Fix Windows 32KB command-line limit for agent prompts

cmd/roborev/main.go

@@ -3034,6 +3034,7 @@ func checkAgentsCmd() *cobra.Command {
 	var (
 		timeoutSecs int
 		agentFilter string
+		largePrompt bool
 	)
 
 	cmd := &cobra.Command{
@@ -3045,15 +3046,20 @@ For each agent found on PATH, runs a short smoke-test prompt with a timeout
 to verify the agent is actually functional.
 
 Examples:
-  roborev check-agents              # Check all agents
-  roborev check-agents --agent codex  # Check only codex
-  roborev check-agents --timeout 30   # 30 second timeout per agent`,
+  roborev check-agents                  # Check all agents
+  roborev check-agents --agent codex    # Check only codex
+  roborev check-agents --timeout 30     # 30 second timeout per agent
+  roborev check-agents --large-prompt   # Test with 33KB+ prompt (Windows limit check)`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			names := agent.Available()
 			sort.Strings(names)
 
 			timeout := time.Duration(timeoutSecs) * time.Second
 			smokePrompt := "Respond with exactly: OK"
+			if largePrompt {
+				smokePrompt = "Respond with exactly: OK\n" +
+					strings.Repeat("// padding line\n", 2200)
+			}
 
 			// Use current directory as repo path for the smoke test
 			repoPath, err := os.Getwd()
@@ -3124,6 +3130,8 @@ Examples:
 	cmd.SilenceUsage = true
 	cmd.Flags().IntVar(&timeoutSecs, "timeout", 60, "timeout in seconds per agent")
 	cmd.Flags().StringVar(&agentFilter, "agent", "", "check only this agent")
+	cmd.Flags().BoolVar(&largePrompt, "large-prompt", false,
+		"use a 33KB+ prompt to test Windows command-line limits")
 
 	return cmd
 }

internal/agent/claude.go

@@ -11,6 +11,7 @@
 	"os/exec"
 	"strings"
 	"sync"
+	"time"
 )
 
 // ClaudeAgent runs code reviews using Claude Code CLI
@@ -133,6 +134,7 @@
 
 	cmd := exec.CommandContext(ctx, a.Command, args...)
 	cmd.Dir = repoPath
+	cmd.WaitDelay = 5 * time.Second
 
 	// Handle API key: use configured key if set, otherwise filter out env var
 	// to ensure Claude uses subscription auth instead of unexpected API charges
@@ -207,7 +209,7 @@
 		if line != "" {
 			// Stream raw line to the writer for progress visibility
 			if sw := newSyncWriter(output); sw != nil {
 				sw.Write([]byte(line + "\n"))
 			}
 
 			var msg claudeStreamMessage

internal/agent/codex.go

@@ -11,6 +11,7 @@
 	"os/exec"
 	"strings"
 	"sync"
+	"time"
 )
 
 // CodexAgent runs code reviews using the Codex CLI
@@ -195,6 +196,7 @@
 
 	cmd := exec.CommandContext(ctx, a.Command, args...)
 	cmd.Dir = repoPath
+	cmd.WaitDelay = 5 * time.Second
 
 	// Pipe prompt via stdin to avoid command line length limits on Windows.
 	// Windows has a ~32KB limit on command line arguments, which large diffs easily exceed.
@@ -310,7 +312,7 @@
 		if trimmed != "" {
 			// Stream raw line to the writer for progress visibility
 			if sw != nil {
 				sw.Write([]byte(trimmed + "\n"))
 			}
 
 			var ev codexEvent

internal/agent/copilot.go

@@ -73,19 +73,17 @@ func (a *CopilotAgent) CommandLine() string {
 	if a.Model != "" {
 		args = append(args, "--model", a.Model)
 	}
-	args = append(args, "--prompt")
 	return a.Command + " " + strings.Join(args, " ")
 }
 
 func (a *CopilotAgent) Review(ctx context.Context, repoPath, commitSHA, prompt string, output io.Writer) (string, error) {
-	// Use copilot with --prompt for non-interactive mode
 	args := []string{}
 	if a.Model != "" {
 		args = append(args, "--model", a.Model)
 	}
-	args = append(args, "--prompt", prompt)
 
 	cmd := exec.CommandContext(ctx, a.Command, args...)
+	cmd.Stdin = strings.NewReader(prompt)
 	cmd.Dir = repoPath
 
 	var stdout, stderr bytes.Buffer

internal/agent/cursor.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/exec"
 	"strings"
+	"time"
 )
 
 // CursorAgent runs code reviews using the Cursor agent CLI
@@ -83,7 +84,7 @@ func (a *CursorAgent) CommandLine() string {
 	return a.Command + " " + strings.Join(args, " ")
 }
 
-func (a *CursorAgent) buildArgs(agenticMode bool, prompt string) []string {
+func (a *CursorAgent) buildArgs(agenticMode bool) []string {
 	// -p enables non-interactive print mode (like Claude Code's -p flag)
 	args := []string{"-p", "--output-format", "stream-json"}
 
@@ -100,20 +101,19 @@ func (a *CursorAgent) buildArgs(agenticMode bool, prompt string) []string {
 		args = append(args, "--mode", "plan")
 	}
 
-	// Prompt is a positional argument for the agent CLI
-	args = append(args, prompt)
-
 	return args
 }
 
 func (a *CursorAgent) Review(ctx context.Context, repoPath, commitSHA, prompt string, output io.Writer) (string, error) {
 	agenticMode := a.Agentic || AllowUnsafeAgents()
 
-	args := a.buildArgs(agenticMode, prompt)
+	args := a.buildArgs(agenticMode)
 
 	cmd := exec.CommandContext(ctx, a.Command, args...)
 	cmd.Dir = repoPath
 	cmd.Env = os.Environ()
+	cmd.WaitDelay = 5 * time.Second
+	cmd.Stdin = strings.NewReader(prompt)
 
 	var stderr bytes.Buffer
 	stdoutPipe, err := cmd.StdoutPipe()

internal/agent/cursor_test.go

@@ -10,7 +10,7 @@ func TestCursorBuildArgs(t *testing.T) {
 	a := NewCursorAgent("agent")
 
 	// Non-agentic mode (review): --mode plan, no --force, default model "auto"
-	args := a.buildArgs(false, "review this")
+	args := a.buildArgs(false)
 	assertContainsArg(t, args, "-p")
 	assertContainsArg(t, args, "--output-format")
 	assertContainsArg(t, args, "stream-json")
@@ -19,26 +19,19 @@ func TestCursorBuildArgs(t *testing.T) {
 	assertContainsArg(t, args, "--mode")
 	assertContainsArg(t, args, "plan")
 	assertNotContainsArg(t, args, "--force")
-	// Prompt should be the last arg
-	if args[len(args)-1] != "review this" {
-		t.Errorf("expected prompt as last arg, got %q", args[len(args)-1])
-	}
 
 	// Agentic mode: --force, no --mode plan
-	args = a.buildArgs(true, "fix this")
+	args = a.buildArgs(true)
 	assertContainsArg(t, args, "--force")
 	assertNotContainsArg(t, args, "--mode")
 	assertNotContainsArg(t, args, "plan")
-	if args[len(args)-1] != "fix this" {
-		t.Errorf("expected prompt as last arg, got %q", args[len(args)-1])
-	}
 }
 
 func TestCursorBuildArgsWithModel(t *testing.T) {
 	a := NewCursorAgent("agent")
 	a = a.WithModel("gpt-5.2-codex-high").(*CursorAgent)
 
-	args := a.buildArgs(false, "test")
+	args := a.buildArgs(false)
 	assertContainsArg(t, args, "--model")
 	assertContainsArg(t, args, "gpt-5.2-codex-high")
 }

internal/agent/droid.go

@@ -77,7 +77,7 @@ func (a *DroidAgent) CommandLine() string {
 	return a.Command + " " + strings.Join(args, " ")
 }
 
-func (a *DroidAgent) buildArgs(prompt string, agenticMode bool) []string {
+func (a *DroidAgent) buildArgs(agenticMode bool) []string {
 	args := []string{"exec"}
 
 	// Set autonomy level based on agentic mode
@@ -92,21 +92,18 @@ func (a *DroidAgent) buildArgs(prompt string, agenticMode bool) []string {
 		args = append(args, "--reasoning-effort", effort)
 	}
 
-	// Add -- to stop flag parsing, then the prompt as the final argument
-	// This prevents prompts starting with "-" from being parsed as flags
-	args = append(args, "--", prompt)
-
 	return args
 }
 
 func (a *DroidAgent) Review(ctx context.Context, repoPath, commitSHA, prompt string, output io.Writer) (string, error) {
 	// Use agentic mode if either per-job setting or global setting enables it
 	agenticMode := a.Agentic || AllowUnsafeAgents()
 
-	args := a.buildArgs(prompt, agenticMode)
+	args := a.buildArgs(agenticMode)
 
 	cmd := exec.CommandContext(ctx, a.Command, args...)
 	cmd.Dir = repoPath
+	cmd.Stdin = strings.NewReader(prompt)
 
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout = &stdout

internal/agent/droid_test.go

@@ -12,31 +12,31 @@ func TestDroidBuildArgsAgenticMode(t *testing.T) {
 	a := NewDroidAgent("droid")
 
 	// Test non-agentic mode (--auto low)
-	args := a.buildArgs("prompt", false)
+	args := a.buildArgs(false)
 	assertContainsArg(t, args, "low")
 	assertNotContainsArg(t, args, "medium")
 
 	// Test agentic mode (--auto medium)
-	args = a.buildArgs("prompt", true)
+	args = a.buildArgs(true)
 	assertContainsArg(t, args, "medium")
 }
 
 func TestDroidBuildArgsReasoningEffort(t *testing.T) {
 	// Test thorough reasoning
 	a := NewDroidAgent("droid").WithReasoning(ReasoningThorough).(*DroidAgent)
-	args := a.buildArgs("prompt", false)
+	args := a.buildArgs(false)
 	assertContainsArg(t, args, "--reasoning-effort")
 	assertContainsArg(t, args, "high")
 
 	// Test fast reasoning
 	a = NewDroidAgent("droid").WithReasoning(ReasoningFast).(*DroidAgent)
-	args = a.buildArgs("prompt", false)
+	args = a.buildArgs(false)
 	assertContainsArg(t, args, "--reasoning-effort")
 	assertContainsArg(t, args, "low")
 
 	// Test standard reasoning (no flag)
 	a = NewDroidAgent("droid").WithReasoning(ReasoningStandard).(*DroidAgent)
-	args = a.buildArgs("prompt", false)
+	args = a.buildArgs(false)
 	assertNotContainsArg(t, args, "--reasoning-effort")
 }
 
@@ -121,21 +121,6 @@ func TestDroidReviewWithProgress(t *testing.T) {
 	}
 }
 
-func TestDroidBuildArgsPromptWithDash(t *testing.T) {
-	a := NewDroidAgent("droid")
-
-	prompt := "-o /tmp/malicious --auto high"
-	args := a.buildArgs(prompt, false)
-
-	// Verify "--" appears before the prompt
-	assertArgsOrder(t, args, "--", prompt)
-
-	// Verify the prompt is passed exactly as last arg
-	if args[len(args)-1] != prompt {
-		t.Fatalf("expected prompt as last arg, got %v", args)
-	}
-}
-
 func TestDroidReviewAgenticModeFromGlobal(t *testing.T) {
 	withUnsafeAgents(t, true)
 

internal/agent/gemini.go

@@ -10,6 +10,7 @@ import (
 	"io"
 	"os/exec"
 	"strings"
+	"time"
 )
 
 // errNoStreamJSON indicates no valid stream-json events were parsed.
@@ -116,6 +117,7 @@ func (a *GeminiAgent) Review(ctx context.Context, repoPath, commitSHA, prompt st
 
 	cmd := exec.CommandContext(ctx, a.Command, args...)
 	cmd.Dir = repoPath
+	cmd.WaitDelay = 5 * time.Second
 
 	// Pipe prompt via stdin
 	cmd.Stdin = strings.NewReader(prompt)

internal/agent/opencode.go

@@ -127,10 +127,10 @@ func (a *OpenCodeAgent) Review(ctx context.Context, repoPath, commitSHA, prompt
 	if a.Model != "" {
 		args = append(args, "--model", a.Model)
 	}
-	args = append(args, prompt)
 
 	cmd := exec.CommandContext(ctx, a.Command, args...)
 	cmd.Dir = repoPath
+	cmd.Stdin = strings.NewReader(prompt)
 
 	var stdout, stderr bytes.Buffer
 	if sw := newSyncWriter(output); sw != nil {

internal/daemon/ci_poller.go

@@ -1155,8 +1155,9 @@ func (p *CIPoller) postPRComment(ghRepo string, prNumber int, body string) error
 	cmd := exec.CommandContext(ctx, "gh", "pr", "comment",
 		"--repo", ghRepo,
 		fmt.Sprintf("%d", prNumber),
-		"--body", body,
+		"--body-file", "-",
 	)
+	cmd.Stdin = strings.NewReader(body)
 	if env := p.ghEnvForRepo(ghRepo); env != nil {
 		cmd.Env = env
 	}