all: replace toolsrv.Runner interface with *toolsrv.Conn

The agent always talks to a *Conn (never a *Server directly).
Replace the Runner interface with the concrete type throughout:

- Runtime.ToolServer is now *toolsrv.Conn
- BuildRuntime takes *toolsrv.Conn
- session.Config, SessionInfra, InfraConfig use *toolsrv.Conn
- All inline type assertions in agent.go deleted — methods called
  directly on *Conn (SetEnv, SetCWD, Close, Detach, ListDetachedRaw,
  SignalDetached, GetDetachedOutput, DismissDetached, SetAllowTools,
  SetOnToolsChanged, Ping, ToolRegistryRevision)
- Added Conn.ToolRegistryRevision() that returns 0 (remote connections
  don't support revision tracking; use push-based OnToolsChanged instead)
- Deleted the Runner interface and its test
- Renamed LoadToolOnRunner → LoadToolOnConn

agent/agent.go

@@ -28,7 +28,7 @@ type Agent struct {
 	systemPrompt   string   // system prompt for /agent reloads
 	envBlock       string   // environment block for /agent reloads
 	promptEnvExtra []string // PRIME_* vars for prompt resolution
-	newToolServer  func() toolsrv.Runner
+	newToolServer  func() *toolsrv.Conn
 	newBackend     func(string) (backend.Backend, error)
 	currentAction  atomic.Pointer[actionHandle]
 	warnedContext  bool
@@ -239,7 +239,7 @@ func (ag *Agent) SetOutput(h EventHandler) {
 
 // SetToolServer updates the tool server connection and factory.
 // Used when resuming a paused session that was restored without infra.
-func (ag *Agent) SetToolServer(newToolServer func() toolsrv.Runner, conn toolsrv.Runner) {
+func (ag *Agent) SetToolServer(newToolServer func() *toolsrv.Conn, conn *toolsrv.Conn) {
 	ag.newToolServer = newToolServer
 	if ag.runtime != nil {
 		ag.runtime.ToolServer = conn
@@ -316,16 +316,12 @@ func (ag *Agent) SetSessionEnv(sessionID string) {
 	if ag.runtime.ToolServer == nil {
 		return
 	}
-	if srv := ag.runtime.ToolServer; srv != nil {
+	ag.runtime.ToolServer.SetEnv("OLLIE_SESSION_ID", sessionID)
-		if es, ok := srv.(interface{ SetEnv(string, string) }); ok {
-			es.SetEnv("OLLIE_SESSION_ID", sessionID)
 	if ag.id != "" {
-				es.SetEnv("OLLIE_UNAME", ag.id)
+		ag.runtime.ToolServer.SetEnv("OLLIE_UNAME", ag.id)
 	}
 	if u := os.Getenv("USER"); u != "" {
-				es.SetEnv("USER", u)
+		ag.runtime.ToolServer.SetEnv("USER", u)
-			}
-		}
 	}
 }
 
@@ -334,11 +330,7 @@ func (ag *Agent) SetEnv(key, value string) {
 	if ag.runtime.ToolServer == nil {
 		return
 	}
-	if srv := ag.runtime.ToolServer; srv != nil {
+	ag.runtime.ToolServer.SetEnv(key, value)
-		if es, ok := srv.(interface{ SetEnv(string, string) }); ok {
-			es.SetEnv(key, value)
-		}
-	}
 }
 
 // Close releases agent resources (dispatcher, execute server).
@@ -346,11 +338,7 @@ func (ag *Agent) Close() {
 	if ag.runtime.ToolServer == nil {
 		return
 	}
-	if srv := ag.runtime.ToolServer; srv != nil {
+	ag.runtime.ToolServer.Close()
-		if c, ok := srv.(interface{ Close() }); ok {
-			c.Close()
-		}
-	}
 }
 
 // SetCWD updates the agent's working directory, preamble references, and dispatcher.
@@ -363,11 +351,7 @@ func (ag *Agent) SetCWD(dir string) {
 		ag.runtime.Preamble = strings.ReplaceAll(ag.runtime.Preamble, oldCwd, dir)
 	}
 	if ag.runtime.ToolServer != nil {
-		if srv := ag.runtime.ToolServer; srv != nil {
+		ag.runtime.ToolServer.SetCWD(dir)
-			if ws, ok := srv.(interface{ SetCWD(string) }); ok {
-				ws.SetCWD(dir)
-			}
-		}
 	}
 	ag.notifyChange()
 }
@@ -466,27 +450,18 @@ func (ag *Agent) wireToolsChanged() {
 	if ag.runtime == nil || ag.runtime.ToolServer == nil {
 		return
 	}
-	type hasHook interface {
+	ag.runtime.ToolServer.SetOnToolsChanged(ag.refreshToolListing)
-		SetOnToolsChanged(func(string))
-	}
-	if srv, ok := ag.runtime.ToolServer.(hasHook); ok {
-		srv.SetOnToolsChanged(ag.refreshToolListing)
-	}
 }
 
 // toolsNeedRefresh reports whether the tool registry has changed since the
 // last time Tools was populated. If the tool server doesn't support revision
-// tracking (e.g. remote Conn), this always returns true (safe fallback).
+// tracking (e.g. remote Conn returns 0), this always returns true (safe fallback).
 func (ag *Agent) toolsNeedRefresh() bool {
-	type revisionProvider interface {
+	if ag.runtime.ToolServer == nil {
-		ToolRegistryRevision() uint64
+		return true
 	}
-	srv, ok := ag.runtime.ToolServer.(revisionProvider)
+	rev := ag.runtime.ToolServer.ToolRegistryRevision()
-	if !ok {
+	if rev == 0 || rev != ag.runtime.toolRegistryRevision {
-		return true // no revision support — always refetch
-	}
-	rev := srv.ToolRegistryRevision()
-	if rev != ag.runtime.toolRegistryRevision {
 		ag.runtime.toolRegistryRevision = rev
 		return true
 	}
@@ -577,7 +552,7 @@ func (ag *Agent) ListModels() []string {
 
 // ToolServer returns the tool execution server, or nil if unavailable.
 // Exported for use by the 9P filesystem layer to sync tool registries.
-func (ag *Agent) ToolServer() toolsrv.Runner {
+func (ag *Agent) ToolServer() *toolsrv.Conn {
 	return ag.runtime.ToolServer
 }
 
@@ -600,13 +575,11 @@ func (ag *Agent) BroadcastChange() {
 
 // Detach detaches the current running process to background.
 func (ag *Agent) Detach() bool {
-	if srv := ag.runtime.ToolServer; srv != nil {
+	if ag.runtime.ToolServer == nil {
-		if d, ok := srv.(interface{ Detach() bool }); ok {
-			return d.Detach()
-		}
-	}
 		return false
 	}
+	return ag.runtime.ToolServer.Detach()
+}
 
 // DetachedInfo describes a detached process.
 type DetachedInfo struct {
@@ -619,16 +592,10 @@ type DetachedInfo struct {
 
 // ListDetached returns info about all detached processes.
 func (ag *Agent) ListDetached() []DetachedInfo {
-	srv := ag.runtime.ToolServer
+	if ag.runtime.ToolServer == nil {
-	if srv == nil {
 		return nil
 	}
-	type listDetacher interface{ ListDetachedRaw() []any }
+	raw := ag.runtime.ToolServer.ListDetachedRaw()
-	ld, ok := srv.(listDetacher)
-	if !ok {
-		return nil
-	}
-	raw := ld.ListDetachedRaw()
 	out := make([]DetachedInfo, 0, len(raw))
 	for _, r := range raw {
 		if m, ok := r.(map[string]any); ok {
@@ -656,35 +623,24 @@ func (ag *Agent) ListDetached() []DetachedInfo {
 
 // SignalDetached sends a signal to a detached process.
 func (ag *Agent) SignalDetached(pid int, signal int) error {
-	if srv := ag.runtime.ToolServer; srv != nil {
+	if ag.runtime.ToolServer == nil {
-		type signaler interface {
-			SignalDetached(int, syscall.Signal) error
-		}
-		if sg, ok := srv.(signaler); ok {
-			return sg.SignalDetached(pid, syscall.Signal(signal))
-		}
-	}
 		return fmt.Errorf("no execute server available")
 	}
+	return ag.runtime.ToolServer.SignalDetached(pid, syscall.Signal(signal))
+}
 
 // GetDetachedOutput reads output from a detached process.
 func (ag *Agent) GetDetachedOutput(pid int) (string, error) {
-	if srv := ag.runtime.ToolServer; srv != nil {
+	if ag.runtime.ToolServer == nil {
-		type outputGetter interface{ GetDetachedOutput(int) (string, error) }
-		if og, ok := srv.(outputGetter); ok {
-			return og.GetDetachedOutput(pid)
-		}
-	}
 		return "", fmt.Errorf("no execute server available")
 	}
+	return ag.runtime.ToolServer.GetDetachedOutput(pid)
+}
 
 // DismissDetached removes a finished detached process.
 func (ag *Agent) DismissDetached(pid int) bool {
-	if srv := ag.runtime.ToolServer; srv != nil {
+	if ag.runtime.ToolServer == nil {
-		type dismisser interface{ DismissDetached(int) bool }
-		if d, ok := srv.(dismisser); ok {
-			return d.DismissDetached(pid)
-		}
-	}
 		return false
 	}
+	return ag.runtime.ToolServer.DismissDetached(pid)
+}

agent/build_runtime.go

@@ -18,7 +18,7 @@ import (
 // env provides additional environment variables injected into prompt resolution
 // subprocesses (e.g. OLLIE_SESSION_ID=xxx).
 // The caller is responsible for registering all servers on d before calling this.
-func BuildRuntime(cfg *AgentConfig, srv toolsrv.Runner, cwd string, env []string, systemPrompt, envBlock string) *Runtime {
+func BuildRuntime(cfg *AgentConfig, srv *toolsrv.Conn, cwd string, env []string, systemPrompt, envBlock string) *Runtime {
 	var messages []string
 
 	var allToolInfos []toolsrv.ToolInfo
@@ -45,10 +45,8 @@ func BuildRuntime(cfg *AgentConfig, srv toolsrv.Runner, cwd string, env []string
 		}
 		genParams = cfg.GenParams()
 		maxSteps = cfg.MaxSteps
-		if len(cfg.AllowTools) > 0 {
+		if len(cfg.AllowTools) > 0 && srv != nil {
-			if rs, ok := srv.(interface{ SetAllowTools([]string) }); ok {
+			srv.SetAllowTools(cfg.AllowTools)
-				rs.SetAllowTools(cfg.AllowTools)
-			}
 		}
 	}
 

agent/new.go

@@ -20,7 +20,7 @@ type AgentCfg struct {
 	SystemPrompt   string
 	EnvBlock       string
 	PromptEnvExtra []string
-	NewToolServer  func() toolsrv.Runner
+	NewToolServer  func() *toolsrv.Conn
 	NewBackend     func(string) (backend.Backend, error)
 	Output         EventHandler
 	Log            *olog.Logger

agent/runtime.go

@@ -11,7 +11,7 @@ import (
 // agents replaces it atomically.
 type Runtime struct {
 	Backend    backend.Backend
-	ToolServer toolsrv.Runner // the execute server (tool runtime, env, cwd)
+	ToolServer *toolsrv.Conn // the tool server connection (tool runtime, env, cwd)
 	Preamble   string         // compiled system prompt
 	Tools      []backend.Tool
 	ToolMeta   map[string]toolsrv.ToolInfo // keyed by tool name — source of truth for all per-tool metadata

fs/session_node.go

@@ -65,7 +65,7 @@ func (s *SessionNode) Ctx() context.Context {
 	return s.Core.Ctx()
 }
 
-func (s *SessionNode) ToolsConn() toolsrv.Runner {
+func (s *SessionNode) ToolsConn() *toolsrv.Conn {
 	return s.Core.ToolsConn()
 }
 

session/persist.go

@@ -277,8 +277,8 @@ func restoreMultiAgentSession(ps *PersistedSession) (*RestoredSession, error) {
 		env := []string{"OLLIE_SESSION_ID=" + ps.ID, "OLLIE_UNAME=" + pa.ID}
 		env = append(env, promptEnv...)
 
-		var toolsConn toolsrv.Runner
+		var toolsConn *toolsrv.Conn
-		var newToolServer func() toolsrv.Runner
+		var newToolServer func() *toolsrv.Conn
 		if infra != nil {
 			toolsConn = infra.ToolsConn
 			newToolServer = infra.NewToolServer

session/session.go

@@ -31,7 +31,7 @@ type Config struct {
 	CWD            string
 	History        *agent.History
 	Runtime        *agent.Runtime
-	NewToolServer  func() toolsrv.Runner
+	NewToolServer  func() *toolsrv.Conn
 	NewBackend     func(string) (backend.Backend, error)
 	Log            *olog.Logger
 	MaxSteps       int
@@ -72,7 +72,7 @@ type Session struct {
 	// Tool server lifecycle
 	proc      *toolsrv.Process       // toolsrv subprocess
 	keeper    *toolsrv.ProcessKeeper // resilient process manager
-	toolsConn toolsrv.Runner         // multiplexed RPC connection
+	toolsConn *toolsrv.Conn // multiplexed RPC connection
 	paused    bool                   // true when paused
 
 	// Tool restrictions
@@ -426,14 +426,14 @@ func (s *Session) SetKeeper(keeper *toolsrv.ProcessKeeper) {
 }
 
 // ToolsConn returns the tool server connection.
-func (s *Session) ToolsConn() toolsrv.Runner {
+func (s *Session) ToolsConn() *toolsrv.Conn {
 	s.mu.RLock()
 	defer s.mu.RUnlock()
 	return s.toolsConn
 }
 
 // SetToolsConn sets the tool server connection.
-func (s *Session) SetToolsConn(conn toolsrv.Runner) {
+func (s *Session) SetToolsConn(conn *toolsrv.Conn) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 	s.toolsConn = conn
@@ -463,10 +463,7 @@ func (s *Session) IsConnected() bool {
 	if paused || conn == nil {
 		return false
 	}
-	if pinger, ok := conn.(interface{ Ping() error }); ok {
+	return conn.Ping() == nil
-		return pinger.Ping() == nil
-	}
-	return true
 }
 
 // Pause stops the tool server to save resources.
@@ -490,9 +487,7 @@ func (s *Session) Pause() error {
 	}
 	// Close any existing connection.
 	if s.toolsConn != nil {
-		if c, ok := s.toolsConn.(interface{ Close() }); ok {
+		s.toolsConn.Close()
-			c.Close()
-		}
 		s.toolsConn = nil
 	}
 	s.paused = true
@@ -591,24 +586,24 @@ func (s *Session) LoadTool(name string, ag *agent.Agent) error {
 	if blocked {
 		return fmt.Errorf("tool %q is disallowed for this session", name)
 	}
-	var runner toolsrv.Runner
+	var conn *toolsrv.Conn
 	if s.toolsConn != nil {
-		runner = s.toolsConn
+		conn = s.toolsConn
 	} else if ag != nil {
-		runner = ag.ToolServer()
+		conn = ag.ToolServer()
 	}
-	return LoadToolOnRunner(runner, name)
+	return LoadToolOnConn(conn, name)
 }
 
-// LoadToolOnRunner loads a tool on the given runner.
+// LoadToolOnConn loads a tool on the given connection.
-func LoadToolOnRunner(runner toolsrv.Runner, name string) error {
+func LoadToolOnConn(conn *toolsrv.Conn, name string) error {
-	if runner == nil {
+	if conn == nil {
 		return nil
 	}
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 	args, _ := json.Marshal(map[string]string{"name": name})
-	if _, err := runner.CallTool(ctx, "tool_load", json.RawMessage(args)); err != nil {
+	if _, err := conn.CallTool(ctx, "tool_load", json.RawMessage(args)); err != nil {
 		return fmt.Errorf("remote load: %w", err)
 	}
 	return nil

session/setup.go

@@ -15,8 +15,8 @@ import (
 type SessionInfra struct {
 	Proc          *toolsrv.Process
 	Keeper        *toolsrv.ProcessKeeper
-	ToolsConn     toolsrv.Runner
+	ToolsConn     *toolsrv.Conn
-	NewToolServer func() toolsrv.Runner
+	NewToolServer func() *toolsrv.Conn
 	PromptEnv     []string
 }
 
@@ -36,7 +36,7 @@ type ToolServerConfig struct {
 type InfraConfig struct {
 	Proc      *toolsrv.Process
 	Keeper    *toolsrv.ProcessKeeper
-	ToolsConn toolsrv.Runner
+	ToolsConn *toolsrv.Conn
 }
 
 // SetupToolServer spawns the tool server process and creates the infrastructure.
@@ -47,9 +47,9 @@ func SetupToolServer(cfg ToolServerConfig) (*SessionInfra, error) {
 	// Reuse existing infrastructure if provided.
 	if cfg.ReuseFrom != nil {
 		r := cfg.ReuseFrom
-		var newToolServer func() toolsrv.Runner
+		var newToolServer func() *toolsrv.Conn
 		if r.Keeper != nil {
-			newToolServer = func() toolsrv.Runner {
+			newToolServer = func() *toolsrv.Conn {
 				conn, err := r.Keeper.Dial()
 				if err != nil {
 					return nil
@@ -57,13 +57,13 @@ func SetupToolServer(cfg ToolServerConfig) (*SessionInfra, error) {
 				return conn
 			}
 		} else {
-			newToolServer = func() toolsrv.Runner {
+			newToolServer = func() *toolsrv.Conn {
 				return r.ToolsConn
 			}
 		}
-		// Update CWD if the connection supports it.
+		// Update CWD on the reused connection.
-		if cwc, ok := r.ToolsConn.(interface{ SetCWD(string) }); ok {
+		if r.ToolsConn != nil {
-			cwc.SetCWD(cfg.CWD)
+			r.ToolsConn.SetCWD(cfg.CWD)
 		}
 		return &SessionInfra{
 			Proc:          r.Proc,
@@ -75,7 +75,7 @@ func SetupToolServer(cfg ToolServerConfig) (*SessionInfra, error) {
 	}
 	var proc *toolsrv.Process
 	var keeper *toolsrv.ProcessKeeper
-	var newToolServer func() toolsrv.Runner
+	var newToolServer func() *toolsrv.Conn
 	var promptEnv []string
 	var err error
 
@@ -93,7 +93,7 @@ func SetupToolServer(cfg ToolServerConfig) (*SessionInfra, error) {
 				CWD:       cfg.CWD,
 			})
 		})
-		newToolServer = func() toolsrv.Runner {
+		newToolServer = func() *toolsrv.Conn {
 			conn, err := keeper.Dial()
 			if err != nil {
 				return nil
@@ -117,7 +117,7 @@ func SetupToolServer(cfg ToolServerConfig) (*SessionInfra, error) {
 		keeper = toolsrv.NewProcessKeeper(cfg.Ctx, proc, func(ctx context.Context) (*toolsrv.Process, error) {
 			return toolsrv.Spawn(ctx, cfg.CWD, dialOpts...)
 		})
-		newToolServer = func() toolsrv.Runner {
+		newToolServer = func() *toolsrv.Conn {
 			conn, err := keeper.Dial()
 			if err != nil {
 				return nil
@@ -178,24 +178,22 @@ func BuildPromptLayers(cfg *agent.AgentConfig, cwd, sessID, uname string, prompt
 // LoadAutoLoadTools loads all tools from the agent config's autoLoad list.
 // It first sends the session ID and uname to the tool server so that
 // ollie-remote can attach its tool registry before processing tool_load RPCs.
-func LoadAutoLoadTools(cfg *agent.AgentConfig, runner toolsrv.Runner, sessID, uname string, logError func(string, ...any)) {
+func LoadAutoLoadTools(cfg *agent.AgentConfig, conn *toolsrv.Conn, sessID, uname string, logError func(string, ...any)) {
-	if cfg == nil || runner == nil {
+	if cfg == nil || conn == nil {
 		return
 	}
 
 	// Send session ID to the tool server first — ollie-remote uses this
 	// to attach its tool registry via the OnEnvSet callback.
-	if es, ok := runner.(interface{ SetEnv(string, string) }); ok {
 	if sessID != "" {
-			es.SetEnv("OLLIE_SESSION_ID", sessID)
+		conn.SetEnv("OLLIE_SESSION_ID", sessID)
 	}
 	if uname != "" {
-			es.SetEnv("OLLIE_UNAME", uname)
+		conn.SetEnv("OLLIE_UNAME", uname)
-		}
 	}
 
 	for _, tl := range cfg.AutoLoad {
-		if err := LoadToolOnRunner(runner, tl); err != nil {
+		if err := LoadToolOnConn(conn, tl); err != nil {
 			if logError != nil {
 				logError("autoLoad tool %q: %v", tl, err)
 			}

toolsrv/conn.go

@@ -103,6 +103,10 @@ func (c *Conn) SetOnToolsChanged(fn func(string)) {
 	c.pendingMu.Unlock()
 }
 
+// ToolRegistryRevision returns 0 for remote connections (revision tracking
+// is not supported over RPC; use SetOnToolsChanged for push-based refresh).
+func (c *Conn) ToolRegistryRevision() uint64 { return 0 }
+
 func (c *Conn) Detach() bool {
 	resp, err := c.call("detach", nil)
 	if err != nil {

toolsrv/tools.go

@@ -3,7 +3,6 @@
 package toolsrv
 
 import (
-	"context"
 	"encoding/json"
 )
 
@@ -29,10 +28,3 @@ type ToolInfo struct {
 	// the soft step-budget guardrail.
 	ResetsCounter bool
 }
-
-// Runner is the minimal interface satisfied by any tool server (local or remote).
-// Consumers that need polymorphism over Server and RemoteServer use this.
-type Runner interface {
-	ListTools() ([]ToolInfo, error)
-	CallTool(ctx context.Context, tool string, args json.RawMessage) (json.RawMessage, error)
-}

toolsrv/tools_test.go

@@ -1,53 +0,0 @@
-package toolsrv_test
-
-import (
-	"context"
-	"encoding/json"
-	"testing"
-
-	"ollie/toolsrv"
-)
-
-// stubRunner is a minimal Runner used to verify the contract.
-type stubRunner struct {
-	name  string
-	tools []toolsrv.ToolInfo
-}
-
-func (s *stubRunner) ListTools() ([]toolsrv.ToolInfo, error) { return s.tools, nil }
-func (s *stubRunner) CallTool(_ context.Context, tool string, _ json.RawMessage) (json.RawMessage, error) {
-	return json.RawMessage(`{"tool":"` + tool + `"}`), nil
-}
-
-func newStub(name string, toolNames ...string) *stubRunner {
-	var ti []toolsrv.ToolInfo
-	for _, n := range toolNames {
-		ti = append(ti, toolsrv.ToolInfo{Name: n, Description: n + " desc"})
-	}
-	return &stubRunner{name: name, tools: ti}
-}
-
-// checkRunnerContract verifies Runner invariants.
-func checkRunnerContract(t *testing.T, r toolsrv.Runner) {
-	t.Helper()
-	tl, err := r.ListTools()
-	if err != nil {
-		t.Fatalf("ListTools: %v", err)
-	}
-	if tl == nil {
-		t.Fatal("ListTools returned nil")
-	}
-	for _, ti := range tl {
-		res, err := r.CallTool(context.Background(), ti.Name, json.RawMessage(`{}`))
-		if err != nil {
-			t.Errorf("CallTool(%q): %v", ti.Name, err)
-		}
-		if len(res) == 0 {
-			t.Errorf("CallTool(%q) returned empty result", ti.Name)
-		}
-	}
-}
-
-func TestStubRunnerContract(t *testing.T) {
-	checkRunnerContract(t, newStub("s", "a", "b"))
-}