diff --git a/internal/adapter/cli/run.go b/internal/adapter/cli/run.go
index 1b860d1..9ab33cf 100644
--- a/internal/adapter/cli/run.go
+++ b/internal/adapter/cli/run.go
@@ -16,6 +16,7 @@ import (
 	artifactadapter "gitea.maximumdirect.net/eric/scriptorium/internal/artifact"
 	"gitea.maximumdirect.net/eric/scriptorium/internal/defaults"
 	"gitea.maximumdirect.net/eric/scriptorium/internal/domain"
+	renderformat "gitea.maximumdirect.net/eric/scriptorium/internal/format"
 	"gitea.maximumdirect.net/eric/scriptorium/internal/llm"
 	"gitea.maximumdirect.net/eric/scriptorium/internal/profile"
 	"gitea.maximumdirect.net/eric/scriptorium/internal/prompt"
@@ -56,6 +57,11 @@ type runConfig struct {
 	timeoutSet     bool
 }
 
+type renderConfig struct {
+	runConfig
+	outputFormat renderformat.PreparedRunOutputFormat
+}
+
 type serveConfig struct {
 	addr       string
 	promptDir  string
@@ -83,6 +89,8 @@ func Run(args []string, stdout, stderr io.Writer) int {
 	switch args[0] {
 	case "run":
 		return runCommand(args[1:], stdout, stderr)
+	case "render":
+		return renderCommand(args[1:], stdout, stderr)
 	case "serve":
 		return serveCommand(args[1:], stderr)
 	default:
@@ -99,24 +107,11 @@ func runCommand(args []string, stdout, stderr io.Writer) int {
 		return ExitRuntimeError
 	}
 
-	inputMappings, err := parseMappings(cfg.inputRaw, false)
+	req, err := buildRunRequestFromConfig(cfg)
 	if err != nil {
-		fmt.Fprintf(stderr, "input parse error: %v\n", err)
+		fmt.Fprintf(stderr, "run parse error: %v\n", err)
 		return ExitRuntimeError
 	}
-	varMappings := map[string]string{}
-	if len(cfg.varRaw) > 0 {
-		varMappings, err = parseMappings(cfg.varRaw, false)
-		if err != nil {
-			fmt.Fprintf(stderr, "var parse error: %v\n", err)
-			return ExitRuntimeError
-		}
-	}
-
-	inputs := make(map[string]domain.ArtifactRef, len(inputMappings))
-	for name, path := range inputMappings {
-		inputs[name] = domain.ArtifactRef{Type: domain.ArtifactRefFile, URI: path}
-	}
 
 	llmClient, err := llm.NewOpenAICompatibleClient(llm.OpenAICompatibleConfig{
 		Timeout: defaults.LLMRequestTimeoutDefault,
@@ -135,28 +130,7 @@ func runCommand(args []string, stdout, stderr io.Writer) int {
 		validate.NewStandardValidator(cfg.schemaDir),
 	)
 
-	var modelOverride *domain.ExecutionTarget
-	if cfg.llmBaseURLSet || cfg.modelSet || cfg.temperatureSet || cfg.maxTokensSet || cfg.topPSet || cfg.apiKeyEnvSet || cfg.timeoutSet {
-		modelOverride = &domain.ExecutionTarget{
-			Endpoint:    cfg.llmBaseURL,
-			Model:       cfg.model,
-			Temperature: cfg.temperature,
-			MaxTokens:   cfg.maxTokens,
-			TopP:        cfg.topP,
-			APIKeyEnv:   cfg.apiKeyEnv,
-		}
-		if cfg.timeoutSet {
-			modelOverride.TimeoutSeconds = int(cfg.timeout.Seconds())
-		}
-	}
-
-	res, runErr := runner.Run(context.Background(), domain.RunRequest{
-		PromptID:  cfg.promptID,
-		ProfileID: cfg.profileID,
-		Inputs:    inputs,
-		Vars:      varMappings,
-		Execution: modelOverride,
-	})
+	res, runErr := runner.Run(context.Background(), req)
 	if runErr != nil {
 		fmt.Fprintf(stderr, "run error: %v\n", runErr)
 		return ExitRuntimeError
@@ -171,6 +145,47 @@ func runCommand(args []string, stdout, stderr io.Writer) int {
 	return determineExitCode(nil, res)
 }
 
+func renderCommand(args []string, stdout, stderr io.Writer) int {
+	cfg, err := parseRenderArgs(args)
+	if err != nil {
+		fmt.Fprintf(stderr, "render parse error: %v\n", err)
+		return ExitRuntimeError
+	}
+
+	req, err := buildRunRequestFromConfig(&cfg.runConfig)
+	if err != nil {
+		fmt.Fprintf(stderr, "render parse error: %v\n", err)
+		return ExitRuntimeError
+	}
+
+	runner := usecase.NewRunner(
+		promptdef.NewFilesystemRepository(cfg.promptDir),
+		profile.NewFilesystemRepository(cfg.profileDir),
+		artifactadapter.NewCompositeReader(),
+		prompt.NewGoRenderer(),
+		nil,
+		nil,
+	)
+
+	prepared, prepErr := runner.Prepare(context.Background(), req)
+	if prepErr != nil {
+		fmt.Fprintf(stderr, "render error: %v\n", prepErr)
+		return ExitRuntimeError
+	}
+
+	out, err := renderformat.FormatPreparedRun(prepared, cfg.outputFormat)
+	if err != nil {
+		fmt.Fprintf(stderr, "render format error: %v\n", err)
+		return ExitRuntimeError
+	}
+
+	if err := writeOutput(stdout, cfg.outputPath, out); err != nil {
+		fmt.Fprintf(stderr, "output write error: %v\n", err)
+		return ExitRuntimeError
+	}
+	return ExitOK
+}
+
 func serveCommand(args []string, stderr io.Writer) int {
 	cfg, err := parseServeArgs(args)
 	if err != nil {
@@ -215,60 +230,47 @@ func parseRunArgs(args []string) (*runConfig, error) {
 	fs := flag.NewFlagSet("run", flag.ContinueOnError)
 	fs.SetOutput(io.Discard)
 
-	fs.StringVar(&cfg.promptDir, "prompt-dir", "", "directory containing prompt definition YAML files")
-	fs.StringVar(&cfg.profileDir, "profile-dir", "", "directory containing execution profile YAML files")
-	fs.StringVar(&cfg.promptID, "prompt", "", "prompt ID to run")
-	fs.StringVar(&cfg.profileID, "profile", "", "optional execution profile ID; if omitted, prompt default_profile is used")
-	fs.Var(&cfg.inputRaw, "input", "input mapping(s): name=path (repeatable, comma-separated)")
-	fs.Var(&cfg.varRaw, "var", "variable mapping(s): name=value (repeatable, comma-separated)")
-	fs.StringVar(&cfg.outputPath, "out", "", "optional output file path")
-	fs.StringVar(&cfg.llmBaseURL, "llm-base-url", "", "OpenAI-compatible base URL including /v1")
-	fs.StringVar(&cfg.apiKeyEnv, "api-key-env", "", "environment variable name containing API key")
-	fs.StringVar(&cfg.model, "model", "", "model name")
-	fs.Float64Var(&cfg.temperature, "temperature", 0, "optional temperature override")
-	fs.IntVar(&cfg.maxTokens, "max-tokens", 0, "optional max tokens override")
-	fs.Float64Var(&cfg.topP, "top-p", 0, "optional top_p override")
+	registerExecutionRequestFlags(fs, cfg)
 	fs.StringVar(&cfg.schemaDir, "schema-dir", defaults.SchemaDirDefault, "base directory for validation schemas")
-	fs.DurationVar(&cfg.timeout, "timeout", defaults.LLMRequestTimeoutDefault, "LLM request timeout")
-	fs.StringVar(&cfg.promptID, "prompt-id", "", "deprecated alias for --prompt")
-	fs.StringVar(&cfg.profileID, "profile-id", "", "deprecated alias for --profile")
 
 	if err := fs.Parse(args); err != nil {
 		return nil, err
 	}
-	if fs.NArg() > 0 {
-		return nil, fmt.Errorf("unexpected positional args: %v", fs.Args())
+	if err := finalizeExecutionRequestConfig(fs, cfg); err != nil {
+		return nil, err
 	}
-
-	if strings.TrimSpace(cfg.promptDir) == "" {
-		return nil, errors.New("--prompt-dir is required")
-	}
-	if strings.TrimSpace(cfg.profileDir) == "" {
-		return nil, errors.New("--profile-dir is required")
-	}
-	if strings.TrimSpace(cfg.promptID) == "" {
-		return nil, errors.New("--prompt is required")
-	}
-	if len(cfg.inputRaw) == 0 {
-		return nil, errors.New("at least one --input is required")
-	}
-	cfg.promptDir = filepath.Clean(cfg.promptDir)
-	cfg.profileDir = filepath.Clean(cfg.profileDir)
 	cfg.schemaDir = filepath.Clean(cfg.schemaDir)
-	if cfg.outputPath != "" {
-		cfg.outputPath = filepath.Clean(cfg.outputPath)
-	}
-	cfg.llmBaseURLSet = flagWasSet(fs, "llm-base-url")
-	cfg.apiKeyEnvSet = flagWasSet(fs, "api-key-env")
-	cfg.modelSet = flagWasSet(fs, "model")
-	cfg.temperatureSet = flagWasSet(fs, "temperature")
-	cfg.maxTokensSet = flagWasSet(fs, "max-tokens")
-	cfg.topPSet = flagWasSet(fs, "top-p")
-	cfg.timeoutSet = flagWasSet(fs, "timeout")
 
 	return cfg, nil
 }
 
+func parseRenderArgs(args []string) (*renderConfig, error) {
+	cfg := &renderConfig{
+		outputFormat: renderformat.DefaultPreparedRunOutputFormat,
+	}
+	fs := flag.NewFlagSet("render", flag.ContinueOnError)
+	fs.SetOutput(io.Discard)
+
+	registerExecutionRequestFlags(fs, &cfg.runConfig)
+
+	var rawFormat string
+	fs.StringVar(&rawFormat, "format", string(renderformat.DefaultPreparedRunOutputFormat), "render output format (text|json)")
+
+	if err := fs.Parse(args); err != nil {
+		return nil, err
+	}
+	if err := finalizeExecutionRequestConfig(fs, &cfg.runConfig); err != nil {
+		return nil, err
+	}
+
+	format, err := renderformat.ParsePreparedRunOutputFormat(rawFormat)
+	if err != nil {
+		return nil, err
+	}
+	cfg.outputFormat = format
+	return cfg, nil
+}
+
 func parseServeArgs(args []string) (*serveConfig, error) {
 	cfg := &serveConfig{}
 	fs := flag.NewFlagSet("serve", flag.ContinueOnError)
@@ -299,6 +301,100 @@ func parseServeArgs(args []string) (*serveConfig, error) {
 	return cfg, nil
 }
 
+func registerExecutionRequestFlags(fs *flag.FlagSet, cfg *runConfig) {
+	fs.StringVar(&cfg.promptDir, "prompt-dir", "", "directory containing prompt definition YAML files")
+	fs.StringVar(&cfg.profileDir, "profile-dir", "", "directory containing execution profile YAML files")
+	fs.StringVar(&cfg.promptID, "prompt", "", "prompt ID to run")
+	fs.StringVar(&cfg.profileID, "profile", "", "optional execution profile ID; if omitted, prompt default_profile is used")
+	fs.Var(&cfg.inputRaw, "input", "input mapping(s): name=path (repeatable, comma-separated)")
+	fs.Var(&cfg.varRaw, "var", "variable mapping(s): name=value (repeatable, comma-separated)")
+	fs.StringVar(&cfg.outputPath, "out", "", "optional output file path")
+	fs.StringVar(&cfg.llmBaseURL, "llm-base-url", "", "OpenAI-compatible base URL including /v1")
+	fs.StringVar(&cfg.apiKeyEnv, "api-key-env", "", "environment variable name containing API key")
+	fs.StringVar(&cfg.model, "model", "", "model name")
+	fs.Float64Var(&cfg.temperature, "temperature", 0, "optional temperature override")
+	fs.IntVar(&cfg.maxTokens, "max-tokens", 0, "optional max tokens override")
+	fs.Float64Var(&cfg.topP, "top-p", 0, "optional top_p override")
+	fs.DurationVar(&cfg.timeout, "timeout", defaults.LLMRequestTimeoutDefault, "LLM request timeout")
+	fs.StringVar(&cfg.promptID, "prompt-id", "", "deprecated alias for --prompt")
+	fs.StringVar(&cfg.profileID, "profile-id", "", "deprecated alias for --profile")
+}
+
+func finalizeExecutionRequestConfig(fs *flag.FlagSet, cfg *runConfig) error {
+	if fs.NArg() > 0 {
+		return fmt.Errorf("unexpected positional args: %v", fs.Args())
+	}
+
+	if strings.TrimSpace(cfg.promptDir) == "" {
+		return errors.New("--prompt-dir is required")
+	}
+	if strings.TrimSpace(cfg.profileDir) == "" {
+		return errors.New("--profile-dir is required")
+	}
+	if strings.TrimSpace(cfg.promptID) == "" {
+		return errors.New("--prompt is required")
+	}
+	if len(cfg.inputRaw) == 0 {
+		return errors.New("at least one --input is required")
+	}
+	cfg.promptDir = filepath.Clean(cfg.promptDir)
+	cfg.profileDir = filepath.Clean(cfg.profileDir)
+	if cfg.outputPath != "" {
+		cfg.outputPath = filepath.Clean(cfg.outputPath)
+	}
+	cfg.llmBaseURLSet = flagWasSet(fs, "llm-base-url")
+	cfg.apiKeyEnvSet = flagWasSet(fs, "api-key-env")
+	cfg.modelSet = flagWasSet(fs, "model")
+	cfg.temperatureSet = flagWasSet(fs, "temperature")
+	cfg.maxTokensSet = flagWasSet(fs, "max-tokens")
+	cfg.topPSet = flagWasSet(fs, "top-p")
+	cfg.timeoutSet = flagWasSet(fs, "timeout")
+	return nil
+}
+
+func buildRunRequestFromConfig(cfg *runConfig) (domain.RunRequest, error) {
+	inputMappings, err := parseMappings(cfg.inputRaw, false)
+	if err != nil {
+		return domain.RunRequest{}, fmt.Errorf("input parse error: %w", err)
+	}
+
+	varMappings := map[string]string{}
+	if len(cfg.varRaw) > 0 {
+		varMappings, err = parseMappings(cfg.varRaw, false)
+		if err != nil {
+			return domain.RunRequest{}, fmt.Errorf("var parse error: %w", err)
+		}
+	}
+
+	inputs := make(map[string]domain.ArtifactRef, len(inputMappings))
+	for name, path := range inputMappings {
+		inputs[name] = domain.ArtifactRef{Type: domain.ArtifactRefFile, URI: path}
+	}
+
+	var modelOverride *domain.ExecutionTarget
+	if cfg.llmBaseURLSet || cfg.modelSet || cfg.temperatureSet || cfg.maxTokensSet || cfg.topPSet || cfg.apiKeyEnvSet || cfg.timeoutSet {
+		modelOverride = &domain.ExecutionTarget{
+			Endpoint:    cfg.llmBaseURL,
+			Model:       cfg.model,
+			Temperature: cfg.temperature,
+			MaxTokens:   cfg.maxTokens,
+			TopP:        cfg.topP,
+			APIKeyEnv:   cfg.apiKeyEnv,
+		}
+		if cfg.timeoutSet {
+			modelOverride.TimeoutSeconds = int(cfg.timeout.Seconds())
+		}
+	}
+
+	return domain.RunRequest{
+		PromptID:  cfg.promptID,
+		ProfileID: cfg.profileID,
+		Inputs:    inputs,
+		Vars:      varMappings,
+		Execution: modelOverride,
+	}, nil
+}
+
 func parseMappings(raw []string, allowEmptyValue bool) (map[string]string, error) {
 	out := make(map[string]string)
 	for _, entry := range raw {
@@ -385,7 +481,8 @@ func printSummary(stderr io.Writer, res *domain.RunResult) {
 }
 
 func printUsage(w io.Writer) {
-	fmt.Fprintln(w, "usage: scriptorium <run|serve> ...")
+	fmt.Fprintln(w, "usage: scriptorium <run|render|serve> ...")
 	fmt.Fprintln(w, "  run:   scriptorium run --prompt-dir DIR --profile-dir DIR --prompt ID --input name=path [--input ...] [--profile ID] [--llm-base-url URL] [--model NAME] [--api-key-env ENV] [--temperature N] [--max-tokens N] [--top-p N] [--var k=v] [--out path] [--timeout 10m]")
+	fmt.Fprintln(w, "  render: scriptorium render --prompt-dir DIR --profile-dir DIR --prompt ID --input name=path [--input ...] [--profile ID] [--llm-base-url URL] [--model NAME] [--api-key-env ENV] [--temperature N] [--max-tokens N] [--top-p N] [--var k=v] [--format text|json] [--out path] [--timeout 10m]")
 	fmt.Fprintf(w, "  serve: scriptorium serve --addr %s --prompt-dir DIR --profile-dir DIR [--schema-dir DIR]\n", defaults.HTTPAddrDefault)
 }
diff --git a/internal/adapter/cli/run_test.go b/internal/adapter/cli/run_test.go
index c3bc925..ad4cdc1 100644
--- a/internal/adapter/cli/run_test.go
+++ b/internal/adapter/cli/run_test.go
@@ -2,6 +2,7 @@ package cli
 
 import (
 	"bytes"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -16,6 +17,7 @@ import (
 
 	"gitea.maximumdirect.net/eric/scriptorium/internal/defaults"
 	"gitea.maximumdirect.net/eric/scriptorium/internal/domain"
+	renderformat "gitea.maximumdirect.net/eric/scriptorium/internal/format"
 )
 
 func TestParseMappingsSingleAndRepeated(t *testing.T) {
@@ -205,6 +207,65 @@ func TestParseRunArgsTimeout(t *testing.T) {
 	}
 }
 
+func TestParseRenderArgsDefaultsAndFormat(t *testing.T) {
+	cfg, err := parseRenderArgs([]string{
+		"--prompt-dir", "./prompts",
+		"--profile-dir", "./profiles",
+		"--prompt", "p",
+		"--input", "a=b",
+	})
+	if err != nil {
+		t.Fatalf("expected valid render args, got %v", err)
+	}
+	if cfg.outputFormat != renderformat.DefaultPreparedRunOutputFormat {
+		t.Fatalf("expected default render format %q, got %q", renderformat.DefaultPreparedRunOutputFormat, cfg.outputFormat)
+	}
+}
+
+func TestParseRenderArgsExplicitFormatsAndUnknown(t *testing.T) {
+	cfg, err := parseRenderArgs([]string{
+		"--prompt-dir", "./prompts",
+		"--profile-dir", "./profiles",
+		"--prompt", "p",
+		"--input", "a=b",
+		"--format", "text",
+	})
+	if err != nil {
+		t.Fatalf("expected valid text format, got %v", err)
+	}
+	if cfg.outputFormat != renderformat.PreparedRunFormatText {
+		t.Fatalf("expected text format, got %q", cfg.outputFormat)
+	}
+
+	cfg, err = parseRenderArgs([]string{
+		"--prompt-dir", "./prompts",
+		"--profile-dir", "./profiles",
+		"--prompt", "p",
+		"--input", "a=b",
+		"--format", "json",
+	})
+	if err != nil {
+		t.Fatalf("expected valid json format, got %v", err)
+	}
+	if cfg.outputFormat != renderformat.PreparedRunFormatJSON {
+		t.Fatalf("expected json format, got %q", cfg.outputFormat)
+	}
+
+	_, err = parseRenderArgs([]string{
+		"--prompt-dir", "./prompts",
+		"--profile-dir", "./profiles",
+		"--prompt", "p",
+		"--input", "a=b",
+		"--format", "yaml",
+	})
+	if err == nil {
+		t.Fatal("expected unknown format error")
+	}
+	if !strings.Contains(err.Error(), "unknown prepared run format") {
+		t.Fatalf("expected clear unknown format error, got %v", err)
+	}
+}
+
 func TestDetermineExitCode(t *testing.T) {
 	if got := determineExitCode(errors.New("boom"), nil); got != ExitRuntimeError {
 		t.Fatalf("expected runtime exit code, got %d", got)
@@ -247,6 +308,220 @@ func TestRunCommandVarsOptional(t *testing.T) {
 	}
 }
 
+func TestRenderCommandDefaultFormatTextIncludesPreparedDetailsAndNoSecrets(t *testing.T) {
+	const envName = "SCRIPTORIUM_RENDER_TEST_API_KEY"
+	const secret = "super-secret-render-key"
+	t.Setenv(envName, secret)
+
+	tmp := t.TempDir()
+	promptDir := filepath.Join(tmp, "prompts")
+	profileDir := filepath.Join(tmp, "profiles")
+	if err := os.MkdirAll(promptDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.MkdirAll(profileDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	inputPath := filepath.Join(tmp, "transcript.md")
+	if err := os.WriteFile(inputPath, []byte("hello transcript"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	writePromptFileWithTemplate(t, promptDir, "prompt.render", "local-default", "Date {{.session_date}} - Summarize: {{input \"transcript\"}}")
+	writeProfileFile(t, profileDir, "local-default", "http://127.0.0.1:1/v1", "profile-model")
+
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	code := renderCommand([]string{
+		"--prompt-dir", promptDir,
+		"--profile-dir", profileDir,
+		"--prompt", "prompt.render",
+		"--profile", "local-default",
+		"--input", "transcript=" + inputPath,
+		"--var", "session_date=2026-05-04",
+		"--llm-base-url", "http://override.local/v1",
+		"--model", "override-model",
+		"--temperature", "0.7",
+		"--max-tokens", "55",
+		"--top-p", "0.2",
+		"--timeout", "20s",
+		"--api-key-env", envName,
+	}, &stdout, &stderr)
+	if code != ExitOK {
+		t.Fatalf("expected ExitOK, got %d stderr=%q", code, stderr.String())
+	}
+	if stderr.Len() != 0 {
+		t.Fatalf("expected empty stderr on success, got %q", stderr.String())
+	}
+
+	out := stdout.String()
+	for _, want := range []string{
+		"prompt: prompt.render",
+		"selected_profile_id: local-default",
+		"endpoint: http://override.local/v1",
+		"model: override-model",
+		"temperature: 0.7",
+		"max_tokens: 55",
+		"top_p: 0.2",
+		"timeout_seconds: 20",
+		"api_key_env: " + envName,
+		"rendered_prompt_hash:",
+		"messages:",
+		"Date 2026-05-04",
+		"Summarize:",
+		"hello transcript",
+	} {
+		if !strings.Contains(out, want) {
+			t.Fatalf("expected render text output to include %q, got:\n%s", want, out)
+		}
+	}
+	if strings.Contains(out, secret) {
+		t.Fatalf("render output unexpectedly contained secret api key value: %s", out)
+	}
+}
+
+func TestRenderCommandExplicitTextFormatWorks(t *testing.T) {
+	tmp := t.TempDir()
+	promptDir := filepath.Join(tmp, "prompts")
+	profileDir := filepath.Join(tmp, "profiles")
+	if err := os.MkdirAll(promptDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.MkdirAll(profileDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	inputPath := filepath.Join(tmp, "transcript.md")
+	if err := os.WriteFile(inputPath, []byte("hello transcript"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	writePromptFile(t, promptDir, "prompt.render", "local-default")
+	writeProfileFile(t, profileDir, "local-default", "http://127.0.0.1:1/v1", "profile-model")
+
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	code := renderCommand([]string{
+		"--prompt-dir", promptDir,
+		"--profile-dir", profileDir,
+		"--prompt", "prompt.render",
+		"--input", "transcript=" + inputPath,
+		"--format", "text",
+	}, &stdout, &stderr)
+	if code != ExitOK {
+		t.Fatalf("expected ExitOK, got %d stderr=%q", code, stderr.String())
+	}
+	if !strings.Contains(stdout.String(), "prompt: prompt.render") {
+		t.Fatalf("expected text output for explicit --format text, got %q", stdout.String())
+	}
+}
+
+func TestRenderCommandExplicitJSONFormatOutputsValidJSON(t *testing.T) {
+	tmp := t.TempDir()
+	promptDir := filepath.Join(tmp, "prompts")
+	profileDir := filepath.Join(tmp, "profiles")
+	if err := os.MkdirAll(promptDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.MkdirAll(profileDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	inputPath := filepath.Join(tmp, "transcript.md")
+	if err := os.WriteFile(inputPath, []byte("hello transcript"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	writePromptFile(t, promptDir, "prompt.render", "local-default")
+	writeProfileFile(t, profileDir, "local-default", "http://127.0.0.1:1/v1", "profile-model")
+
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	code := renderCommand([]string{
+		"--prompt-dir", promptDir,
+		"--profile-dir", profileDir,
+		"--prompt", "prompt.render",
+		"--input", "transcript=" + inputPath,
+		"--format", "json",
+	}, &stdout, &stderr)
+	if code != ExitOK {
+		t.Fatalf("expected ExitOK, got %d stderr=%q", code, stderr.String())
+	}
+
+	var payload map[string]any
+	if err := json.Unmarshal(stdout.Bytes(), &payload); err != nil {
+		t.Fatalf("expected valid json output, got %v\nbody=%s", err, stdout.String())
+	}
+	if payload["prompt_id"] != "prompt.render" {
+		t.Fatalf("expected prompt_id, got %#v", payload["prompt_id"])
+	}
+	if payload["selected_profile_id"] != "local-default" {
+		t.Fatalf("expected selected_profile_id, got %#v", payload["selected_profile_id"])
+	}
+	if _, ok := payload["messages"]; !ok {
+		t.Fatalf("expected messages in render json output, got %#v", payload)
+	}
+}
+
+func TestRenderCommandUnknownFormatFailsClearly(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	code := renderCommand([]string{
+		"--prompt-dir", "./prompts",
+		"--profile-dir", "./profiles",
+		"--prompt", "p",
+		"--input", "transcript=./x.md",
+		"--format", "yaml",
+	}, &stdout, &stderr)
+	if code != ExitRuntimeError {
+		t.Fatalf("expected ExitRuntimeError, got %d", code)
+	}
+	if !strings.Contains(stderr.String(), "render parse error") || !strings.Contains(stderr.String(), "unknown prepared run format") {
+		t.Fatalf("expected clear unknown-format parse error, got %q", stderr.String())
+	}
+}
+
+func TestRenderCommandOutWritesToFile(t *testing.T) {
+	tmp := t.TempDir()
+	promptDir := filepath.Join(tmp, "prompts")
+	profileDir := filepath.Join(tmp, "profiles")
+	if err := os.MkdirAll(promptDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.MkdirAll(profileDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	inputPath := filepath.Join(tmp, "transcript.md")
+	if err := os.WriteFile(inputPath, []byte("hello transcript"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	outPath := filepath.Join(tmp, "render.txt")
+
+	writePromptFile(t, promptDir, "prompt.render", "local-default")
+	writeProfileFile(t, profileDir, "local-default", "http://127.0.0.1:1/v1", "profile-model")
+
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	code := renderCommand([]string{
+		"--prompt-dir", promptDir,
+		"--profile-dir", profileDir,
+		"--prompt", "prompt.render",
+		"--input", "transcript=" + inputPath,
+		"--out", outPath,
+	}, &stdout, &stderr)
+	if code != ExitOK {
+		t.Fatalf("expected ExitOK, got %d stderr=%q", code, stderr.String())
+	}
+	if stdout.Len() != 0 {
+		t.Fatalf("expected empty stdout when --out is set, got %q", stdout.String())
+	}
+	out, err := os.ReadFile(outPath)
+	if err != nil {
+		t.Fatalf("failed reading render output file: %v", err)
+	}
+	if !strings.Contains(string(out), "prompt: prompt.render") {
+		t.Fatalf("expected render output in file, got %q", string(out))
+	}
+}
+
 func TestRunCommandPromptDefaultProfileWorksThroughCLIPath(t *testing.T) {
 	tmp := t.TempDir()
 	promptDir := filepath.Join(tmp, "prompts")
@@ -425,6 +700,11 @@ func TestWriteOutputAndSummaryUseSeparateWriters(t *testing.T) {
 }
 
 func writePromptFile(t *testing.T, dir, id, defaultProfile string) {
+	t.Helper()
+	writePromptFileWithTemplate(t, dir, id, defaultProfile, "Summarize: {{input \"transcript\"}}")
+}
+
+func writePromptFileWithTemplate(t *testing.T, dir, id, defaultProfile, templateContent string) {
 	t.Helper()
 	data := fmt.Sprintf(`id: %s
 version: "1.0.0"
@@ -434,12 +714,12 @@ inputs:
     required: true
 messages:
   - role: user
-    content: "Summarize: {{input \"transcript\"}}"
+    content: %q
 output:
   format: text
   validation_mode: none
   repair_attempts: 0
-`, id, defaultProfile)
+`, id, defaultProfile, templateContent)
 	if err := os.WriteFile(filepath.Join(dir, id+".yaml"), []byte(data), 0o644); err != nil {
 		t.Fatalf("failed to write prompt fixture: %v", err)
 	}