feat(backend): add Hermes ACP agent support (#1090)

apps/backend/internal/agent/agents/hermes_acp.go

@@ -0,0 +1,127 @@
+//nolint:dupl // Native-binary ACP agents (Cursor, Kimi, Kiro, Qoder, Trae, Hermes) follow the same minimal scaffold; differences are the binary name and subcommand.
+package agents
+
+import (
+	"context"
+	_ "embed"
+	"time"
+
+	"github.com/kandev/kandev/internal/agent/usage"
+	"github.com/kandev/kandev/pkg/agent"
+)
+
+//go:embed logos/hermes_acp_light.svg
+var hermesACPLogoLight []byte
+
+//go:embed logos/hermes_acp_dark.svg
+var hermesACPLogoDark []byte
+
+const hermesACPBin = "hermes"
+
+var (
+	_ Agent            = (*HermesACP)(nil)
+	_ PassthroughAgent = (*HermesACP)(nil)
+	_ InferenceAgent   = (*HermesACP)(nil)
+)
+
+// HermesACP implements Agent for Nous Research's Hermes CLI using ACP.
+// Not on npm — installation is a multi-step Python/uv flow documented
+// upstream, so InstallScript() points at the docs rather than offering
+// a one-shot install button.
+type HermesACP struct {
+	StandardPassthrough
+}
+
+func NewHermesACP() *HermesACP {
+	return &HermesACP{
+		StandardPassthrough: StandardPassthrough{
+			PermSettings: emptyPermSettings,
+			Cfg: PassthroughConfig{
+				Supported:      true,
+				Label:          "CLI Passthrough",
+				Description:    "Show terminal directly instead of chat interface",
+				PassthroughCmd: NewCommand(hermesACPBin),
+				ModelFlag:      NewParam("--model", "{model}"),
+				IdleTimeout:    3 * time.Second,
+				BufferMaxBytes: DefaultBufferMaxBytes,
+			},
+		},
+	}
+}
+
+func (a *HermesACP) ID() string          { return "hermes-acp" }
+func (a *HermesACP) Name() string        { return "Hermes ACP Agent" }
+func (a *HermesACP) DisplayName() string { return "Hermes" }
+func (a *HermesACP) Description() string {
+	return "Nous Research Hermes self-improving coding agent using the ACP protocol over stdin/stdout."
+}
+func (a *HermesACP) Enabled() bool     { return true }
+func (a *HermesACP) DisplayOrder() int { return 19 }
+
+func (a *HermesACP) Logo(v LogoVariant) []byte {
+	if v == LogoDark {
+		return hermesACPLogoDark
+	}
+	return hermesACPLogoLight
+}
+
+func (a *HermesACP) IsInstalled(ctx context.Context) (*DiscoveryResult, error) {
+	// The `hermes` binary name collides with Meta's Hermes JavaScript engine
+	// (distributed via `hermes-engine` npm; occasionally globally installed in
+	// React Native setups). A bare LookPath would report Available=true for
+	// that stray binary, then `hermes acp` would fail and surface a misleading
+	// auth_required state. Match the Nous Research version banner
+	// ("Hermes Agent v…", emitted by cli.py) so detection is specific.
+	result, err := Detect(ctx, WithCommandOutput(`(?i)hermes\s+agent`, hermesACPBin, "--version"))
+	if err != nil {
+		return result, err
+	}
+	result.SupportsMCP = true
+	result.Capabilities = DiscoveryCapabilities{
+		SupportsSessionResume: true,
+	}
+	return result, nil
+}
+
+func (a *HermesACP) BuildCommand(opts CommandOptions) Command {
+	return Cmd(hermesACPBin, "acp").Build()
+}
+
+func (a *HermesACP) Runtime() *RuntimeConfig {
+	canRecover := true
+	return &RuntimeConfig{
+		Cmd:            Cmd(hermesACPBin, "acp").Build(),
+		WorkingDir:     "{workspace}",
+		Env:            map[string]string{},
+		ResourceLimits: ResourceLimits{MemoryMB: 4096, CPUCores: 2.0, Timeout: time.Hour},
+		Protocol:       agent.ProtocolACP,
+		SessionConfig: SessionConfig{
+			NativeSessionResume: true,
+			CanRecover:          &canRecover,
+			SessionDirTemplate:  "{home}/.hermes",
+		},
+	}
+}
+
+func (a *HermesACP) RemoteAuth() *RemoteAuth { return nil }
+
+func (a *HermesACP) InstallScript() string {
+	// Hermes ships a multi-step Python/uv installer that may need system
+	// packages and a one-time `hermes setup` afterwards — not a clean
+	// one-shot like `npm install -g`. Point users at the upstream docs
+	// instead of pretending the install button can handle it.
+	return "Install Hermes from https://hermes-agent.nousresearch.com/docs/getting-started"
+}
+
+func (a *HermesACP) PermissionSettings() map[string]PermissionSetting {
+	return emptyPermSettings
+}
+
+func (a *HermesACP) InferenceConfig() *InferenceConfig {
+	return &InferenceConfig{
+		Supported: true,
+		Command:   NewCommand(hermesACPBin, "acp"),
+	}
+}
+
+func (a *HermesACP) BillingType() usage.BillingType { return defaultBillingType() }

apps/backend/internal/agent/agents/new_acp_agents_test.go

@@ -122,6 +122,13 @@ grep -qxF 'export PATH="$HOME/.local/bin:$PATH"' "$HOME/.bashrc" 2>/dev/null ||
 		passthroughArgv: []string{"omp"},
 		installViaNpm:   false,
 	}},
+	{func() Agent { return NewHermesACP() }, acpAgentSpec{
+		id: "hermes-acp", displayName: "Hermes", detectBinaries: []string{"hermes"},
+		expectedArgv:    []string{"hermes", "acp"},
+		inferenceArgv:   []string{"hermes", "acp"},
+		passthroughArgv: []string{"hermes"},
+		installViaNpm:   false,
+	}},
 }
 
 func TestNewACPAgents_IDAndDisplay(t *testing.T) {

apps/backend/internal/agent/registry/registry.go

@@ -62,6 +62,7 @@ func (r *Registry) LoadDefaults() {
 		agents.NewQoderACP(),
 		agents.NewTraeACP(),
 		agents.NewOmpACP(),
+		agents.NewHermesACP(),
 		agents.NewMockAgent(),
 	}
 

apps/backend/internal/agentctl/server/utility/acp_executor.go

@@ -477,6 +477,7 @@ func derefString(p *string) string {
 var allowedProbeCommands = map[string]string{
 	"auggie":        "auggie",
 	"cursor-agent":  "cursor-agent",
+	"hermes":        "hermes",
 	"kimi":          "kimi",
 	"kiro-cli-chat": "kiro-cli-chat",
 	"mock-agent":    "mock-agent",