Send agent enum for agent-shim telemetry events (#7019)

## Changes

Replace `agent_name` with `agent` and make the values match JSON->proto
deserialization for enums (e.g. "CLAUDE_CODE" instead of "claude")

## Why

The original PR to add this event didn't follow telemetry best
practices, this PR fixes that

## Tests
automated tests pass

Author: rclarey

experimental/ssh/internal/client/agentshim.go

@@ -85,7 +85,8 @@ const (
 )
 
 type agentSpec struct {
-	name string
+	name          string
+	telemetryName protos.SshAgentShimAgent
 	// contextFlag passes the context file via this CLI flag (Claude's --append-system-prompt-file).
 	contextFlag string
 	// contextHomeFile writes the context to this $HOME instructions file (codex's AGENTS.md).
@@ -94,8 +95,8 @@ type agentSpec struct {
 
 // Currently limited to the agents whose Unity Gateway CLI command supports --workspace
 var supportedAgents = []agentSpec{
-	{name: "claude", contextFlag: "--append-system-prompt-file"},
-	{name: "codex", contextHomeFile: ".codex/AGENTS.md"},
+	{name: "claude", telemetryName: protos.SshAgentShimAgentClaudeCode, contextFlag: "--append-system-prompt-file"},
+	{name: "codex", telemetryName: protos.SshAgentShimAgentCodex, contextHomeFile: ".codex/AGENTS.md"},
 }
 
 // SupportedAgentNames lists the agents the ssh command registers a subcommand for.
@@ -237,8 +238,15 @@ func logAgentShimEvent(ctx context.Context, agentName string, outcome agentShimO
 // buildAgentShimEvent maps the agent name and outcome onto the telemetry event. It is
 // separated from logAgentShimEvent so the field mapping can be unit tested.
 func buildAgentShimEvent(agentName string, outcome agentShimOutcome, setupDuration time.Duration) *protos.SshAgentShimEvent {
+	// lookup agent by name so this function is the single decision point for
+	// telemetry and is easily testable
+	telemetryName := protos.SshAgentShimAgentUnspecified
+	agent, ok := agentByName(agentName)
+	if ok {
+		telemetryName = agent.telemetryName
+	}
 	return &protos.SshAgentShimEvent{
-		AgentName:       agentName,
+		Agent:           telemetryName,
 		IsSuccess:       outcome.err == nil,
 		ErrorCategory:   outcome.category(),
 		SetupDurationMs: setupDuration.Milliseconds(),

experimental/ssh/internal/client/agentshim_test.go

@@ -565,10 +565,22 @@ func TestProbeModelServicesPageError(t *testing.T) {
 }
 
 func TestBuildAgentShimEvent(t *testing.T) {
+	for _, agent := range supportedAgents {
+		t.Run(agent.name+" has an appropriate enum for telemetry", func(t *testing.T) {
+			got := buildAgentShimEvent(agent.name, agentShimOutcome{}, 0)
+			assert.NotEqual(t, protos.SshAgentShimAgentUnspecified, got.Agent)
+		})
+	}
+
+	t.Run("maps an unknown agent to unspecified", func(t *testing.T) {
+		got := buildAgentShimEvent("wibble", agentShimOutcome{}, 0)
+		assert.Equal(t, protos.SshAgentShimAgentUnspecified, got.Agent)
+	})
+
 	t.Run("successful launch reports success and no category", func(t *testing.T) {
 		got := buildAgentShimEvent("claude", agentShimOutcome{}, 1500*time.Millisecond)
 		assert.Equal(t, &protos.SshAgentShimEvent{
-			AgentName:       "claude",
+			Agent:           protos.SshAgentShimAgentClaudeCode,
 			IsSuccess:       true,
 			ErrorCategory:   protos.SshAgentShimErrorCategoryUnspecified,
 			SetupDurationMs: 1500,
@@ -580,7 +592,7 @@ func TestBuildAgentShimEvent(t *testing.T) {
 			err: categorize(protos.SshAgentShimErrorCategoryGatewayAuthFailed, errors.New("boom")),
 		}, 200*time.Millisecond)
 		assert.Equal(t, &protos.SshAgentShimEvent{
-			AgentName:       "codex",
+			Agent:           protos.SshAgentShimAgentCodex,
 			IsSuccess:       false,
 			ErrorCategory:   protos.SshAgentShimErrorCategoryGatewayAuthFailed,
 			SetupDurationMs: 200,

libs/telemetry/protos/ssh_agent_shim.go

@@ -81,6 +81,21 @@ const (
 	SshAgentShimErrorCategoryUnknown SshAgentShimErrorCategory = "UNKNOWN"
 )
 
+// The agent for an `ssh agent-shim <agent>` command invocation. Values are in
+// screaming snake case to match what JSON->proto deserialization expects.
+type SshAgentShimAgent string
+
+const (
+	// Unknown agent was specified.
+	SshAgentShimAgentUnspecified SshAgentShimAgent = "TYPE_UNSPECIFIED"
+
+	// Claude Code CLI.
+	SshAgentShimAgentClaudeCode SshAgentShimAgent = "CLAUDE_CODE"
+
+	// Codex CLI.
+	SshAgentShimAgentCodex SshAgentShimAgent = "CODEX"
+)
+
 // SshAgentShimEvent is emitted when a user runs `ssh agent-shim <agent>` on the remote
 // driver to launch a coding agent against the Unity AI Gateway.
 //
@@ -89,9 +104,9 @@ const (
 // uploaded from the shim just before the exec. A failed launch returns normally and is
 // uploaded by cmd/root as usual.
 type SshAgentShimEvent struct {
-	// Name of the agent the user asked to launch (e.g. "claude", "codex"). Drawn from a
-	// fixed set of CLI-defined identifiers, never user-authored text.
-	AgentName string `json:"agent_name"`
+	//  The agent the user asked to launch, mapped to a string matching the proto enum
+	// (e.g. "CLAUDE_CODE", "CODEX", etc).
+	Agent SshAgentShimAgent `json:"agent"`
 
 	// Whether the agent was launched. False means setup failed before the agent ran.
 	// Populated on every event, so no omitempty: a genuine false must stay distinguishable

libs/telemetry/protos/ssh_agent_shim_test.go

@@ -21,7 +21,7 @@ func TestSshAgentShimEventEncodesFailureExplicitly(t *testing.T) {
 	assert.Equal(t, false, got["is_success"], "is_success must be sent as false, not omitted")
 	// The remaining fields must appear in the payload at all: omitempty would drop the
 	// zero value and make a failure indistinguishable from an unreported one.
-	for _, field := range []string{"agent_name", "error_category", "setup_duration_ms"} {
+	for _, field := range []string{"agent", "error_category", "setup_duration_ms"} {
 		assert.Contains(t, got, field, "%s must be sent, not omitted", field)
 	}
 }