diff --git a/.github/workflows/lint-powershell.yml b/.github/workflows/lint-powershell.yml
index 4ae7cd670..0c8890c85 100644
--- a/.github/workflows/lint-powershell.yml
+++ b/.github/workflows/lint-powershell.yml
@@ -76,6 +76,10 @@ jobs:
         shell: pwsh
         run: ./tests/test-windows-model-activation.ps1
 
+      - name: Windows Dotenv Serializer Contract
+        shell: pwsh
+        run: ./tests/test-windows-dotenv-serializer.ps1
+
       - name: Windows Catalog Source Boundary Contract
         shell: pwsh
         run: ./tests/test-windows-catalog-selector.ps1
diff --git a/.github/workflows/test-linux.yml b/.github/workflows/test-linux.yml
index b5defb185..3dc0d8d9d 100644
--- a/.github/workflows/test-linux.yml
+++ b/.github/workflows/test-linux.yml
@@ -169,6 +169,9 @@ jobs:
       - name: Safe Env Loading Tests
         run: bash tests/test-safe-env.sh
 
+      - name: Dotenv Serializer Tests
+        run: bash tests/test-dotenv-serializer.sh
+
       - name: Mode Switch Tests
         run: bash tests/test-mode-switch-status.sh
 
diff --git a/ods/installers/macos/lib/env-generator.sh b/ods/installers/macos/lib/env-generator.sh
index c97d50c88..e812c1cdb 100755
--- a/ods/installers/macos/lib/env-generator.sh
+++ b/ods/installers/macos/lib/env-generator.sh
@@ -39,6 +39,11 @@ read_env_value() {
     grep -E "^${key}=" "$env_path" 2>/dev/null | sed -n '1p' | cut -d'=' -f2- | tr -d '\r' || true
 }
 
+# shellcheck source=../../../lib/dotenv-quote.sh
+_ODS_MACOS_ENV_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../../.." && pwd)"
+. "$_ODS_MACOS_ENV_ROOT/lib/dotenv-quote.sh"
+unset _ODS_MACOS_ENV_ROOT
+
 env_key_exists() {
     local env_path="$1"
     local key="$2"
@@ -535,13 +540,13 @@ CTX_SIZE=${MAX_CONTEXT}
 MODEL_RECOMMENDED_MODEL=${LLM_MODEL}
 MODEL_RECOMMENDED_GGUF=${GGUF_FILE}
 MODEL_RECOMMENDED_CONTEXT=${MAX_CONTEXT}
-MODEL_RECOMMENDATION_SOURCE=${MODEL_RECOMMENDATION_SOURCE:-installer_tier_map}
-MODEL_RECOMMENDATION_POLICY=${MODEL_RECOMMENDATION_POLICY:-tier-map}
-MODEL_RECOMMENDATION_CONFIDENCE=${MODEL_RECOMMENDATION_CONFIDENCE:-medium}
-MODEL_RECOMMENDATION_REASON=${MODEL_RECOMMENDATION_REASON:-Selected by installer tier ${tier} (${TIER_NAME}) for apple backend; benchmark locally after first launch.}
-MODEL_RECOMMENDED_ALTERNATIVES=${MODEL_RECOMMENDED_ALTERNATIVES:-}
+MODEL_RECOMMENDATION_SOURCE=$(dotenv_quote "${MODEL_RECOMMENDATION_SOURCE:-installer_tier_map}")
+MODEL_RECOMMENDATION_POLICY=$(dotenv_quote "${MODEL_RECOMMENDATION_POLICY:-tier-map}")
+MODEL_RECOMMENDATION_CONFIDENCE=$(dotenv_quote "${MODEL_RECOMMENDATION_CONFIDENCE:-medium}")
+MODEL_RECOMMENDATION_REASON=$(dotenv_quote "${MODEL_RECOMMENDATION_REASON:-Selected by installer tier ${tier} (${TIER_NAME}) for apple backend; benchmark locally after first launch.}")
+MODEL_RECOMMENDED_ALTERNATIVES=$(dotenv_quote "${MODEL_RECOMMENDED_ALTERNATIVES:-}")
 MODEL_PERFORMANCE_SOURCE=benchmark_required
-MODEL_PERFORMANCE_LABEL=Benchmark after first launch
+MODEL_PERFORMANCE_LABEL=$(dotenv_quote "Benchmark after first launch")
 GPU_BACKEND=apple
 HOST_RAM_GB=${SYSTEM_RAM_GB}
 N_GPU_LAYERS=${n_gpu_layers}
diff --git a/ods/installers/phases/06-directories.sh b/ods/installers/phases/06-directories.sh
index 5f909c8f7..b96437a39 100755
--- a/ods/installers/phases/06-directories.sh
+++ b/ods/installers/phases/06-directories.sh
@@ -47,6 +47,9 @@ else
     # shellcheck source=../lib/llama-memory-budget.sh
     source "$SCRIPT_DIR/installers/lib/llama-memory-budget.sh"
 
+    # shellcheck source=../../lib/dotenv-quote.sh
+    source "$SCRIPT_DIR/lib/dotenv-quote.sh"
+
     _phase06_rootless=false
     if [[ -f "$SCRIPT_DIR/lib/rootless-ownership.sh" ]]; then
         # shellcheck source=../../lib/rootless-ownership.sh
@@ -825,13 +828,13 @@ CTX_SIZE=${MAX_CONTEXT}
 MODEL_RECOMMENDED_MODEL=${MODEL_RECOMMENDED_MODEL_VALUE}
 MODEL_RECOMMENDED_GGUF=${MODEL_RECOMMENDED_GGUF_VALUE}
 MODEL_RECOMMENDED_CONTEXT=${MODEL_RECOMMENDED_CONTEXT_VALUE}
-MODEL_RECOMMENDATION_SOURCE=${MODEL_RECOMMENDATION_SOURCE:-installer_tier_map}
-MODEL_RECOMMENDATION_POLICY=${MODEL_RECOMMENDATION_POLICY:-tier-map}
-MODEL_RECOMMENDATION_CONFIDENCE=${MODEL_RECOMMENDATION_CONFIDENCE:-medium}
-MODEL_RECOMMENDATION_REASON=${MODEL_RECOMMENDATION_REASON:-Selected by installer tier ${TIER} (${TIER_NAME}) for ${GPU_BACKEND} backend; benchmark locally after first launch.}
-MODEL_RECOMMENDED_ALTERNATIVES=${MODEL_RECOMMENDED_ALTERNATIVES:-}
+MODEL_RECOMMENDATION_SOURCE=$(dotenv_quote "${MODEL_RECOMMENDATION_SOURCE:-installer_tier_map}")
+MODEL_RECOMMENDATION_POLICY=$(dotenv_quote "${MODEL_RECOMMENDATION_POLICY:-tier-map}")
+MODEL_RECOMMENDATION_CONFIDENCE=$(dotenv_quote "${MODEL_RECOMMENDATION_CONFIDENCE:-medium}")
+MODEL_RECOMMENDATION_REASON=$(dotenv_quote "${MODEL_RECOMMENDATION_REASON:-Selected by installer tier ${TIER} (${TIER_NAME}) for ${GPU_BACKEND} backend; benchmark locally after first launch.}")
+MODEL_RECOMMENDED_ALTERNATIVES=$(dotenv_quote "${MODEL_RECOMMENDED_ALTERNATIVES:-}")
 MODEL_PERFORMANCE_SOURCE=benchmark_required
-MODEL_PERFORMANCE_LABEL=Benchmark after first launch
+MODEL_PERFORMANCE_LABEL=$(dotenv_quote "Benchmark after first launch")
 GPU_BACKEND=${GPU_BACKEND}
 SYSTEM_RAM_GB=${RAM_GB:-0}
 N_GPU_LAYERS=${N_GPU_LAYERS_VALUE}
diff --git a/ods/installers/windows/lib/env-generator.ps1 b/ods/installers/windows/lib/env-generator.ps1
index a667748a5..47ee28d75 100644
--- a/ods/installers/windows/lib/env-generator.ps1
+++ b/ods/installers/windows/lib/env-generator.ps1
@@ -457,6 +457,22 @@ function New-SecureBase64 {
     return [Convert]::ToBase64String($buf)
 }
 
+function ConvertTo-ODSDotenvValue {
+    <# Serialize a value for Bash, Docker Compose, and ODS safe-env readers. #>
+    param([Parameter(Mandatory = $true)][AllowEmptyString()][string]$Value)
+
+    $text = ([string]$Value) -replace "`r", " " -replace "`n", " "
+    if ($text.IndexOf("'") -ge 0) {
+        # Bash and Compose disagree about \` inside double-quoted dotenv
+        # values. Normalize it only in this apostrophe fallback so both readers
+        # receive the same safe text.
+        $text = $text.Replace('`', 'ˋ')
+        $escaped = $text.Replace('\', '\\').Replace('"', '\"').Replace('$', '\$')
+        return '"' + $escaped + '"'
+    }
+    return "'" + $text + "'"
+}
+
 function New-ODSEnv {
     <#
     .SYNOPSIS
@@ -876,6 +892,13 @@ function New-ODSEnv {
     if ([string]::IsNullOrWhiteSpace($nGpuLayers)) { $nGpuLayers = "auto" }
 
     # Build .env content (matches Phase 06 format)
+    $recommendationSource = ConvertTo-ODSDotenvValue $(if ($TierConfig.RecommendationSource) { $TierConfig.RecommendationSource } else { "installer_tier_map" })
+    $recommendationPolicy = ConvertTo-ODSDotenvValue $(if ($TierConfig.RecommendationPolicy) { $TierConfig.RecommendationPolicy } else { "tier-map" })
+    $recommendationConfidence = ConvertTo-ODSDotenvValue $(if ($TierConfig.RecommendationConfidence) { $TierConfig.RecommendationConfidence } else { "medium" })
+    $recommendationReason = ConvertTo-ODSDotenvValue $(if ($TierConfig.RecommendationReason) { $TierConfig.RecommendationReason } else { "Selected by installer tier $Tier ($($TierConfig.TierName)) for $GpuBackend backend; benchmark locally after first launch." })
+    $recommendationAlternatives = ConvertTo-ODSDotenvValue $(if ($TierConfig.RecommendationAlternatives) { $TierConfig.RecommendationAlternatives } else { "" })
+    $performanceLabel = ConvertTo-ODSDotenvValue "Benchmark after first launch"
+
     $envContent = @"
 # ODS Configuration -- $($TierConfig.TierName) Edition
 # Generated by Windows installer v$($script:ODS_VERSION) on $timestamp
@@ -923,16 +946,16 @@ CTX_SIZE=$($TierConfig.MaxContext)
 MODEL_RECOMMENDED_MODEL=$($TierConfig.LlmModel)
 MODEL_RECOMMENDED_GGUF=$($TierConfig.GgufFile)
 MODEL_RECOMMENDED_CONTEXT=$($TierConfig.MaxContext)
-MODEL_RECOMMENDATION_SOURCE=$(if ($TierConfig.RecommendationSource) { $TierConfig.RecommendationSource } else { "installer_tier_map" })
-MODEL_RECOMMENDATION_POLICY=$(if ($TierConfig.RecommendationPolicy) { $TierConfig.RecommendationPolicy } else { "tier-map" })
-MODEL_RECOMMENDATION_CONFIDENCE=$(if ($TierConfig.RecommendationConfidence) { $TierConfig.RecommendationConfidence } else { "medium" })
-MODEL_RECOMMENDATION_REASON=$(if ($TierConfig.RecommendationReason) { $TierConfig.RecommendationReason } else { "Selected by installer tier $Tier ($($TierConfig.TierName)) for $GpuBackend backend; benchmark locally after first launch." })
-MODEL_RECOMMENDED_ALTERNATIVES=$(if ($TierConfig.RecommendationAlternatives) { $TierConfig.RecommendationAlternatives } else { "" })
+MODEL_RECOMMENDATION_SOURCE=$recommendationSource
+MODEL_RECOMMENDATION_POLICY=$recommendationPolicy
+MODEL_RECOMMENDATION_CONFIDENCE=$recommendationConfidence
+MODEL_RECOMMENDATION_REASON=$recommendationReason
+MODEL_RECOMMENDED_ALTERNATIVES=$recommendationAlternatives
 MODEL_RUNTIME_PROFILE=$(if ($TierConfig.RuntimeProfile) { $TierConfig.RuntimeProfile } else { "" })
 MODEL_RUNTIME_PROFILE_LABEL=$(if ($TierConfig.RuntimeProfileLabel) { $TierConfig.RuntimeProfileLabel } else { "" })
 MODEL_RUNTIME_PROFILE_SOURCE=$(if ($TierConfig.RuntimeProfileSource) { $TierConfig.RuntimeProfileSource } else { "" })
 MODEL_PERFORMANCE_SOURCE=benchmark_required
-MODEL_PERFORMANCE_LABEL=Benchmark after first launch
+MODEL_PERFORMANCE_LABEL=$performanceLabel
 GPU_BACKEND=$GpuBackend
 SYSTEM_RAM_GB=$SystemRamGB
 N_GPU_LAYERS=$nGpuLayers
diff --git a/ods/lib/dotenv-quote.sh b/ods/lib/dotenv-quote.sh
new file mode 100755
index 000000000..212bbb593
--- /dev/null
+++ b/ods/lib/dotenv-quote.sh
@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+# Serialize one value for the single-line .env grammar shared by Bash, Docker
+# Compose, and ODS's safe environment reader. Newlines cannot be represented
+# portably in that grammar, so normalize them to spaces rather than joining
+# words or allowing a second assignment line.
+dotenv_quote() {
+    local value="$1"
+    value="${value//$'\r'/ }"
+    value="${value//$'\n'/ }"
+
+    # Single quotes are literal in both Bash and Compose. When the value itself
+    # contains one, use their common double-quoted escape set. Bash requires a
+    # backslash before a literal backtick there, while Compose preserves that
+    # backslash, so normalize backticks to the visually equivalent modifier
+    # grave accent only in this rare fallback instead of corrupting one reader.
+    if [[ "$value" == *"'"* ]]; then
+        value="${value//\`/ˋ}"
+        value="${value//\\/\\\\}"
+        value="${value//\"/\\\"}"
+        value="${value//\$/\\\$}"
+        printf '"%s"\n' "$value"
+    else
+        printf "'%s'\n" "$value"
+    fi
+}
diff --git a/ods/lib/safe-env.sh b/ods/lib/safe-env.sh
index f1e079fd4..a85f0c1b9 100755
--- a/ods/lib/safe-env.sh
+++ b/ods/lib/safe-env.sh
@@ -48,6 +48,7 @@ load_env_file() {
         if [[ "$value" == '"'*'"' ]]; then
             value="${value#\"}"
             value="${value%\"}"
+            value="$(_safe_env_unescape_double_quoted "$value")"
         elif [[ "$value" == "'"*"'" ]]; then
             value="${value#\'}"
             value="${value%\'}"
diff --git a/ods/tests/smoke/installer-env-smoke.sh b/ods/tests/smoke/installer-env-smoke.sh
index eebc45573..47cdf3424 100755
--- a/ods/tests/smoke/installer-env-smoke.sh
+++ b/ods/tests/smoke/installer-env-smoke.sh
@@ -125,6 +125,8 @@ if bash -c "
     export LLM_MODEL=qwen3-1.7b
     export GGUF_FILE=Qwen3-1.7B-Q4_K_M.gguf
     export MAX_CONTEXT=4096
+    export MODEL_RECOMMENDATION_REASON='Arch-aware catalog policy (spark-aarch64): selected after fit check'
+    export MODEL_RECOMMENDED_ALTERNATIVES='deepseek-r1:32768:48;qwen-a3b:131072:35.48'
     export ODS_VERSION=2.1.0
     export ENABLE_VOICE=true
     export ENABLE_WORKFLOWS=true
@@ -186,6 +188,19 @@ fi
 echo ""
 echo "── .env schema validation ──"
 if [[ "$ENV_GENERATED" == true && -f "$INSTALL_DIR/.env" ]]; then
+    if bash -c '
+        set -a
+        source "$1"
+        set +a
+        [[ "$MODEL_RECOMMENDATION_REASON" == "Arch-aware catalog policy (spark-aarch64): selected after fit check" ]]
+        [[ "$MODEL_RECOMMENDED_ALTERNATIVES" == "deepseek-r1:32768:48;qwen-a3b:131072:35.48" ]]
+        [[ "$MODEL_PERFORMANCE_LABEL" == "Benchmark after first launch" ]]
+    ' _ "$INSTALL_DIR/.env"; then
+        pass "Generated model metadata is safe to source as dotenv"
+    else
+        fail "Generated model metadata breaks dotenv parsing"
+    fi
+
     if bash scripts/validate-env.sh "$INSTALL_DIR/.env" "$ROOT_DIR/.env.schema.json" 2>/dev/null; then
         pass ".env validates against schema"
     else
diff --git a/ods/tests/test-dotenv-serializer.sh b/ods/tests/test-dotenv-serializer.sh
new file mode 100755
index 000000000..b9d123614
--- /dev/null
+++ b/ods/tests/test-dotenv-serializer.sh
@@ -0,0 +1,79 @@
+#!/usr/bin/env bash
+set -u
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+. "$ROOT_DIR/lib/dotenv-quote.sh"
+. "$ROOT_DIR/lib/safe-env.sh"
+
+pass_count=0
+fail_count=0
+pass() { pass_count=$((pass_count + 1)); }
+fail() { printf 'FAIL: %s\n' "$1" >&2; fail_count=$((fail_count + 1)); }
+
+tmp_dir="$(mktemp -d)"
+trap 'rm -rf "$tmp_dir"' EXIT
+
+values=(
+    "Arch-aware catalog policy (spark-aarch64): selected after fit check"
+    "deepseek-r1:32768:48;qwen-a3b:131072:35.48"
+    'contains "literal double quotes"'
+    'cost is $HOME and ${UNSET_VAR} and $((1+1))'
+    'command $(touch pwned) substitution'
+    'backtick `id` here'
+    'C:\Users\dev\ods\models'
+    $'carriage\rreturn'
+    $'multi\nline'
+    ""
+    "it's a model"
+    'it'"'"'s $HOME $(touch pwned) `id` C:\path "dq"'
+)
+
+for value in "${values[@]}"; do
+    quoted="$(dotenv_quote "$value")"
+    expected="${value//$'\r'/ }"
+    expected="${expected//$'\n'/ }"
+    if [[ "$expected" == *"'"* ]]; then
+        expected="${expected//\`/ˋ}"
+    fi
+    printf 'TESTVAR=%s\n' "$quoted" > "$tmp_dir/.env"
+
+    unset TESTVAR
+    actual="$(set -a; source "$tmp_dir/.env"; set +a; printf '%s' "${TESTVAR-}")"
+    [[ "$actual" == "$expected" ]] \
+        && pass \
+        || fail "Bash source did not round-trip [$value]"
+
+    unset TESTVAR
+    load_env_file "$tmp_dir/.env"
+    [[ "${TESTVAR-}" == "$expected" ]] \
+        && pass \
+        || fail "safe-env did not round-trip [$value]"
+done
+
+[[ ! -e "$tmp_dir/pwned" ]] \
+    && pass \
+    || fail "serialized command substitution executed"
+[[ "$(dotenv_quote 'a;b $HOME')" == "$(dotenv_quote 'a;b $HOME')" ]] \
+    && pass \
+    || fail "serialization is not deterministic"
+
+# Compose has its own dotenv reader. Parsing every adversarial value proves the
+# generated file remains valid there without requiring an image pull in CI.
+if command -v docker >/dev/null 2>&1 && docker compose version >/dev/null 2>&1; then
+    : > "$tmp_dir/compose.env"
+    {
+        printf '%s\n' 'services:' '  probe:' '    image: busybox' '    environment:'
+        index=0
+        for value in "${values[@]}"; do
+            index=$((index + 1))
+            printf 'CASE%d=%s\n' "$index" "$(dotenv_quote "$value")" >> "$tmp_dir/compose.env"
+            printf '      CASE%d: ${CASE%d}\n' "$index" "$index"
+        done
+    } > "$tmp_dir/compose.yaml"
+    docker compose --env-file "$tmp_dir/compose.env" -f "$tmp_dir/compose.yaml" config >/dev/null 2>&1 \
+        && pass \
+        || fail "Docker Compose rejected serialized values"
+fi
+
+printf 'Results: %d passed, %d failed\n' "$pass_count" "$fail_count"
+[[ "$fail_count" -eq 0 ]]
diff --git a/ods/tests/test-safe-env.sh b/ods/tests/test-safe-env.sh
index 579c97c8f..873f18baa 100755
--- a/ods/tests/test-safe-env.sh
+++ b/ods/tests/test-safe-env.sh
@@ -141,5 +141,15 @@ load_env_file "$tmpdir/.env-quotes"
 [[ "${PLAIN_SQ:-}" == "plain" ]] || fail "PLAIN_SQ not unquoted (got: '${PLAIN_SQ:-}')"
 pass "load_env_file strips only matched surrounding quote pairs"
 
+echo "Test 13: load_env_file decodes the supported double-quoted escape set"
+unset FILE_ESCAPED 2>/dev/null || true
+cat > "$tmpdir/.env-escaped" << 'EOF'
+FILE_ESCAPED="it's \$HOME and \$(whoami) and \`id\` and C:\\path and \"dq\""
+EOF
+load_env_file "$tmpdir/.env-escaped"
+[[ "${FILE_ESCAPED:-}" == 'it'"'"'s $HOME and $(whoami) and `id` and C:\path and "dq"' ]] \
+    || fail "FILE_ESCAPED not decoded safely (got: ${FILE_ESCAPED:-})"
+pass "load_env_file decodes supported escapes without evaluation"
+
 echo ""
 echo "All safe-env tests passed."
diff --git a/ods/tests/test-windows-dotenv-serializer.ps1 b/ods/tests/test-windows-dotenv-serializer.ps1
new file mode 100644
index 000000000..18eb43551
--- /dev/null
+++ b/ods/tests/test-windows-dotenv-serializer.ps1
@@ -0,0 +1,30 @@
+$ErrorActionPreference = "Stop"
+
+$repoRoot = (Resolve-Path (Join-Path $PSScriptRoot "..")).Path
+. (Join-Path $repoRoot "installers/windows/lib/env-generator.ps1")
+
+$failures = 0
+function Assert-Equal([string]$Label, [string]$Expected, [string]$Actual) {
+    if ($Expected -ne $Actual) {
+        Write-Host "FAIL: $Label expected=[$Expected] actual=[$Actual]"
+        $script:failures++
+    } else {
+        Write-Host "PASS: $Label"
+    }
+}
+
+$simple = 'deepseek-r1:32768:48;qwen-a3b:131072:35.48'
+Assert-Equal "simple value" "'$simple'" (ConvertTo-ODSDotenvValue $simple)
+
+$special = 'cost is $HOME and $(whoami) and `id` and "dq" and C:\path'
+Assert-Equal "literal special characters" "'$special'" (ConvertTo-ODSDotenvValue $special)
+
+$compound = 'it''s $HOME and $(whoami) and `id` and "dq" and C:\path'
+$compoundExpected = '"it''s \$HOME and \$(whoami) and ˋidˋ and \"dq\" and C:\\path"'
+Assert-Equal "single quote fallback" $compoundExpected (ConvertTo-ODSDotenvValue $compound)
+
+Assert-Equal "empty value" "''" (ConvertTo-ODSDotenvValue "")
+Assert-Equal "line normalization" "'line break'" (ConvertTo-ODSDotenvValue "line`nbreak")
+Assert-Equal "deterministic" (ConvertTo-ODSDotenvValue 'a;b $HOME') (ConvertTo-ODSDotenvValue 'a;b $HOME')
+
+if ($failures -gt 0) { exit 1 }