosaic stay stale and shipped launcher/runtime fixes never
+// activate. Comparing the on-disk framework schema version against the version
+// bundled in the installed package detects exactly that situation.
+
+/** Read the framework schema version recorded on disk (~/.config/mosaic/.framework-version). */
+export function readInstalledFrameworkVersion(
+  mosaicHome = join(homedir(), '.config', 'mosaic'),
+): number | undefined {
+  const vf = join(mosaicHome, '.framework-version');
+  if (!existsSync(vf)) return undefined;
+  try {
+    const n = parseInt(readFileSync(vf, 'utf-8').trim(), 10);
+    return Number.isFinite(n) ? n : undefined;
+  } catch {
+    return undefined;
+  }
+}
+
+/**
+ * Read the framework schema version shipped in the installed package by parsing
+ * `FRAMEWORK_VERSION=<n>` out of the bundled install.sh (the authoritative
+ * source the installer writes to .framework-version).
+ */
+export function readBundledFrameworkVersion(
+  frameworkRoot = resolveBundledFrameworkRoot(),
+): number | undefined {
+  const installer = join(frameworkRoot, 'install.sh');
+  if (!existsSync(installer)) return undefined;
+  try {
+    const m = readFileSync(installer, 'utf-8').match(/^\s*FRAMEWORK_VERSION=(\d+)/m);
+    const raw = m?.[1];
+    if (!raw) return undefined;
+    const n = parseInt(raw, 10);
+    return Number.isFinite(n) ? n : undefined;
+  } catch {
+    return undefined;
+  }
+}
+
+export interface FrameworkDrift {
+  /** True only when both versions are known AND the on-disk one is older. */
+  drifted: boolean;
+  installed?: number;
+  bundled?: number;
+}
+
+/**
+ * Detect whether the on-disk framework is older than the framework bundled in
+ * the installed CLI (#642). Conservative: if either version can't be read the
+ * result is no-drift, so a missing/unreadable version file never triggers an
+ * unexpected re-seed.
+ */
+export function checkFrameworkDrift(
+  mosaicHome = join(homedir(), '.config', 'mosaic'),
+  frameworkRoot = resolveBundledFrameworkRoot(),
+): FrameworkDrift {
+  const installed = readInstalledFrameworkVersion(mosaicHome);
+  const bundled = readBundledFrameworkVersion(frameworkRoot);
+  const drifted =
+    typeof installed === 'number' && typeof bundled === 'number' && installed < bundled;
+  return { drifted, installed, bundled };
+}
+
 /**
  * Best-effort parse of the fleet roster for agent names (used to relaunch
  * durable agents after a re-seed). Returns [] when no roster exists.