diff --git a/CHANGELOG.md b/CHANGELOG.md
index 465acfd..7aeb509 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,14 @@ A `Migration` section is added to any release that bumps `schema_version`.
   published instead of failing. Release-artifact names and paths are now also
   validated against the character set the emitted upload shell can carry
   safely, since the path is spliced unquoted so its glob can expand
+- **generate:** Route the promote matrix input JSON (`DEFAULT_INPUTS` /
+  `ENV_INPUTS`) through the Build Deploy Matrices step `env:` map instead of
+  embedding it in a shell single-quote literal, and emit dispatch-input
+  defaults as properly escaped YAML single-quoted scalars. An apostrophe in an
+  ordinary input value (for example `message: "it's live"`) previously
+  generated a promote script that failed shell parsing on every promotion, and
+  a crafted value could have executed in the promote job; an apostrophe in a
+  `dispatch_inputs` default produced an invalid workflow document
 
 - **promote:** Record only the publishing component's own release marker
   (`version`, `sha`, `released_on`) under `latest_release.components.<name>`.
diff --git a/e2e/scenarios/66-input-value-quoting.yaml b/e2e/scenarios/66-input-value-quoting.yaml
new file mode 100644
index 0000000..367efcf
--- /dev/null
+++ b/e2e/scenarios/66-input-value-quoting.yaml
@@ -0,0 +1,97 @@
+name: "Input Value Quoting"
+description: |
+  Operator-authored input values are ordinary human text and may carry
+  apostrophes. The generated workflows must stay well-formed anyway:
+
+  1. Promote matrix inputs: the serialized DEFAULT_INPUTS / ENV_INPUTS JSON is
+     routed through the Build Deploy Matrices step env: map (YAML single-quoted,
+     embedded quotes doubled) and read back via quoted shell variables. The JSON
+     must never sit inside a shell single-quote literal in the run script, where
+     an apostrophe breaks parsing and a crafted value would execute.
+
+  2. Dispatch input defaults: a default containing an apostrophe must be
+     emitted as a valid YAML single-quoted scalar (embedded quote doubled) in
+     the workflow_dispatch inputs block.
+
+  Generator-output verification only. The harness localizes and parses every
+  generated workflow, so a malformed document fails the run outright.
+
+config:
+  trunk_branch: main
+  environments: [dev, prod]
+  builds:
+    - name: app
+      workflow: build.yaml
+      triggers: ["src/**"]
+  deploys:
+    - name: app
+      workflow: deploy.yaml
+      triggers: ["src/**"]
+      inputs:
+        message: "it's live"
+      env_inputs:
+        prod:
+          message: "don't stop"
+  dispatch_inputs:
+    notice:
+      type: string
+      default: "it's enabled"
+      description: "Operator note"
+
+# The deploy callback declares the message input the generated promote
+# workflow threads through the matrix, keeping the reusable-workflow call
+# valid.
+setup_workflows:
+  ".github/workflows/deploy.yaml": |
+    name: deploy
+    on:
+      workflow_call:
+        inputs:
+          environment:
+            required: false
+            type: string
+          sha:
+            required: false
+            type: string
+          message:
+            required: false
+            type: string
+    jobs:
+      deploy:
+        runs-on: ubuntu-latest
+        steps:
+          - run: echo "deploy"
+
+steps:
+  - name: "Seed source; assert apostrophe-bearing values emit well-formed workflows"
+    action: commit
+    commit:
+      message: "seed source"
+      files:
+        src/main.go: |
+          package main
+
+          func main() {}
+    expect:
+      workflow_files:
+        - path: ".github/workflows/promote.yaml"
+          contains:
+            # Input JSON is env-routed on the step, YAML-quoted with the
+            # embedded apostrophe doubled.
+            - "DEFAULT_INPUTS_APP: '{\"message\":\"it''s live\"}'"
+            - "ENV_INPUTS_APP: '{\"prod\":{\"message\":\"don''t stop\"}}'"
+            # The script reads the JSON back through quoted variables.
+            - "DEFAULT_INPUTS=\"$DEFAULT_INPUTS_APP\""
+            - "ENV_INPUTS=\"$ENV_INPUTS_APP\""
+          not_contains:
+            # The broken form: JSON inside a shell single-quote literal.
+            - "DEFAULT_INPUTS='{"
+            - "ENV_INPUTS='{"
+        - path: ".github/workflows/orchestrate.yaml"
+          contains:
+            - "      notice:"
+            # Valid YAML single-quoted scalar: embedded apostrophe doubled.
+            - "        default: 'it''s enabled'"
+          not_contains:
+            # The broken form: raw apostrophe terminating the scalar early.
+            - "default: 'it's enabled'"
diff --git a/internal/generate/generator.go b/internal/generate/generator.go
index 0c6e58a..5c7f486 100644
--- a/internal/generate/generator.go
+++ b/internal/generate/generator.go
@@ -776,7 +776,7 @@ func (g *Generator) writeWorkflowTriggers(sb *strings.Builder) {
 				}
 			}
 			if di.Default != nil {
-				fmt.Fprintf(sb, "        default: '%v'\n", di.Default)
+				fmt.Fprintf(sb, "        default: %s\n", yamlSingleQuote(fmt.Sprintf("%v", di.Default)))
 			}
 			if di.IsRequired() {
 				sb.WriteString("        required: true\n")
diff --git a/internal/generate/input_passthrough_test.go b/internal/generate/input_passthrough_test.go
index e714325..f3f076d 100644
--- a/internal/generate/input_passthrough_test.go
+++ b/internal/generate/input_passthrough_test.go
@@ -196,7 +196,7 @@ func TestPromoteLiteralInputsUnchanged(t *testing.T) {
 	result, err := gen.Generate()
 	require.NoError(t, err)
 
-	assert.Contains(t, result, `DEFAULT_INPUTS='{"cluster":"dev-eks"}'`)
+	assert.Contains(t, result, `DEFAULT_INPUTS_APP: '{"cluster":"dev-eks"}'`)
 	assert.Contains(t, result, `"prod":{"cluster":"prod-eks"}`)
 	assert.Contains(t, result, "cluster: ${{ matrix.cluster }}")
 }
diff --git a/internal/generate/input_quoting_test.go b/internal/generate/input_quoting_test.go
new file mode 100644
index 0000000..d61b68c
--- /dev/null
+++ b/internal/generate/input_quoting_test.go
@@ -0,0 +1,180 @@
+package generate
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gopkg.in/yaml.v3"
+
+	"github.com/stablekernel/cascade/internal/config"
+)
+
+// requireShellParseable writes script to a temp file and asserts bash -n
+// accepts it. The generated matrix-building step must stay parseable no
+// matter what characters an operator puts in an input value.
+func requireShellParseable(t *testing.T, script string) {
+	t.Helper()
+	path := filepath.Join(t.TempDir(), "step.sh")
+	require.NoError(t, os.WriteFile(path, []byte(script), 0o600))
+	out, err := exec.Command("bash", "-n", path).CombinedOutput()
+	require.NoError(t, err, "bash -n rejected the emitted run script:\n%s\nscript:\n%s", out, script)
+}
+
+// findStep parses a generated workflow and returns the step with the given
+// name from any job, proving along the way that the document is valid YAML.
+func findStep(t *testing.T, content, stepName string) map[string]interface{} {
+	t.Helper()
+	var doc struct {
+		Jobs map[string]struct {
+			Steps []map[string]interface{} `yaml:"steps"`
+		} `yaml:"jobs"`
+	}
+	require.NoError(t, yaml.Unmarshal([]byte(content), &doc), "generated workflow must be valid YAML")
+	for _, job := range doc.Jobs {
+		for _, step := range job.Steps {
+			if step["name"] == stepName {
+				return step
+			}
+		}
+	}
+	require.Failf(t, "step not found", "step %q not present in generated workflow", stepName)
+	return nil
+}
+
+// TestBuildDeployMatrices_ApostropheInputValue_EnvRoutedAndShellParseable
+// covers the promote matrix input sink: an ordinary human value containing an
+// apostrophe (and any crafted value) must never sit inside a shell quote
+// literal in the emitted run script. The JSON blobs are routed through the
+// step env: map and referenced as quoted shell variables, so the script
+// parses regardless of input content.
+func TestBuildDeployMatrices_ApostropheInputValue_EnvRoutedAndShellParseable(t *testing.T) {
+	cfg := &config.TrunkConfig{
+		TrunkBranch:  "main",
+		Environments: config.EnvNames("dev", "prod"),
+		Deploys: []config.DeployConfig{
+			{
+				Name:     "app",
+				Workflow: ".github/workflows/deploy-app.yaml",
+				Inputs: map[string]interface{}{
+					"message": "it's live",
+				},
+				EnvInputs: map[string]map[string]interface{}{
+					"prod": {"message": "don't y'all stop"},
+				},
+			},
+		},
+	}
+
+	gen := NewPromoteGenerator(cfg, "")
+	content, err := gen.Generate()
+	require.NoError(t, err)
+
+	step := findStep(t, content, "Build Deploy Matrices")
+
+	// The run script must be shell-parseable even with apostrophes in values.
+	run, ok := step["run"].(string)
+	require.True(t, ok, "Build Deploy Matrices step has no run script")
+	requireShellParseable(t, run)
+
+	// The JSON reaches the shell through env: indirection, never through a
+	// quoted literal inside the script.
+	env, ok := step["env"].(map[string]interface{})
+	require.True(t, ok, "Build Deploy Matrices step has no env map")
+	assert.Equal(t, `{"message":"it's live"}`, env["DEFAULT_INPUTS_APP"])
+	assert.Equal(t, `{"prod":{"message":"don't y'all stop"}}`, env["ENV_INPUTS_APP"])
+	assert.NotContains(t, run, "DEFAULT_INPUTS='")
+	assert.NotContains(t, run, "ENV_INPUTS='")
+	assert.Contains(t, run, `DEFAULT_INPUTS="$DEFAULT_INPUTS_APP"`)
+	assert.Contains(t, run, `ENV_INPUTS="$ENV_INPUTS_APP"`)
+}
+
+// TestBuildDeployMatrices_PlainInputValues_ShellParseable pins the same
+// guarantee for apostrophe-free values across multiple deploys: the script
+// still parses and each deploy gets its own env-routed JSON pair.
+func TestBuildDeployMatrices_PlainInputValues_ShellParseable(t *testing.T) {
+	cfg := &config.TrunkConfig{
+		TrunkBranch:  "main",
+		Environments: config.EnvNames("dev", "prod"),
+		Deploys: []config.DeployConfig{
+			{
+				Name:     "app",
+				Workflow: ".github/workflows/deploy-app.yaml",
+				Inputs: map[string]interface{}{
+					"cluster": "dev-eks",
+				},
+				EnvInputs: map[string]map[string]interface{}{
+					"prod": {"cluster": "prod-eks"},
+				},
+			},
+			{
+				Name:     "infra-core",
+				Workflow: ".github/workflows/deploy-infra.yaml",
+				Inputs: map[string]interface{}{
+					"stack": "main",
+				},
+			},
+		},
+	}
+
+	gen := NewPromoteGenerator(cfg, "")
+	content, err := gen.Generate()
+	require.NoError(t, err)
+
+	step := findStep(t, content, "Build Deploy Matrices")
+	run, ok := step["run"].(string)
+	require.True(t, ok, "Build Deploy Matrices step has no run script")
+	requireShellParseable(t, run)
+
+	env, ok := step["env"].(map[string]interface{})
+	require.True(t, ok, "Build Deploy Matrices step has no env map")
+	assert.Equal(t, `{"cluster":"dev-eks"}`, env["DEFAULT_INPUTS_APP"])
+	assert.Equal(t, `{"prod":{"cluster":"prod-eks"}}`, env["ENV_INPUTS_APP"])
+	assert.Equal(t, `{"stack":"main"}`, env["DEFAULT_INPUTS_INFRA_CORE"])
+	assert.Equal(t, `{}`, env["ENV_INPUTS_INFRA_CORE"])
+}
+
+// TestGenerator_DispatchInputDefaultWithApostrophe_ValidYAML covers the
+// dispatch-input default sink: an apostrophe in a default value must produce
+// a valid YAML scalar (single-quote style doubles embedded quotes), so the
+// emitted orchestrate workflow parses and the value round-trips intact.
+func TestGenerator_DispatchInputDefaultWithApostrophe_ValidYAML(t *testing.T) {
+	tmpDir := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(tmpDir, ".github/workflows"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(tmpDir, ".github/workflows/build.yaml"), []byte("on:\n  workflow_call:\n"), 0o644))
+
+	cfg := &config.TrunkConfig{
+		TrunkBranch:  "main",
+		Environments: config.EnvNames("dev"),
+		Builds: []config.BuildConfig{
+			{Name: "app", Workflow: ".github/workflows/build.yaml", Triggers: []string{"src/**"}},
+		},
+		DispatchInputs: map[string]config.DispatchInput{
+			"greeting": {
+				Type:        config.DispatchInputTypeString,
+				Default:     "it's a default",
+				Description: "operator note",
+			},
+		},
+	}
+
+	gen := NewGenerator(cfg, tmpDir)
+	result, err := gen.Generate()
+	require.NoError(t, err)
+
+	var doc struct {
+		On struct {
+			WorkflowDispatch struct {
+				Inputs map[string]struct {
+					Default interface{} `yaml:"default"`
+				} `yaml:"inputs"`
+			} `yaml:"workflow_dispatch"`
+		} `yaml:"on"`
+	}
+	require.NoError(t, yaml.Unmarshal([]byte(result), &doc), "generated orchestrate workflow must be valid YAML")
+	require.Contains(t, doc.On.WorkflowDispatch.Inputs, "greeting")
+	assert.Equal(t, "it's a default", doc.On.WorkflowDispatch.Inputs["greeting"].Default)
+}
diff --git a/internal/generate/promote.go b/internal/generate/promote.go
index fac5d01..aa6d982 100644
--- a/internal/generate/promote.go
+++ b/internal/generate/promote.go
@@ -237,6 +237,19 @@ func (g *PromoteGenerator) writeMatrixBuildingStep(sb *strings.Builder) {
 	sb.WriteString("        id: build-matrices\n")
 	sb.WriteString("        env:\n")
 	sb.WriteString("          PROMOTION_RESULT: ${{ steps.preflight.outputs.promotion_result }}\n")
+	// Route each deploy's serialized input JSON through env: indirection so
+	// operator-authored values never appear inside a shell quote literal in
+	// the run script (same pattern as the dispatch-input handling in the
+	// external update workflow).
+	for _, d := range g.config.Deploys {
+		if len(d.Inputs) == 0 {
+			continue
+		}
+		upper := strings.ToUpper(strings.ReplaceAll(d.Name, "-", "_"))
+		defaultInputsJSON, envInputsJSON := g.matrixInputsJSON(&d)
+		fmt.Fprintf(sb, "          DEFAULT_INPUTS_%s: %s\n", upper, yamlSingleQuote(defaultInputsJSON))
+		fmt.Fprintf(sb, "          ENV_INPUTS_%s: %s\n", upper, yamlSingleQuote(envInputsJSON))
+	}
 	sb.WriteString("        run: |\n")
 	sb.WriteString("          # Extract promotions array from promotion result\n")
 	sb.WriteString("          PROMOTIONS=$(echo \"$PROMOTION_RESULT\" | jq -c '.promotions // []')\n")
@@ -252,8 +265,8 @@ func (g *PromoteGenerator) writeMatrixBuildingStep(sb *strings.Builder) {
 		fmt.Fprintf(sb, "          # Build matrix for deploy: %s\n", d.Name)
 		fmt.Fprintf(sb, "          MATRIX_%s='['\n", strings.ToUpper(outputName))
 
-		// Serialize default inputs and env-specific inputs as JSON for bash
-		g.writeMatrixBuildingLogic(sb, &d, outputName)
+		// The input JSON is env-routed on the step; the logic reads it back.
+		g.writeMatrixBuildingLogic(sb, outputName)
 
 		fmt.Fprintf(sb, "          MATRIX_%s=\"${MATRIX_%s}]\"\n", strings.ToUpper(outputName), strings.ToUpper(outputName))
 		fmt.Fprintf(sb, "          echo \"deploy_%s_matrix=$MATRIX_%s\" >> \"$GITHUB_OUTPUT\"\n", outputName, strings.ToUpper(outputName))
@@ -385,24 +398,32 @@ func (g *PromoteGenerator) matrixEnvInputs(deploy *config.DeployConfig) map[stri
 	return out
 }
 
-// writeMatrixBuildingLogic generates the bash logic to build a matrix for a single deploy.
-// It iterates through promotions and builds matrix entries with resolved inputs.
-func (g *PromoteGenerator) writeMatrixBuildingLogic(sb *strings.Builder, deploy *config.DeployConfig, outputName string) {
-	// Serialize default inputs (passthrough expressions excluded; state.*
-	// refs resolved per-env into env_inputs below).
+// matrixInputsJSON serializes a deploy's default inputs and env_inputs as
+// compact JSON (passthrough expressions excluded; state.* refs resolved
+// per-env into env_inputs).
+func (g *PromoteGenerator) matrixInputsJSON(deploy *config.DeployConfig) (string, string) {
 	defaultInputsJSON, err := json.Marshal(g.matrixDefaultInputs(deploy))
 	if err != nil {
 		defaultInputsJSON = []byte("{}")
 	}
-
-	// Serialize env_inputs (passthrough excluded, state.* resolved).
 	envInputsJSON, err := json.Marshal(g.matrixEnvInputs(deploy))
 	if err != nil {
 		envInputsJSON = []byte("{}")
 	}
+	return string(defaultInputsJSON), string(envInputsJSON)
+}
 
-	fmt.Fprintf(sb, "          DEFAULT_INPUTS='%s'\n", string(defaultInputsJSON))
-	fmt.Fprintf(sb, "          ENV_INPUTS='%s'\n", string(envInputsJSON))
+// writeMatrixBuildingLogic generates the bash logic to build a matrix for a single deploy.
+// It iterates through promotions and builds matrix entries with resolved inputs.
+func (g *PromoteGenerator) writeMatrixBuildingLogic(sb *strings.Builder, outputName string) {
+	// The serialized input JSON carries operator-authored values verbatim, so
+	// it must never sit inside a shell quote literal in the script (a single
+	// quote in an ordinary value would break parsing; a crafted value would
+	// execute). The step env: map carries the JSON and the script reads it
+	// back through quoted variable references.
+	upper := strings.ToUpper(outputName)
+	fmt.Fprintf(sb, "          DEFAULT_INPUTS=\"$DEFAULT_INPUTS_%s\"\n", upper)
+	fmt.Fprintf(sb, "          ENV_INPUTS=\"$ENV_INPUTS_%s\"\n", upper)
 	sb.WriteString("          \n")
 	sb.WriteString("          # Iterate through promotions\n")
 	sb.WriteString("          FIRST=true\n")
diff --git a/internal/generate/promote_matrix_script_test.go b/internal/generate/promote_matrix_script_test.go
index 7b517f7..dc7879d 100644
--- a/internal/generate/promote_matrix_script_test.go
+++ b/internal/generate/promote_matrix_script_test.go
@@ -15,9 +15,11 @@ import (
 	"github.com/stablekernel/cascade/internal/config"
 )
 
-// extractStepRun parses a generated workflow and returns the run script of the
-// step with the given id, failing the test if no such step exists.
-func extractStepRun(t *testing.T, workflowYAML, stepID string) string {
+// extractStepRun parses a generated workflow and returns the run script of
+// the step with the given id plus its env: entries verbatim (the caller
+// overrides expression-valued ones like PROMOTION_RESULT), failing the test
+// if no such step exists.
+func extractStepRun(t *testing.T, workflowYAML, stepID string) (string, map[string]string) {
 	t.Helper()
 
 	var wf map[string]interface{}
@@ -43,12 +45,20 @@ func extractStepRun(t *testing.T, workflowYAML, stepID string) string {
 			if step["id"] == stepID {
 				run, ok := step["run"].(string)
 				require.True(t, ok && run != "", "step %q has no run script", stepID)
-				return run
+				env := make(map[string]string)
+				if rawEnv, ok := step["env"].(map[string]interface{}); ok {
+					for k, v := range rawEnv {
+						if val, ok := v.(string); ok {
+							env[k] = val
+						}
+					}
+				}
+				return run, env
 			}
 		}
 	}
 	t.Fatalf("step %q not found in generated workflow", stepID)
-	return ""
+	return "", nil
 }
 
 // TestGeneratedMatrixScript_ResolvesDeployInputsAtRuntime executes the emitted
@@ -93,7 +103,7 @@ func TestGeneratedMatrixScript_ResolvesDeployInputsAtRuntime(t *testing.T) {
 	content, err := gen.Generate()
 	require.NoError(t, err)
 
-	script := extractStepRun(t, content, "build-matrices")
+	script, stepEnv := extractStepRun(t, content, "build-matrices")
 
 	// runScript executes the emitted step exactly as GitHub Actions would
 	// (bash -e), feeding the preflight promotion result through the same env
@@ -105,7 +115,14 @@ func TestGeneratedMatrixScript_ResolvesDeployInputsAtRuntime(t *testing.T) {
 		require.NoError(t, os.WriteFile(outFile, nil, 0o600))
 
 		cmd := exec.Command("bash", "-e", "-c", script)
-		cmd.Env = append(os.Environ(),
+		cmd.Env = os.Environ()
+		// Wire the step's env: entries (the env-routed input JSON) exactly as
+		// GitHub Actions would; test-controlled values are appended last so
+		// they override the expression-valued entries.
+		for k, v := range stepEnv {
+			cmd.Env = append(cmd.Env, k+"="+v)
+		}
+		cmd.Env = append(cmd.Env,
 			"PROMOTION_RESULT="+promotionResult,
 			"GITHUB_OUTPUT="+outFile,
 		)
diff --git a/internal/generate/promote_test.go b/internal/generate/promote_test.go
index 313e1d0..45e544c 100644
--- a/internal/generate/promote_test.go
+++ b/internal/generate/promote_test.go
@@ -995,8 +995,10 @@ func TestPreflightDeployMatrixOutputs(t *testing.T) {
 	// Should have matrix building logic for app deploy
 	assert.Contains(t, content, "# Build matrix for deploy: app")
 	assert.Contains(t, content, "MATRIX_APP='['")
-	assert.Contains(t, content, `DEFAULT_INPUTS='{"cluster":"dev-eks","environment":"${{ matrix.environment }}","sha":"${{ matrix.sha }}"}'`)
-	assert.Contains(t, content, `ENV_INPUTS='{"prod":{"cluster":"prod-eks"}}'`)
+	assert.Contains(t, content, `DEFAULT_INPUTS_APP: '{"cluster":"dev-eks","environment":"${{ matrix.environment }}","sha":"${{ matrix.sha }}"}'`)
+	assert.Contains(t, content, `ENV_INPUTS_APP: '{"prod":{"cluster":"prod-eks"}}'`)
+	assert.Contains(t, content, `DEFAULT_INPUTS="$DEFAULT_INPUTS_APP"`)
+	assert.Contains(t, content, `ENV_INPUTS="$ENV_INPUTS_APP"`)
 
 	// Should have matrix building logic for infra deploy
 	assert.Contains(t, content, "# Build matrix for deploy: infra")
diff --git a/internal/generate/yaml_quote.go b/internal/generate/yaml_quote.go
new file mode 100644
index 0000000..1df1df1
--- /dev/null
+++ b/internal/generate/yaml_quote.go
@@ -0,0 +1,12 @@
+package generate
+
+import "strings"
+
+// yamlSingleQuote renders s as a YAML single-quoted scalar. The only escape
+// in that style is doubling embedded single quotes, so any operator-authored
+// value (apostrophes included) round-trips intact instead of breaking the
+// emitted document. Callers pass single-line values; JSON-serialized input
+// blobs and dispatch-input defaults never carry raw newlines.
+func yamlSingleQuote(s string) string {
+	return "'" + strings.ReplaceAll(s, "'", "''") + "'"
+}