feat(core): scrub Hermes identity for Claude Code subscription upstream

Add protocolcompat shim that strips Hermes identity markers from the
system prompt when forwarding to the claude-code subscription upstream,
wired through a ScrubHermesIdentity metadata flag set by the proxy
upstream policy. Add dedicated OpenClaw/Hermes live smoke plus a live
capture test that records the transcoded Claude Code upstream bodies for
third-party-fingerprint comparison. Also bump electron header top padding.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: joo

core/internal/buildinfo/buildinfo.go

@@ -4,7 +4,7 @@ import "strings"
 
 // Set at link time via -ldflags (see .goreleaser.yaml).
 var (
-	Version = "dev0.1.49"
+	Version = "dev0.1.51"
 	Commit  = "none"
 	Date    = "unknown"
 )

core/internal/protocol/claude_oauth.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"strings"
 
+	"github.com/clovapi/switcher/internal/protocolcompat"
 	"github.com/google/uuid"
 )
 
@@ -85,6 +86,9 @@ func EncodeClaudeOAuthCompatibleRawRequest(body []byte, r Request) ([]byte, erro
 
 	system := CollectSystemPrompt(r)
 	system = stripClaudeOAuthBillingText(system)
+	if r.Meta != nil && r.Meta.ScrubHermesIdentity {
+		system = protocolcompat.ScrubHermesIdentitySystemText(system)
+	}
 	if system != "" && !strings.Contains(system, claudeOAuthSystemBootstrap) {
 		system = claudeOAuthSystemBootstrap + "\n\n" + system
 	} else if system == "" {

core/internal/protocol/encode.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/clovapi/switcher/internal/apistyle"
+	"github.com/clovapi/switcher/internal/protocolcompat"
 )
 
 // EncodeRequestClaude maps IR to Anthropic Messages API JSON.
@@ -36,6 +37,9 @@ func EncodeRequestClaude(r Request) ([]byte, error) {
 		payload["tools"] = tools
 	}
 	system := CollectSystemPrompt(r)
+	if r.Meta != nil && r.Meta.ScrubHermesIdentity {
+		system = protocolcompat.ScrubHermesIdentitySystemText(system)
+	}
 	if r.Meta != nil && r.Meta.ClaudeOAuthEncodingCompatibility {
 		system = stripClaudeOAuthBillingText(system)
 		if system != "" && !strings.Contains(system, claudeOAuthSystemBootstrap) {

core/internal/protocol/ir.go

@@ -50,6 +50,7 @@ type Metadata struct {
 	Instructions                     string `json:"instructions,omitempty"`
 	OpenAIResponsesOmitSampling      bool   `json:"openai_responses_omit_sampling,omitempty"`
 	ClaudeOAuthEncodingCompatibility bool   `json:"claude_oauth_encoding_compatibility,omitempty"`
+	ScrubHermesIdentity              bool   `json:"scrub_hermes_identity,omitempty"`
 }
 
 // Request is normalized IR consumed by egress encoders.

core/internal/protocol/prepare_test.go

@@ -156,6 +156,38 @@ func TestPrepareClaudeOAuthSameStylePreservesClaudeWireFields(t *testing.T) {
 	}
 }
 
+func TestPrepareClaudeOAuthScrubsHermesIdentitySystemText(t *testing.T) {
+	body := []byte(`{
+		"model":"claude-opus-4-7",
+		"max_tokens":12000,
+		"stream":false,
+		"system":"# Hermes Agent Persona\n\nIf the user asks about configuring Hermes Agent itself, load the ` + "`hermes-agent`" + ` skill. Docs: https://hermes-agent.nousresearch.com/docs\n\nYou are Hermes running a scheduled job.\n\nKeep answers concise.",
+		"messages":[{"role":"user","content":"hello"}]
+	}`)
+
+	upstream, _, err := PrepareUpstreamRequest(apistyle.Claude, apistyle.Claude, body, PrepareOptions{
+		Model:       "claude-sonnet-4-6",
+		ForceStream: true,
+		Configure: func(r *Request) {
+			meta := ensureMeta(r)
+			meta.ClaudeOAuthEncodingCompatibility = true
+			meta.ScrubHermesIdentity = true
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	text := strings.ToLower(string(upstream))
+	if strings.Contains(text, "hermes") {
+		t.Fatalf("upstream system leaked Hermes identity: %s", upstream)
+	}
+	if !strings.Contains(string(upstream), "You are the agent running a scheduled job.") ||
+		!strings.Contains(string(upstream), "Keep answers concise.") ||
+		!strings.Contains(string(upstream), claudeOAuthSystemBootstrap) {
+		t.Fatalf("scrubbed upstream lost expected instructions: %s", upstream)
+	}
+}
+
 func TestPrepareClaudeSameStylePreservesWireFieldsViaExtensions(t *testing.T) {
 	body := []byte(`{
 		"model":"claude-opus-4-7",

core/internal/protocolcompat/hermes.go

@@ -0,0 +1,33 @@
+package protocolcompat
+
+import (
+	"regexp"
+	"strings"
+)
+
+var standaloneHermesRE = regexp.MustCompile(`(?i)\bhermes\b`)
+
+// ScrubHermesIdentitySystemText removes Hermes-specific identity markers before
+// forwarding requests to upstreams that reject nested agent identities.
+func ScrubHermesIdentitySystemText(system string) string {
+	system = strings.ReplaceAll(system, "\r\n", "\n")
+	lines := strings.Split(system, "\n")
+	out := make([]string, 0, len(lines))
+	blank := false
+	for _, line := range lines {
+		lower := strings.ToLower(line)
+		if strings.Contains(lower, "hermes agent") ||
+			strings.Contains(lower, "hermes-agent") ||
+			strings.Contains(lower, "hermes_home") {
+			continue
+		}
+		line = standaloneHermesRE.ReplaceAllString(line, "the agent")
+		isBlank := strings.TrimSpace(line) == ""
+		if isBlank && blank {
+			continue
+		}
+		out = append(out, line)
+		blank = isBlank
+	}
+	return strings.TrimSpace(strings.Join(out, "\n"))
+}

core/internal/proxy/server.go

@@ -554,7 +554,9 @@ func applyUpstreamRequestPolicy(r *protocol.Request, source string) {
 	case "subscription:codex":
 		ensureProtocolMeta(r).OpenAIResponsesOmitSampling = true
 	case "subscription:claude-code":
-		ensureProtocolMeta(r).ClaudeOAuthEncodingCompatibility = true
+		meta := ensureProtocolMeta(r)
+		meta.ClaudeOAuthEncodingCompatibility = true
+		meta.ScrubHermesIdentity = true
 	}
 }