diff --git a/internal/orchestrator/orchestrator.go b/internal/orchestrator/orchestrator.go
index 6141c95..4f82922 100644
--- a/internal/orchestrator/orchestrator.go
+++ b/internal/orchestrator/orchestrator.go
@@ -716,6 +716,7 @@ func (o *Orchestrator) buildPlanPrompt(task *tasks.Task) string {
 	if o.runMeta != nil && o.runMeta.Branch != "" {
 		branchInstruction = fmt.Sprintf("\n   Create your feature branch from `%s`.", o.runMeta.Branch)
 	}
+	taskGuidance := o.buildTaskSpecificPlanGuidance(task)
 
 	return fmt.Sprintf(`You are a planning agent. Create a detailed execution plan for this task.
 
@@ -733,7 +734,7 @@ Description: %s
    Nightshift-Ref: https://github.com/marcus/nightshift
 4. Analyze the task requirements
 5. Identify files that need to be modified
-6. Create step-by-step implementation plan
+6. Create step-by-step implementation plan%s
 7. Output only valid JSON (no markdown, no extra text). The output is read by a machine. Use this schema:
 
 {
@@ -741,7 +742,7 @@ Description: %s
   "files": ["file1.go", "file2.go", ...],
   "description": "overall approach"
 }
-`, task.ID, task.Title, task.Description, branchInstruction, task.Type)
+`, task.ID, task.Title, task.Description, branchInstruction, task.Type, taskGuidance)
 }
 
 func (o *Orchestrator) buildImplementPrompt(task *tasks.Task, plan *PlanOutput, iteration int) string {
@@ -754,6 +755,7 @@ func (o *Orchestrator) buildImplementPrompt(task *tasks.Task, plan *PlanOutput,
 	if o.runMeta != nil && o.runMeta.Branch != "" {
 		branchInstruction = fmt.Sprintf("\n   Checkout `%s` before creating your feature branch.", o.runMeta.Branch)
 	}
+	taskGuidance := o.buildTaskSpecificImplementGuidance(task)
 
 	return fmt.Sprintf(`You are an implementation agent. Execute the plan for this task.
 
@@ -776,14 +778,51 @@ Description: %s
    Nightshift-Ref: https://github.com/marcus/nightshift
 2. Implement the plan step by step
 3. Make all necessary code changes
-4. Ensure tests pass
+4. Ensure tests pass%s
 5. Output a summary as JSON:
 
 {
   "files_modified": ["file1.go", ...],
   "summary": "what was done"
 }
-`, task.ID, task.Title, task.Description, plan.Description, plan.Steps, iterationNote, branchInstruction, task.Type)
+`, task.ID, task.Title, task.Description, plan.Description, plan.Steps, iterationNote, branchInstruction, task.Type, taskGuidance)
+}
+
+// buildTaskSpecificPlanGuidance appends extra planning instructions for tasks
+// whose safe default behavior needs more precision than the generic template.
+func (o *Orchestrator) buildTaskSpecificPlanGuidance(task *tasks.Task) string {
+	switch task.Type {
+	case tasks.TaskCommitNormalize:
+		return `
+
+## Task-Specific Guidance
+- Treat commit-normalize as a low-risk, prospective cleanup for new work and lightweight repo guidance.
+- Inspect recent commits first and prefer the repository's existing commit style when it is clear.
+- If the repository has no consistent style, use a concise conventional format for new commit messages.
+- Preserve required trailers and any project-specific footer lines.
+- Keep subjects concise and avoid plans that rewrite published or shared history.`
+	default:
+		return ""
+	}
+}
+
+// buildTaskSpecificImplementGuidance keeps built-in low-risk tasks scoped to
+// safe actions. commit-normalize should standardize future work, not rewrite
+// existing shared history.
+func (o *Orchestrator) buildTaskSpecificImplementGuidance(task *tasks.Task) string {
+	switch task.Type {
+	case tasks.TaskCommitNormalize:
+		return `
+
+## Task-Specific Guidance
+- Prefer the repository's established commit message style when present; otherwise use a clear conventional format.
+- Preserve required trailers and any project-specific footer lines on new commits you create.
+- Keep commit messages concise.
+- Standardize prospectively via new commits and lightweight repo guidance; do not rewrite published history.
+- Do not rebase, force-push, or otherwise rewrite shared branch history.`
+	default:
+		return ""
+	}
 }
 
 func (o *Orchestrator) buildReviewPrompt(task *tasks.Task, impl *ImplementOutput) string {
diff --git a/internal/orchestrator/orchestrator_test.go b/internal/orchestrator/orchestrator_test.go
index 45bff5c..40332ea 100644
--- a/internal/orchestrator/orchestrator_test.go
+++ b/internal/orchestrator/orchestrator_test.go
@@ -468,6 +468,80 @@ func TestBuildPrompts(t *testing.T) {
 	}
 }
 
+func TestBuildPlanPrompt_CommitNormalizeIncludesTaskSpecificGuidance(t *testing.T) {
+	o := New()
+	task := &tasks.Task{
+		ID:          "commit-normalize:/repo",
+		Title:       "Commit Message Normalizer",
+		Description: "Standardize commit message format safely",
+		Type:        tasks.TaskCommitNormalize,
+	}
+
+	prompt := o.buildPlanPrompt(task)
+	for _, want := range []string{
+		"Treat commit-normalize as a low-risk, prospective cleanup",
+		"prefer the repository's existing commit style",
+		"use a concise conventional format",
+		"Preserve required trailers",
+		"avoid plans that rewrite published or shared history",
+	} {
+		if !strings.Contains(prompt, want) {
+			t.Errorf("plan prompt missing %q\nGot:\n%s", want, prompt)
+		}
+	}
+}
+
+func TestBuildImplementPrompt_CommitNormalizeIncludesTaskSpecificGuidance(t *testing.T) {
+	o := New()
+	task := &tasks.Task{
+		ID:          "commit-normalize:/repo",
+		Title:       "Commit Message Normalizer",
+		Description: "Standardize commit message format safely",
+		Type:        tasks.TaskCommitNormalize,
+	}
+	plan := &PlanOutput{
+		Steps:       []string{"Inspect recent commits", "Update prompt guidance"},
+		Description: "Keep the task prospective and non-destructive.",
+	}
+
+	prompt := o.buildImplementPrompt(task, plan, 1)
+	for _, want := range []string{
+		"Prefer the repository's established commit message style when present",
+		"otherwise use a clear conventional format",
+		"Preserve required trailers",
+		"Keep commit messages concise",
+		"do not rewrite published history",
+		"Do not rebase, force-push, or otherwise rewrite shared branch history.",
+	} {
+		if !strings.Contains(prompt, want) {
+			t.Errorf("implement prompt missing %q\nGot:\n%s", want, prompt)
+		}
+	}
+}
+
+func TestBuildPrompts_GenericTaskDoesNotIncludeCommitNormalizeGuidance(t *testing.T) {
+	o := New()
+	task := &tasks.Task{
+		ID:          "lint-fix:/repo",
+		Title:       "Lint Fixes",
+		Description: "Automatically fix linting errors and style issues",
+		Type:        tasks.TaskLintFix,
+	}
+	plan := &PlanOutput{
+		Steps:       []string{"Run linter"},
+		Description: "Generic prompt path.",
+	}
+
+	planPrompt := o.buildPlanPrompt(task)
+	implPrompt := o.buildImplementPrompt(task, plan, 1)
+
+	for _, got := range []string{planPrompt, implPrompt} {
+		if strings.Contains(got, "Do not rebase, force-push, or otherwise rewrite shared branch history.") {
+			t.Errorf("generic task prompt unexpectedly included commit-normalize guidance\nGot:\n%s", got)
+		}
+	}
+}
+
 func TestExtractPRURL(t *testing.T) {
 	tests := []struct {
 		name  string
diff --git a/internal/tasks/tasks.go b/internal/tasks/tasks.go
index 2c7dabb..4490768 100644
--- a/internal/tasks/tasks.go
+++ b/internal/tasks/tasks.go
@@ -332,7 +332,7 @@ Apply safe updates directly, and leave concise follow-ups for anything uncertain
 		Type:            TaskCommitNormalize,
 		Category:        CategoryPR,
 		Name:            "Commit Message Normalizer",
-		Description:     "Standardize commit message format",
+		Description:     "Standardize commit message conventions for new work without rewriting shared history",
 		CostTier:        CostLow,
 		RiskLevel:       RiskLow,
 		DefaultInterval: 24 * time.Hour,
diff --git a/internal/tasks/tasks_test.go b/internal/tasks/tasks_test.go
index 03cdf18..516c9bb 100644
--- a/internal/tasks/tasks_test.go
+++ b/internal/tasks/tasks_test.go
@@ -489,3 +489,26 @@ func TestSpecificDefaultIntervalOverrides(t *testing.T) {
 		}
 	}
 }
+
+func TestCommitNormalizeDefinition(t *testing.T) {
+	def, err := GetDefinition(TaskCommitNormalize)
+	if err != nil {
+		t.Fatalf("GetDefinition(%q) error: %v", TaskCommitNormalize, err)
+	}
+
+	if def.Category != CategoryPR {
+		t.Errorf("Category = %d, want %d", def.Category, CategoryPR)
+	}
+	if def.CostTier != CostLow {
+		t.Errorf("CostTier = %d, want %d", def.CostTier, CostLow)
+	}
+	if def.RiskLevel != RiskLow {
+		t.Errorf("RiskLevel = %d, want %d", def.RiskLevel, RiskLow)
+	}
+	if def.DefaultInterval != 24*time.Hour {
+		t.Errorf("DefaultInterval = %v, want %v", def.DefaultInterval, 24*time.Hour)
+	}
+	if def.Description != "Standardize commit message conventions for new work without rewriting shared history" {
+		t.Errorf("Description = %q", def.Description)
+	}
+}
diff --git a/website/docs/task-reference.md b/website/docs/task-reference.md
index cb241df..5edf181 100644
--- a/website/docs/task-reference.md
+++ b/website/docs/task-reference.md
@@ -23,7 +23,7 @@ Fully formed, review-ready artifacts. These tasks create branches and open pull
 | `backward-compat` | Backward-Compatibility Checks | Check and ensure backward compatibility | Medium | Low | 7d |
 | `build-optimize` | Build Time Optimization | Optimize build configuration for faster builds | High | Medium | 7d |
 | `docs-backfill` | Documentation Backfiller | Generate missing documentation | Low | Low | 7d |
-| `commit-normalize` | Commit Message Normalizer | Standardize commit message format | Low | Low | 24h |
+| `commit-normalize` | Commit Message Normalizer | Standardize commit message conventions for new work without rewriting shared history | Low | Low | 24h |
 | `changelog-synth` | Changelog Synthesizer | Generate changelog from commits | Low | Low | 7d |
 | `release-notes` | Release Note Drafter | Draft release notes from changes | Low | Low | 7d |
 | `adr-draft` | ADR Drafter | Draft Architecture Decision Records | Medium | Low | 7d |