fix: enable Gemini file writing by passing --yolo and -p flags

GeminiRunner.buildArgs was missing --yolo (auto-approve all tools)
so the gemini CLI only registered 3 tools (read_file, write_todos,
cli_help) and write_file was not available. Agents that needed to
create files silently failed (exit 0, no files written).

Also switch instructions from bare positional arg to -p flag, which
is required for non-interactive headless mode.

Update preamble tests to match file-based summary approach
(CLAUDOMATOR_SUMMARY_FILE) kept from the merge conflict resolution.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

3 files changed, 58 insertions, 16 deletions

diff --git a/internal/executor/gemini.go b/internal/executor/gemini.go
index 956d8b5..c30cd66 100644
--- a/internal/executor/gemini.go
+++ b/internal/executor/gemini.go
@@ -169,8 +169,9 @@ func (r *GeminiRunner) buildArgs(t *task.Task, e *storage.Execution, questionFil
 	}
 
 	args := []string{
-		instructions,
+		"-p", instructions,
 		"--output-format", "stream-json",
+		"--yolo", // auto-approve all tools (equivalent to Claude's bypassPermissions)
 	}
 
 	// Note: Gemini CLI flags might differ from Claude CLI.
diff --git a/internal/executor/gemini_test.go b/internal/executor/gemini_test.go
index 363f0e9..073525c 100644
--- a/internal/executor/gemini_test.go
+++ b/internal/executor/gemini_test.go
@@ -24,9 +24,9 @@ func TestGeminiRunner_BuildArgs_BasicTask(t *testing.T) {
 
 	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")
 
-	// Gemini CLI: instructions is the first positional arg
-	if len(args) < 1 || args[0] != "fix the bug" {
-		t.Errorf("expected instructions as first arg, got: %v", args)
+	// Gemini CLI: instructions passed via -p for non-interactive mode
+	if len(args) < 2 || args[0] != "-p" || args[1] != "fix the bug" {
+		t.Errorf("expected -p <instructions> as first args, got: %v", args)
 	}
 
 	argMap := make(map[string]bool)
@@ -52,17 +52,60 @@ func TestGeminiRunner_BuildArgs_PreamblePrepended(t *testing.T) {
 
 	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")
 
-	if len(args) < 1 {
-		t.Fatalf("expected at least 1 arg, got: %v", args)
+	if len(args) < 2 || args[0] != "-p" {
+		t.Fatalf("expected -p <instructions> as first args, got: %v", args)
 	}
-	if !strings.HasPrefix(args[0], planningPreamble) {
+	if !strings.HasPrefix(args[1], planningPreamble) {
 		t.Errorf("instructions should start with planning preamble")
 	}
-	if !strings.HasSuffix(args[0], "fix the bug") {
+	if !strings.HasSuffix(args[1], "fix the bug") {
 		t.Errorf("instructions should end with original instructions")
 	}
 }
 
+func TestGeminiRunner_BuildArgs_IncludesYolo(t *testing.T) {
+	r := &GeminiRunner{}
+	tk := &task.Task{
+		Agent: task.AgentConfig{
+			Type:         "gemini",
+			Instructions: "write a doc",
+			SkipPlanning: true,
+		},
+	}
+	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")
+	argMap := make(map[string]bool)
+	for _, a := range args {
+		argMap[a] = true
+	}
+	if !argMap["--yolo"] {
+		t.Errorf("expected --yolo in gemini args (enables all tools); got: %v", args)
+	}
+}
+
+func TestGeminiRunner_BuildArgs_IncludesPromptFlag(t *testing.T) {
+	r := &GeminiRunner{}
+	tk := &task.Task{
+		Agent: task.AgentConfig{
+			Type:         "gemini",
+			Instructions: "do the thing",
+			SkipPlanning: true,
+		},
+	}
+	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")
+	// Instructions must be passed via -p/--prompt for non-interactive headless mode,
+	// not as a bare positional (which starts interactive mode).
+	found := false
+	for i, a := range args {
+		if (a == "-p" || a == "--prompt") && i+1 < len(args) && args[i+1] == "do the thing" {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Errorf("expected instructions passed via -p/--prompt flag; got: %v", args)
+	}
+}
+
 func TestGeminiRunner_Run_InaccessibleProjectDir_ReturnsError(t *testing.T) {
 	r := &GeminiRunner{
 		BinaryPath: "true", // would succeed if it ran
diff --git a/internal/executor/preamble_test.go b/internal/executor/preamble_test.go
index 448ad3a..984f786 100644
--- a/internal/executor/preamble_test.go
+++ b/internal/executor/preamble_test.go
@@ -11,16 +11,14 @@ func TestPlanningPreamble_ContainsFinalSummarySection(t *testing.T) {
 	}
 }
 
-func TestPlanningPreamble_SummaryRequiresMarkdownHeader(t *testing.T) {
-	if !strings.Contains(planningPreamble, `Start it with "## Summary"`) {
-		t.Error("planningPreamble does not instruct agent to start summary with '## Summary'")
+func TestPlanningPreamble_SummaryUsesFileEnvVar(t *testing.T) {
+	if !strings.Contains(planningPreamble, "CLAUDOMATOR_SUMMARY_FILE") {
+		t.Error("planningPreamble should instruct agent to write summary to $CLAUDOMATOR_SUMMARY_FILE")
 	}
 }
 
-func TestPlanningPreamble_SummaryDescribesRequiredContent(t *testing.T) {
-	for _, phrase := range []string{"What was accomplished", "Key decisions made", "Any issues or follow-ups"} {
-		if !strings.Contains(planningPreamble, phrase) {
-			t.Errorf("planningPreamble missing required summary content description: %q", phrase)
-		}
+func TestPlanningPreamble_SummaryInstructsEchoToFile(t *testing.T) {
+	if !strings.Contains(planningPreamble, `"$CLAUDOMATOR_SUMMARY_FILE"`) {
+		t.Error("planningPreamble should show example of writing to $CLAUDOMATOR_SUMMARY_FILE via echo")
 	}
 }