Add harness user-agent dimension for omnigent meta-harness

Detect the OMNIGENT environment variable and report harness/omnigent as
an independent user-agent dimension, parallel to agent detection. This
lets the platform see both the meta-harness (omnigent) and the underlying
coding agent (e.g. claude-code) in the same request.

Co-authored-by: Isaac
Signed-off-by: simon <simon.faltum@databricks.com>

Author: simonfaltum

NEXT_CHANGELOG.md

@@ -6,6 +6,8 @@
 
 ### New Features and Improvements
 
+* Added a `harness` user-agent dimension that reports the omnigent meta-harness (detected via the `OMNIGENT` environment variable) independently of agent detection.
+
 ### Bug Fixes
 
 ### Documentation

config/api_client.go

@@ -74,6 +74,17 @@ func HTTPClientConfigFromConfig(cfg *Config) (httpclient.ClientConfig, error) {
 			*r = *r.WithContext(ctx) // replace request
 			return nil
 		},
+		func(r *http.Request) error {
+			// Detect if we are running inside a known agent meta-harness.
+			provider := useragent.HarnessProvider()
+			if provider == "" {
+				return nil
+			}
+			// Add the detected harness to the user agent.
+			ctx := useragent.InContext(r.Context(), useragent.HarnessKey, provider)
+			*r = *r.WithContext(ctx) // replace request
+			return nil
+		},
 	}
 
 	return httpclient.ClientConfig{

useragent/harness.go

@@ -0,0 +1,53 @@
+package useragent
+
+import (
+	"os"
+	"sync"
+)
+
+// knownHarness describes a meta-harness that orchestrates AI agents (not itself
+// an agent). Detected if envVar is set (any value, including empty, counts).
+type knownHarness struct {
+	envVar  string
+	product string
+}
+
+// listKnownHarnesses returns the canonical list of agent meta-harnesses.
+// Keep in sync with databricks-sdk-py and databricks-sdk-java.
+func listKnownHarnesses() []knownHarness {
+	return []knownHarness{
+		{envVar: "OMNIGENT", product: "omnigent"}, // https://github.com/omnigent-ai/omnigent
+	}
+}
+
+// lookupHarnessProvider returns the matched harness product, "multiple" if more
+// than one matched, or "" if none matched.
+func lookupHarnessProvider() string {
+	var matches []string
+	for _, h := range listKnownHarnesses() {
+		if _, ok := os.LookupEnv(h.envVar); ok {
+			matches = append(matches, h.product)
+		}
+	}
+	switch len(matches) {
+	case 1:
+		return matches[0]
+	case 0:
+		return ""
+	default:
+		return "multiple"
+	}
+}
+
+var (
+	harnessOnce sync.Once
+	harnessName string
+)
+
+// HarnessProvider returns the detected meta-harness name, cached for the process lifetime.
+func HarnessProvider() string {
+	harnessOnce.Do(func() {
+		harnessName = lookupHarnessProvider()
+	})
+	return harnessName
+}

useragent/harness_test.go

@@ -0,0 +1,66 @@
+package useragent
+
+import (
+	"testing"
+
+	"github.com/databricks/databricks-sdk-go/internal/env"
+)
+
+func TestLookupHarnessProvider(t *testing.T) {
+	tests := []struct {
+		name   string
+		envs   map[string]string
+		expect string
+	}{
+		{
+			name:   "no harness",
+			envs:   nil,
+			expect: "",
+		},
+		{
+			name:   "omnigent",
+			envs:   map[string]string{"OMNIGENT": "1"},
+			expect: "omnigent",
+		},
+		{
+			name:   "omnigent empty value still counts as set",
+			envs:   map[string]string{"OMNIGENT": ""},
+			expect: "omnigent",
+		},
+		{
+			name:   "agent env var does not affect harness",
+			envs:   map[string]string{"CLAUDECODE": "1"},
+			expect: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			env.CleanupEnvironment(t)
+			ClearCache()
+			for k, v := range tt.envs {
+				t.Setenv(k, v)
+			}
+			got := lookupHarnessProvider()
+			if got != tt.expect {
+				t.Errorf("lookupHarnessProvider() = %q, want %q", got, tt.expect)
+			}
+		})
+	}
+}
+
+func TestHarnessProviderCached(t *testing.T) {
+	env.CleanupEnvironment(t)
+	ClearCache()
+	t.Setenv("OMNIGENT", "1")
+	got := HarnessProvider()
+	if got != "omnigent" {
+		t.Errorf("HarnessProvider() = %q, want %q", got, "omnigent")
+	}
+	// Change env after caching. Cached result should persist.
+	t.Setenv("OMNIGENT", "")
+	got = HarnessProvider()
+	if got != "omnigent" {
+		t.Errorf("HarnessProvider() after cache = %q, want %q", got, "omnigent")
+	}
+}

useragent/runtime.go

@@ -13,6 +13,7 @@ func ClearCache() {
 	runtimeOnce = sync.Once{}
 	providerOnce = sync.Once{}
 	agentOnce = sync.Once{}
+	harnessOnce = sync.Once{}
 }
 
 var runtimeOnce sync.Once

useragent/user_agent.go

@@ -16,6 +16,7 @@ const (
 	CicdKey    = "cicd"
 	AuthKey    = "auth"
 	AgentKey   = "agent"
+	HarnessKey = "harness"
 )
 
 // WithProduct sets the product name and product version globally.