fix(#2869): inject FULLSEND_OUTPUT_SCHEMA into validation script env

internal/cli/run.go

@@ -1106,12 +1106,7 @@ func runAgent(ctx context.Context, agentName, fullsendDir, outputBase, targetRep
 		printer.StepStart("Running validation: " + h.ValidationLoop.Script)
 		valCmd := exec.Command(h.ValidationLoop.Script)
 		valCmd.Dir = iterDir
-		valCmd.Env = append(os.Environ(),
-			append(envToList(h.RunnerEnv),
-				fmt.Sprintf("TARGET_REPO_DIR=%s", hostRepositoryDir),
-				fmt.Sprintf("FULLSEND_RUN_DIR=%s", runDir),
-			)...,
-		)
+		valCmd.Env = append(os.Environ(), validationEnv(h, hostRepositoryDir, runDir)...)
 		valOut, valErr := valCmd.CombinedOutput()
 
 		if valErr == nil {
@@ -1698,6 +1693,21 @@ func childScriptEnv(runnerEnv map[string]string, traceparent string) []string {
 	return env
 }
 
+// validationEnv builds the extra environment entries for the validation
+// script. It includes RunnerEnv, TARGET_REPO_DIR, FULLSEND_RUN_DIR, and —
+// when the harness specifies a validation_loop.schema — FULLSEND_OUTPUT_SCHEMA
+// pointing to the host-side cached schema path.
+func validationEnv(h *harness.Harness, hostRepoDir, runDir string) []string {
+	env := append(envToList(h.RunnerEnv),
+		fmt.Sprintf("TARGET_REPO_DIR=%s", hostRepoDir),
+		fmt.Sprintf("FULLSEND_RUN_DIR=%s", runDir),
+	)
+	if h.ValidationLoop != nil && h.ValidationLoop.Schema != "" {
+		env = append(env, fmt.Sprintf("FULLSEND_OUTPUT_SCHEMA=%s", h.ValidationLoop.Schema))
+	}
+	return env
+}
+
 func envToList(env map[string]string) []string {
 	keys := make([]string, 0, len(env))
 	for k := range env {

internal/cli/run_test.go

@@ -1393,6 +1393,46 @@ func TestValidationFailMessage_TrimsOutput(t *testing.T) {
 	assert.Equal(t, "some output", msg)
 }
 
+func TestValidationEnv_IncludesSchemaWhenSet(t *testing.T) {
+	h := &harness.Harness{
+		RunnerEnv: map[string]string{"FOO": "bar"},
+		ValidationLoop: &harness.ValidationLoop{
+			Script: "scripts/validate.sh",
+			Schema: "/tmp/test-schema.json",
+		},
+	}
+	env := validationEnv(h, "/repo", "/run")
+	assert.Contains(t, env, "FULLSEND_OUTPUT_SCHEMA=/tmp/test-schema.json")
+	assert.Contains(t, env, "TARGET_REPO_DIR=/repo")
+	assert.Contains(t, env, "FULLSEND_RUN_DIR=/run")
+	assert.Contains(t, env, "FOO=bar")
+}
+
+func TestValidationEnv_OmitsSchemaWhenEmpty(t *testing.T) {
+	h := &harness.Harness{
+		RunnerEnv: map[string]string{"FOO": "bar"},
+		ValidationLoop: &harness.ValidationLoop{
+			Script: "scripts/validate.sh",
+		},
+	}
+	env := validationEnv(h, "/repo", "/run")
+	for _, e := range env {
+		assert.False(t, strings.HasPrefix(e, "FULLSEND_OUTPUT_SCHEMA="),
+			"FULLSEND_OUTPUT_SCHEMA should not be set when Schema is empty")
+	}
+}
+
+func TestValidationEnv_OmitsSchemaWhenNoValidationLoop(t *testing.T) {
+	h := &harness.Harness{
+		RunnerEnv: map[string]string{"FOO": "bar"},
+	}
+	env := validationEnv(h, "/repo", "/run")
+	for _, e := range env {
+		assert.False(t, strings.HasPrefix(e, "FULLSEND_OUTPUT_SCHEMA="),
+			"FULLSEND_OUTPUT_SCHEMA should not be set when ValidationLoop is nil")
+	}
+}
+
 func TestOpenTeeReader_EmptyPath(t *testing.T) {
 	src := strings.NewReader("hello")
 	printer := ui.New(io.Discard)