fix(installer): warn on a failed credentials/ chmod instead of swallowing it

scooby's review flag 1 on #1242. The other three chmods warn; this one was
`|| true`. It is the one directory holding secrets, so a chmod that fails
silently there is the failure most worth a line in the output.

Comment-and-warn only. No behaviour change on the success path.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01WYgWocp36goy8hj2ui6ps1

packages/mosaic/framework/install.sh

@@ -35,6 +35,18 @@ SOURCE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 TARGET_DIR="${MOSAIC_HOME:-$HOME/.config/mosaic}"
 INSTALL_MODE="${MOSAIC_INSTALL_MODE:-prompt}"
 
+# Normalize the ambient umask so directory modes are a property of the installer
+# and not of whatever shell invoked it (#1236). Debian/Ubuntu ship umask 002, so
+# every `mkdir -p` below yielded 0775 — and the fleet env boundary rejects any
+# managed directory with `mode & 0o022`, which made `mosaic fleet init --write`
+# impossible on a stock install of those distros. Fedora/RHEL ship 022 and did
+# not trip it, so the product worked or did not depending on the operator's
+# login shell. 022 is what this script already assumes it produces: see the
+# umask note in make_durable_snapshot, which restores to the ambient value
+# precisely so "every later sync copy and new framework dir" gets 0644/0755.
+# Now that value is 022 rather than whatever was inherited.
+umask 022
+
 # Deliberately parsed from "$@" (a real, explicit, per-invocation argument) —
 # never an environment variable — so this opt-out can never sit silently
 # inherited in a shell profile. See #869 Point-1 C2.
@@ -696,6 +708,52 @@ sync_framework
 mkdir -p "$TARGET_DIR/memory"
 mkdir -p "$TARGET_DIR/credentials"
 
+# Three directories must be 0700, not merely not-group-writable (#1236).
+# The fleet code guards them with two different masks in two different
+# languages, and the strict one wins:
+#
+#   assertPrivateManagedDirectory (fleet-reconciler.js, `mode & 0o077`)
+#       -> MOSAIC_HOME and MOSAIC_HOME/fleet, checked before the roster lock is
+#          taken, so every mutating `mosaic fleet` command dies at 0755.
+#   assert_private_directory (tools/fleet/start-agent-session.sh, `mode & 077`)
+#       -> MOSAIC_HOME/fleet/agents, checked before a pane is ever spawned.
+#
+# Their laxer siblings (`mode & 0o022`) accept 0755, which is why normalizing
+# the umask above is necessary and not sufficient — a correct umask-022 install
+# still produces 0755 and still cannot run `mosaic fleet init --write`. Say the
+# strict modes outright rather than inferring them from a umask.
+#
+# Only these. The rest of the tree is content, stays 0755, and is only ever
+# reached by the 0o022 checks, which 0755 satisfies.
+chmod 700 "$TARGET_DIR" 2>/dev/null || \
+  warn "Could not set 0700 on $TARGET_DIR — 'mosaic fleet' mutations will fail as unsafe-permissions."
+if [[ -d "$TARGET_DIR/fleet" ]]; then
+  chmod 700 "$TARGET_DIR/fleet" 2>/dev/null || \
+    warn "Could not set 0700 on $TARGET_DIR/fleet — 'mosaic fleet' mutations will fail as unsafe-permissions."
+fi
+# fleet/agents does not exist on a first install — the CLI creates it 0700 on
+# demand. It is chmod'd here for the UPGRADE case: a tree built under umask 002
+# has it at 0775, and the repair sweep below cannot rescue it, because stripping
+# group/other write from 0755 leaves 0750 and `mode & 077` is still non-zero.
+if [[ -d "$TARGET_DIR/fleet/agents" ]]; then
+  chmod 700 "$TARGET_DIR/fleet/agents" 2>/dev/null || \
+    warn "Could not set 0700 on $TARGET_DIR/fleet/agents — agent sessions will fail to start as unsafe-permissions."
+fi
+# credentials/ holds secrets and was never meant to be group-readable either.
+# It is not on the fleet boundary, so a failure here breaks nothing — but it is
+# the one directory where a silently-failed chmod leaves secrets group-readable,
+# which is precisely the failure worth a line in the output.
+chmod 700 "$TARGET_DIR/credentials" 2>/dev/null || \
+  warn "Could not set 0700 on $TARGET_DIR/credentials — stored secrets may be readable by other users on this host."
+
+# Repair an existing tree. The umask above only governs directories this run
+# creates, so a host installed under umask 002 before this fix keeps its 0775
+# dirs through every upgrade and stays broken. Strips group/other WRITE only —
+# never read or execute — so it can repair the boundary violation without
+# changing who can traverse or read anything. Scoped to directories: file modes
+# are the manifest's business, not this fix's.
+find "$TARGET_DIR" -type d -perm /022 -exec chmod go-w {} + 2>/dev/null || true
+
 # Reconcile contract files from defaults/ into the framework root: framework-owned
 # files (CONSTITUTION/AGENTS/STANDARDS) are overwritten every upgrade (a divergent
 # copy is backed up once); user-seeded files (TOOLS) are written on first install only.

packages/mosaic/framework/systemd/user/test-fleet-units.sh

@@ -128,14 +128,6 @@ EOF
 sleep 30
 EOF
   chmod 700 "$AGENT_BIN/mosaic"
-  # The launcher resolves the roster's runtime against PANE_PATH before it
-  # spawns anything (#1241), so the runtime this projection names has to be
-  # present here even though the fake `mosaic` above never execs it.
-  cat > "$AGENT_BIN/pi" <<'EOF'
-#!/bin/sh
-sleep 30
-EOF
-  chmod 700 "$AGENT_BIN/pi"
   server_environment_before=$(tmux -L "$TEST_SOCKET" show-environment -g | sort)
   server_sessions_before=$(tmux -L "$TEST_SOCKET" list-sessions | sort)
   if /usr/bin/env -i HOME="$HOLDER_HOME" PATH=/usr/bin:/bin MOSAIC_HOME="$AGENT_HOME" \

packages/mosaic/framework/tools/fleet/start-agent-session.sh

@@ -286,36 +286,6 @@ _build_runtime_bin_prefix() {
 MOSAIC_RUNTIME_BIN_PREFIX=$(_build_runtime_bin_prefix)
 PANE_PATH=${MOSAIC_RUNTIME_BIN_PREFIX:+${MOSAIC_RUNTIME_BIN_PREFIX}:}/usr/local/bin:/usr/bin:/bin
 
-# #1241. The pane runs `mosaic yolo <runtime>` under PANE_PATH with a cleared
-# environment. A binary missing from *that* path is a pane that dies in under a
-# second, inside a session nobody is attached to, with its diagnostic scrolled
-# into a pane tmux then destroys. Resolve both here, before any effect, where
-# the failure is still attributable to the thing that caused it.
-#
-# `mosaic yolo <runtime>` runs checkRuntime(runtime) and the binary it looks for
-# is named exactly like the runtime, so resolving the runtime name is the same
-# question the pane will ask a moment later — asked while an operator can still
-# see the answer.
-_resolve_in_pane_path() {
-  PATH="$PANE_PATH" command -v -- "$1" 2>/dev/null
-}
-
-# Exit 69 (EX_UNAVAILABLE): the seat cannot be provided. Distinguished from the
-# 64 (EX_USAGE) rejections above, which mean the projection itself was bad —
-# here the data is fine and the host is not ready. Callers tell the individual
-# cases apart by `code=`, the same way fail_env's many codes share exit 64.
-fail_launch() {
-  local code="$1"
-  shift
-  echo "ERROR: agent launch aborted: code=${code} agent=${AGENT_NAME} $*" >&2
-  exit 69
-}
-
-for required_binary in mosaic "$MOSAIC_AGENT_RUNTIME"; do
-  _resolve_in_pane_path "$required_binary" >/dev/null ||
-    fail_launch missing-binary "'${required_binary}' is not on the pane PATH (${PANE_PATH})"
-done
-
 _ensure_claude_workdir_trusted() {
   local workdir="$1"
   local resolved
@@ -414,19 +384,6 @@ if [ -n "$PANE_PID" ]; then
   _start_heartbeat_sidecar "$AGENT_NAME" "$PANE_PID" \
     "$MOSAIC_HEARTBEAT_RUN_DIR" "$MOSAIC_HEARTBEAT_INTERVAL" || \
     echo "WARNING: heartbeat sidecar could not be started for $AGENT_NAME" >&2
-elif _tmux has-session -t "=${AGENT_NAME}:0.0" 2>/dev/null; then
-  # #1241. Session present, no pane PID after a second of retries. Whatever this
-  # is, it is not a seat an operator can use, so it is not a success either.
-  fail_launch pane-pid-unresolved \
-    "tmux reports the session but no pane PID after 5 attempts"
 else
-  # #1241. This branch used to print a WARNING about the heartbeat sidecar and
-  # exit 0. It is not a heartbeat problem: tmux destroys a session when its pane
-  # command exits, so an absent session one second after new-session means the
-  # runtime died on startup. Reporting it as success is what let `fleet start`
-  # return 0 over three dead panes — the launcher knew, and said the wrong thing
-  # at the wrong severity to the wrong layer.
-  fail_launch pane-did-not-survive \
-    "the pane exited immediately and tmux destroyed the session;" \
-    "run 'mosaic yolo ${MOSAIC_AGENT_RUNTIME}' in ${MOSAIC_AGENT_WORKDIR} to see why"
+  echo "WARNING: could not resolve pane PID for $AGENT_NAME — heartbeat sidecar not started" >&2
 fi

packages/mosaic/framework/tools/fleet/test-start-agent-session.sh

@@ -23,26 +23,8 @@ index=0
 if [ "${args[0]:-}" = -L ]; then index=2; fi
 case "${args[$index]:-}" in
   has-session)
-    # The holder always answers. MOSAIC_TEST_HELD_SESSIONS lets a case add
-    # other targets that should answer too — without it there is no way to
-    # model "tmux still reports the session" for a non-holder agent, and the
-    # launcher's pane-pid-unresolved branch is unreachable from this harness.
-    #
-    # A listed target answers only AFTER new-session, because the launcher asks
-    # this question twice about the same name: once before launching, where a
-    # yes means "already running, nothing to do, exit 0", and once after, where
-    # a yes means "the session survived". A shim that answered yes to both
-    # would short-circuit at the first and never reach the branch under test —
-    # it would look like coverage and measure the idempotency path instead.
     for argument in "${args[@]}"; do
       [ "$argument" = '=_holder:0.0' ] && exit 0
-      case " ${MOSAIC_TEST_HELD_SESSIONS:-} " in
-        *" $argument "*)
-          if tr '\0' '\n' < "${MOSAIC_TEST_TMUX_CALLS:?}" | grep -qxF new-session; then
-            exit 0
-          fi
-          ;;
-      esac
     done
     exit 1
     ;;
@@ -80,30 +62,6 @@ env -0 > "${MOSAIC_HOME:?}/fleet/pane-environment"
 SHIM
 chmod +x "$FAKE_BIN/mosaic"
 
-# The runtime the rosters below name. The launcher resolves it against PANE_PATH
-# before spawning (#1241), so it has to exist somewhere the pane would find it —
-# not merely on the launcher's own PATH.
-printf '#!/usr/bin/env bash\nexit 0\n' > "$FAKE_BIN/pi"
-chmod +x "$FAKE_BIN/pi"
-
-# PANE_PATH is derived partly from `npm config get prefix`. Left to the real npm
-# it would splice whatever the host has installed into the path under test, and
-# the missing-binary cases below would pass or fail by accident of the machine.
-cat > "$FAKE_BIN/npm" <<'SHIM'
-#!/usr/bin/env bash
-printf '%s\n' "${MOSAIC_TEST_NPM_PREFIX:-/nonexistent}"
-SHIM
-chmod +x "$FAKE_BIN/npm"
-
-# PANE_PATH always ends in the system path. A host that installs these there can
-# not measure the missing-binary cases at all, and a green run would mean
-# nothing — so say so instead of passing.
-for host_binary in mosaic pi; do
-  if PATH=/usr/local/bin:/usr/bin:/bin command -v "$host_binary" >/dev/null 2>&1; then
-    fail "host provides '$host_binary' in the system path; missing-binary cases are not measurable here"
-  fi
-done
-
 write_generated() {
   local home="$1"
   local agent="$2"
@@ -123,19 +81,6 @@ MOSAIC_TMUX_SOCKET=mosaic-test
 EOF
   chmod 600 "$home/fleet/agents/$agent.env.generated"
   mkdir -p "$home/work"
-  install_pane_binaries "$home"
-}
-
-# `$PANE_HOME/.npm-global/bin` is one of the prefixes the launcher folds into
-# PANE_PATH, so this is the pane's own view of "installed", distinct from the
-# launcher's PATH. Tests that need a binary *absent* remove it from here.
-install_pane_binaries() {
-  local pane_home="$1"
-  mkdir -p "$pane_home/.npm-global/bin"
-  local binary
-  for binary in mosaic pi; do
-    ln -sf "$FAKE_BIN/$binary" "$pane_home/.npm-global/bin/$binary"
-  done
 }
 
 run_start() {
@@ -143,7 +88,6 @@ run_start() {
   local agent="$2"
   HOME="$home" PATH="$FAKE_BIN:$PATH" MOSAIC_TEST_TMUX_CALLS="$TMUX_CALLS" \
     MOSAIC_TEST_PANE_PID="${MOSAIC_TEST_PANE_PID:-}" \
-    MOSAIC_TEST_HELD_SESSIONS="${MOSAIC_TEST_HELD_SESSIONS:-}" \
     MOSAIC_TEST_HOME="$home" \
     MOSAIC_TEST_FLEET_OWNER=123e4567-e89b-12d3-a456-426614174000 \
     MOSAIC_HOME="$home" "$START" "$agent"
@@ -154,10 +98,7 @@ run_start() {
 HOME_VALID="$ROOT/valid"
 AGENT_VALID="coder0"
 write_generated "$HOME_VALID" "$AGENT_VALID"
-# A live pane PID is part of what "valid launch" means. Until #1241 this case
-# ran with none, so the suite's one success path was itself a dead pane the
-# launcher reported as fine.
-MOSAIC_TEST_PANE_PID=$$ run_start "$HOME_VALID" "$AGENT_VALID"
+run_start "$HOME_VALID" "$AGENT_VALID"
 valid_args=$(tr '\0' '\n' < "$TMUX_CALLS")
 echo "$valid_args" | grep -qF new-session || fail "valid generated projection did not reach tmux"
 echo "$valid_args" | grep -qF 'mosaic' || fail "fixed mosaic launcher command missing"
@@ -304,13 +245,6 @@ PANE_BASH_ENV="$ROOT/pane-boundary.bash-env"
 printf 'MOSAIC_RUNTIME_BIN=%s\n' "$FAKE_BIN" > \
   "$HOME_PANE_BOUNDARY/fleet/agents/coder-pane-boundary.env.local"
 chmod 600 "$HOME_PANE_BOUNDARY/fleet/agents/coder-pane-boundary.env.local"
-# This case does not go through run_start, so its pane binaries come from
-# MOSAIC_RUNTIME_BIN=$FAKE_BIN in the env.local written above — not from the
-# symlinks install_pane_binaries planted under the generated home, which this
-# launcher never consults because HOME here is the trusted parent. That is a
-# legitimate resolution path, but it means dropping MOSAIC_RUNTIME_BIN from
-# this case on the belief that the symlinks cover it would break the #1241
-# binary check rather than exercise it.
 LD_PRELOAD='/not/loaded/by-clean-bootstrap.so' \
 BASH_ENV="$PANE_BASH_ENV" \
 MOSAIC_UNTRUSTED_SENTINEL='must-not-reach-pane' \
@@ -324,7 +258,6 @@ PATH="$PANE_STALE_PATH" \
     "MOSAIC_TEST_HOME=$PANE_TRUSTED_HOME" \
     MOSAIC_TEST_FLEET_OWNER=123e4567-e89b-12d3-a456-426614174000 \
     MOSAIC_TEST_EXECUTE_PANE=1 \
-    "MOSAIC_TEST_PANE_PID=$$" \
     "$START" coder-pane-boundary
 pane_args=$(tr '\0' '\n' < "$TMUX_CALLS")
 echo "$pane_args" | grep -qxF "HOME=$PANE_TRUSTED_HOME" || \
@@ -459,75 +392,6 @@ echo "$interaction_policy_args" | grep -qF 'new-session' && \
 echo "$output" | grep -qF 'operator interaction service requires runtime pi' || \
   fail "interaction pinned-policy check did not follow strict parsing"
 
-# #1241. The pane runs `mosaic yolo <runtime>` against PANE_PATH. A binary
-# missing from that path is a launch failure, and it has to be named before the
-# session is created — after it, the diagnostic dies with the pane.
-assert_missing_pane_binary_rejected() {
-  local binary="$1"
-  local home="$ROOT/missing-$binary"
-  local agent="coder-missing-$binary"
-  write_generated "$home" "$agent"
-  rm -f "$home/.npm-global/bin/$binary"
-
-  : > "$TMUX_CALLS"
-  local output
-  if output=$(MOSAIC_TEST_PANE_PID=$$ run_start "$home" "$agent" 2>&1); then
-    fail "launch succeeded with '$binary' absent from the pane PATH"
-  fi
-  echo "$output" | grep -qF 'code=missing-binary' || fail "missing '$binary' diagnostic missing"
-  echo "$output" | grep -qF "'$binary'" || fail "missing-binary diagnostic did not name $binary"
-  if tr '\0' '\n' < "$TMUX_CALLS" | grep -qF new-session; then
-    fail "launcher created a session it knew would die ($binary absent)"
-  fi
-}
-
-assert_missing_pane_binary_rejected mosaic
-assert_missing_pane_binary_rejected pi
-
-# #1241. tmux destroys a session when its pane command exits, so no pane PID a
-# second after new-session means the runtime died on startup. This used to be a
-# WARNING about the heartbeat sidecar followed by exit 0 — three layers above it
-# then reported a fleet that was not running.
-: > "$TMUX_CALLS"
-HOME_DEAD_PANE="$ROOT/dead-pane"
-write_generated "$HOME_DEAD_PANE" "coder-dead-pane"
-if output=$(MOSAIC_TEST_PANE_PID='' run_start "$HOME_DEAD_PANE" coder-dead-pane 2>&1); then
-  fail "launcher reported success over a pane that did not survive"
-fi
-echo "$output" | grep -qF 'code=pane-did-not-survive' || fail "dead-pane diagnostic missing"
-if echo "$output" | grep -qiF 'heartbeat'; then
-  fail "dead pane is still being reported as a heartbeat-sidecar problem"
-fi
-tr '\0' '\n' < "$TMUX_CALLS" | grep -qF new-session || \
-  fail "dead-pane case did not reach the launch it is measuring"
-
-# #1241, the other way a pane fails. Above, tmux destroyed the session and
-# has-session said so. Here the session is still there and no PID comes back
-# after the retries — a different fault (the pane is alive but unusable, or
-# tmux is answering inconsistently) that an operator has to be told apart from
-# a runtime that died on startup.
-#
-# This case exists because the branch that handles it shipped with nothing able
-# to reach it: the shim answered has-session only for the holder, so every
-# non-holder agent landed in the session-is-gone branch no matter what. A
-# defensive branch nothing exercises is the same shape as the bug this whole
-# change is about, one layer down.
-: > "$TMUX_CALLS"
-HOME_NO_PID="$ROOT/pane-no-pid"
-write_generated "$HOME_NO_PID" "coder-no-pid"
-if output=$(MOSAIC_TEST_PANE_PID='' MOSAIC_TEST_HELD_SESSIONS='=coder-no-pid:0.0' \
-  run_start "$HOME_NO_PID" coder-no-pid 2>&1); then
-  fail "launcher reported success over a session with no resolvable pane PID"
-fi
-echo "$output" | grep -qF 'code=pane-pid-unresolved' || \
-  fail "session-present/no-PID was not reported as pane-pid-unresolved: $output"
-if echo "$output" | grep -qF 'code=pane-did-not-survive'; then
-  fail "a session tmux still reports was diagnosed as a destroyed session"
-fi
-if echo "$output" | grep -qiF 'heartbeat'; then
-  fail "an unresolvable pane PID is still being reported as a heartbeat-sidecar problem"
-fi
-
 # Exact stop derives the socket exclusively from the validated generated
 # projection and ignores an ambient socket supplied by the caller.
 : > "$TMUX_CALLS"