fb35dff fix: run MCP servers from project directory · zut

M examples/extensions/mcp-bridge/bridge.go +4 -2


@@ -33,6 +33,7 @@ type toolMapping struct {
33	33		// bridge connects MCP servers to zot's extension protocol.
34	34		type bridge struct {
35	35		e *ext.Extension
	36	+	cwd string
36	37		// servers is written once in loadServers before any goroutine
37	38		// starts, and read-only afterwards — that invariant is what makes
38	39		// the lock-free reads in handleToolCall and the idle reaper safe.

@@ -45,9 +46,10 @@ type bridge struct {
45	46		}
46	47
47	48		// newBridge creates a new MCP→zot bridge.
48		-	func newBridge(e ext.Extension, logger log.Logger) *bridge {
	49	+	func newBridge(e ext.Extension, cwd string, logger log.Logger) *bridge {
49	50		return &bridge{
50	51		e: e,
	52	+	cwd: cwd,
51	53		servers: make(map[string]*managedServer),
52	54		mapping: make(map[string]toolMapping),
53	55		logger: logger,

@@ -78,7 +80,7 @@ func toolName(serverName, mcpToolName string) string {
78	80		// loadServers reads the config and creates managed servers.
79	81		func (b *bridge) loadServers(cfg Config) {
80	82		for name, srvCfg := range cfg.MCPServers {
81		-	srv := newManagedServer(name, srvCfg, b.logger)
	83	+	srv := newManagedServer(name, srvCfg, b.cwd, b.logger)
82	84		b.servers[name] = srv
83	85		}
84	86		}

 // bridge connects MCP servers to zot's extension protocol.
 type bridge struct {
 	e *ext.Extension
+	cwd string
 	// servers is written once in loadServers before any goroutine
 	// starts, and read-only afterwards — that invariant is what makes
 	// the lock-free reads in handleToolCall and the idle reaper safe.
 }
 // newBridge creates a new MCP→zot bridge.
-func newBridge(e *ext.Extension, logger *log.Logger) *bridge {
+func newBridge(e *ext.Extension, cwd string, logger *log.Logger) *bridge {
 	return &bridge{
 		e:       e,
+		cwd:     cwd,
 		servers: make(map[string]*managedServer),
 		mapping: make(map[string]toolMapping),
 		logger:  logger,
 // loadServers reads the config and creates managed servers.
 func (b *bridge) loadServers(cfg Config) {
 	for name, srvCfg := range cfg.MCPServers {
-		srv := newManagedServer(name, srvCfg, b.logger)
+		srv := newManagedServer(name, srvCfg, b.cwd, b.logger)
 		b.servers[name] = srv
 	}
 }

M examples/extensions/mcp-bridge/bridge_test.go +12 -0


@@ -12,6 +12,7 @@ import (
12	12
13	13		func testBridge() *bridge {
14	14		return &bridge{
	15	+	cwd: "/project",
15	16		servers: map[string]*managedServer{},
16	17		mapping: map[string]toolMapping{},
17	18		logger: log.New(io.Discard, "", 0),

@@ -30,6 +31,7 @@ func TestHandleToolCallStartFailureIsFriendlyError(t *testing.T) {
30	31		b := testBridge()
31	32		b.servers["bogus"] = newManagedServer("bogus",
32	33		ServerConfig{Transport: "no-such-transport", ConnectTimeout: 1, RequestTimeout: 1},
	34	+	"/project",
33	35		log.New(io.Discard, "", 0))
34	36		b.mapping["mcp__bogus__t"] = toolMapping{serverName: "bogus", mcpTool: "t"}
35	37

@@ -39,6 +41,16 @@ func TestHandleToolCallStartFailureIsFriendlyError(t *testing.T) {
39	41		}
40	42		}
41	43
	44	+	func TestLoadServersPassesProjectCWD(t *testing.T) {
	45	+	b := testBridge()
	46	+	b.loadServers(Config{MCPServers: map[string]ServerConfig{
	47	+	"fs": {Transport: "stdio", Command: "dummy"},
	48	+	}})
	49	+	if got := b.servers["fs"].cwd; got != "/project" {
	50	+	t.Fatalf("managed server cwd = %q, want /project", got)
	51	+	}
	52	+	}
	53	+
42	54		func TestClassifyTimeoutUsesErrorsIs(t *testing.T) {
43	55		wrapped := errors.Join(errors.New("call failed"), context.DeadlineExceeded)
44	56		if !errors.Is(wrapped, context.DeadlineExceeded) {


@@ -12,6 +12,7 @@ import (
12		12
13	func testBridge() *bridge {	13		func testBridge() *bridge {
14	return &bridge{	14		return &bridge{
		15	+	cwd: "/project",
15	servers: map[string]*managedServer{},	16		servers: map[string]*managedServer{},
16	mapping: map[string]toolMapping{},	17		mapping: map[string]toolMapping{},
17	logger: log.New(io.Discard, "", 0),	18		logger: log.New(io.Discard, "", 0),

@@ -30,6 +31,7 @@ func TestHandleToolCallStartFailureIsFriendlyError(t *testing.T) {
30	b := testBridge()	31		b := testBridge()
31	b.servers["bogus"] = newManagedServer("bogus",	32		b.servers["bogus"] = newManagedServer("bogus",
32	ServerConfig{Transport: "no-such-transport", ConnectTimeout: 1, RequestTimeout: 1},	33		ServerConfig{Transport: "no-such-transport", ConnectTimeout: 1, RequestTimeout: 1},
		34	+	"/project",
33	log.New(io.Discard, "", 0))	35		log.New(io.Discard, "", 0))
34	b.mapping["mcp__bogus__t"] = toolMapping{serverName: "bogus", mcpTool: "t"}	36		b.mapping["mcp__bogus__t"] = toolMapping{serverName: "bogus", mcpTool: "t"}
35		37

@@ -39,6 +41,16 @@ func TestHandleToolCallStartFailureIsFriendlyError(t *testing.T) {
39	}	41		}
40	}	42		}
41		43
		44	+	func TestLoadServersPassesProjectCWD(t *testing.T) {
		45	+	b := testBridge()
		46	+	b.loadServers(Config{MCPServers: map[string]ServerConfig{
		47	+	"fs": {Transport: "stdio", Command: "dummy"},
		48	+	}})
		49	+	if got := b.servers["fs"].cwd; got != "/project" {
		50	+	t.Fatalf("managed server cwd = %q, want /project", got)
		51	+	}
		52	+	}
		53	+
42	func TestClassifyTimeoutUsesErrorsIs(t *testing.T) {	54		func TestClassifyTimeoutUsesErrorsIs(t *testing.T) {
43	wrapped := errors.Join(errors.New("call failed"), context.DeadlineExceeded)	55		wrapped := errors.Join(errors.New("call failed"), context.DeadlineExceeded)
44	if !errors.Is(wrapped, context.DeadlineExceeded) {	56		if !errors.Is(wrapped, context.DeadlineExceeded) {

M examples/extensions/mcp-bridge/main.go +1 -1


@@ -76,7 +76,7 @@ func main() {
76	76
77	77		logger.Printf("found %d MCP server(s)", len(cfg.MCPServers))
78	78
79		-	b = newBridge(e, logger)
	79	+	b = newBridge(e, cwd, logger)
80	80		b.loadServers(cfg)
81	81
82	82		cachePath := toolCachePath()


@@ -76,7 +76,7 @@ func main() {
76			76
77		logger.Printf("found %d MCP server(s)", len(cfg.MCPServers))	77		logger.Printf("found %d MCP server(s)", len(cfg.MCPServers))
78			78
79	-	b = newBridge(e, logger)	79	+	b = newBridge(e, cwd, logger)
80		b.loadServers(cfg)	80		b.loadServers(cfg)
81			81
82		cachePath := toolCachePath()	82		cachePath := toolCachePath()

M examples/extensions/mcp-bridge/server.go +24 -3


@@ -16,6 +16,8 @@ import (
16	16		"fmt"
17	17		"io"
18	18		"log"
	19	+	"os"
	20	+	"os/exec"
19	21		"strings"
20	22		"sync"
21	23		"time"

@@ -54,6 +56,7 @@ func (s serverState) String() string {
54	56		type managedServer struct {
55	57		name string
56	58		config ServerConfig
	59	+	cwd string
57	60		logger *log.Logger
58	61
59	62		mu sync.Mutex

@@ -66,10 +69,11 @@ type managedServer struct {
66	69		}
67	70
68	71		// newManagedServer creates a new server wrapper.
69		-	func newManagedServer(name string, cfg ServerConfig, logger log.Logger) managedServer {
	72	+	func newManagedServer(name string, cfg ServerConfig, cwd string, logger log.Logger) managedServer {
70	73		return &managedServer{
71	74		name: name,
72	75		config: cfg,
	76	+	cwd: cwd,
73	77		logger: logger,
74	78		state: stateStopped,
75	79		lastUsed: time.Now(),

@@ -186,8 +190,25 @@ func (s managedServer) startStdio() (client.Client, error) {
186	190		env = append(env, fmt.Sprintf("%s=%s", k, v))
187	191		}
188	192
189		-	// Create stdio client (this spawns the subprocess)
190		-	c, err := client.NewStdioMCPClient(s.config.Command, env, s.config.Args...)
	193	+	// Create stdio client (this spawns the subprocess). Run stdio MCP
	194	+	// servers from the zot session's project directory, not the installed
	195	+	// extension directory. Many MCP servers use their process cwd as their
	196	+	// project root when answering relative-path or directory-listing
	197	+	// requests, so inheriting mcp-bridge's cwd makes them operate on the
	198	+	// extension install instead of the user's project.
	199	+	c, err := client.NewStdioMCPClientWithOptions(
	200	+	s.config.Command,
	201	+	env,
	202	+	s.config.Args,
	203	+	transport.WithCommandFunc(func(ctx context.Context, command string, env []string, args []string) (*exec.Cmd, error) {
	204	+	cmd := exec.CommandContext(ctx, command, args...)
	205	+	cmd.Env = append(os.Environ(), env...)
	206	+	if s.cwd != "" {
	207	+	cmd.Dir = s.cwd
	208	+	}
	209	+	return cmd, nil
	210	+	}),
	211	+	)
191	212		if err != nil {
192	213		return nil, fmt.Errorf("spawn %s: %w", s.config.Command, err)
193	214		}

 	"fmt"
 	"io"
 	"log"
+	"os"
+	"os/exec"
 	"strings"
 	"sync"
 	"time"
 type managedServer struct {
 	name   string
 	config ServerConfig
+	cwd    string
 	logger *log.Logger
 	mu       sync.Mutex
 }
 // newManagedServer creates a new server wrapper.
-func newManagedServer(name string, cfg ServerConfig, logger *log.Logger) *managedServer {
+func newManagedServer(name string, cfg ServerConfig, cwd string, logger *log.Logger) *managedServer {
 	return &managedServer{
 		name:     name,
 		config:   cfg,
+		cwd:      cwd,
 		logger:   logger,
 		state:    stateStopped,
 		lastUsed: time.Now(),
 		env = append(env, fmt.Sprintf("%s=%s", k, v))
 	}
-	// Create stdio client (this spawns the subprocess)
+	// Create stdio client (this spawns the subprocess). Run stdio MCP
-	c, err := client.NewStdioMCPClient(s.config.Command, env, s.config.Args...)
+	// servers from the zot session's project directory, not the installed
+	// extension directory. Many MCP servers use their process cwd as their
+	// project root when answering relative-path or directory-listing
+	// requests, so inheriting mcp-bridge's cwd makes them operate on the
+	// extension install instead of the user's project.
+	c, err := client.NewStdioMCPClientWithOptions(
+		s.config.Command,
+		env,
+		s.config.Args,
+		transport.WithCommandFunc(func(ctx context.Context, command string, env []string, args []string) (*exec.Cmd, error) {
+			cmd := exec.CommandContext(ctx, command, args...)
+			cmd.Env = append(os.Environ(), env...)
+			if s.cwd != "" {
+				cmd.Dir = s.cwd
+			}
+			return cmd, nil
+		}),
+	)
 	if err != nil {
 		return nil, fmt.Errorf("spawn %s: %w", s.config.Command, err)
 	}

M examples/extensions/mcp-bridge/status_test.go +9 -9


@@ -16,7 +16,7 @@ import (
16	16		)
17	17
18	18		func TestManagedServerStatusCompact(t *testing.T) {
19		-	s := newManagedServer("grep", ServerConfig{}, log.New(io.Discard, "", 0))
	19	+	s := newManagedServer("grep", ServerConfig{}, "", log.New(io.Discard, "", 0))
20	20
21	21		s.state = stateReady
22	22		s.tools = []mcp.Tool{{Name: "searchGitHub"}}

@@ -38,10 +38,10 @@ func TestManagedServerStatusCompact(t *testing.T) {
38	38
39	39		func TestFormatStatusSummaryCompact(t *testing.T) {
40	40		b := &bridge{servers: map[string]*managedServer{}}
41		-	b.servers["grep"] = newManagedServer("grep", ServerConfig{}, log.New(io.Discard, "", 0))
	41	+	b.servers["grep"] = newManagedServer("grep", ServerConfig{}, "", log.New(io.Discard, "", 0))
42	42		b.servers["grep"].state = stateReady
43	43		b.servers["grep"].tools = []mcp.Tool{{Name: "searchGitHub"}}
44		-	b.servers["n8n-mcp"] = newManagedServer("n8n-mcp", ServerConfig{}, log.New(io.Discard, "", 0))
	44	+	b.servers["n8n-mcp"] = newManagedServer("n8n-mcp", ServerConfig{}, "", log.New(io.Discard, "", 0))
45	45		b.servers["n8n-mcp"].state = stateReady
46	46		b.servers["n8n-mcp"].tools = make([]mcp.Tool, 26)
47	47

@@ -54,7 +54,7 @@ func TestFormatStatusSummaryCompact(t *testing.T) {
54	54		}
55	55
56	56		func TestManagedServerStopBeforeStartDoesNotPanic(t *testing.T) {
57		-	s := newManagedServer("never-started", ServerConfig{}, log.New(io.Discard, "", 0))
	57	+	s := newManagedServer("never-started", ServerConfig{}, "", log.New(io.Discard, "", 0))
58	58		s.stop()
59	59		if got, want := s.state, stateStopped; got != want {
60	60		t.Fatalf("state = %s, want %s", got, want)

@@ -98,10 +98,10 @@ func TestCompactErrShortensConnectionFailures(t *testing.T) {
98	98
99	99		func TestNotifyLevelWarnOnPartialFailure(t *testing.T) {
100	100		b := &bridge{servers: map[string]*managedServer{}}
101		-	b.servers["grep"] = newManagedServer("grep", ServerConfig{}, log.New(io.Discard, "", 0))
	101	+	b.servers["grep"] = newManagedServer("grep", ServerConfig{}, "", log.New(io.Discard, "", 0))
102	102		b.servers["grep"].state = stateReady
103	103		b.servers["grep"].tools = []mcp.Tool{{Name: "searchGitHub"}}
104		-	b.servers["broken"] = newManagedServer("broken", ServerConfig{}, log.New(io.Discard, "", 0))
	104	+	b.servers["broken"] = newManagedServer("broken", ServerConfig{}, "", log.New(io.Discard, "", 0))
105	105		b.servers["broken"].state = stateError
106	106		b.servers["broken"].startErr = errors.New("authorization required\nmore detail")
107	107

@@ -114,7 +114,7 @@ func TestNotifyLevelWarnOnPartialFailure(t *testing.T) {
114	114		}
115	115
116	116		func TestStopDuringStartDiscardsStaleResult(t *testing.T) {
117		-	s := newManagedServer("racy", ServerConfig{}, log.New(io.Discard, "", 0))
	117	+	s := newManagedServer("racy", ServerConfig{}, "", log.New(io.Discard, "", 0))
118	118
119	119		// Simulate the window inside start(): state is starting, gen recorded.
120	120		s.mu.Lock()

@@ -142,7 +142,7 @@ func TestStopDuringStartDiscardsStaleResult(t *testing.T) {
142	142		}
143	143
144	144		func TestCallToolNilClientReturnsErrorNotPanic(t *testing.T) {
145		-	s := newManagedServer("bogus", ServerConfig{Transport: "no-such-transport", RequestTimeout: 1, ConnectTimeout: 1}, log.New(io.Discard, "", 0))
	145	+	s := newManagedServer("bogus", ServerConfig{Transport: "no-such-transport", RequestTimeout: 1, ConnectTimeout: 1}, "", log.New(io.Discard, "", 0))
146	146		_, err := s.callTool(context.Background(), "anything", nil)
147	147		if err == nil {
148	148		t.Fatal("expected error from unknown transport")

@@ -151,7 +151,7 @@ func TestCallToolNilClientReturnsErrorNotPanic(t *testing.T) {
151	151
152	152		func TestPipeStderrKeepsLinesIntactAcrossChunks(t *testing.T) {
153	153		var buf bytes.Buffer
154		-	s := newManagedServer("srv", ServerConfig{}, log.New(&buf, "", 0))
	154	+	s := newManagedServer("srv", ServerConfig{}, "", log.New(&buf, "", 0))
155	155
156	156		// iotest.OneByteReader forces 1-byte reads: the old 4096-byte
157	157		// chunking code would log every byte as its own "line".


@@ -16,7 +16,7 @@ import (
16		)	16		)
17			17
18		func TestManagedServerStatusCompact(t *testing.T) {	18		func TestManagedServerStatusCompact(t *testing.T) {
19	-	s := newManagedServer("grep", ServerConfig{}, log.New(io.Discard, "", 0))	19	+	s := newManagedServer("grep", ServerConfig{}, "", log.New(io.Discard, "", 0))
20			20
21		s.state = stateReady	21		s.state = stateReady
22		s.tools = []mcp.Tool{{Name: "searchGitHub"}}	22		s.tools = []mcp.Tool{{Name: "searchGitHub"}}

@@ -38,10 +38,10 @@ func TestManagedServerStatusCompact(t *testing.T) {
38			38
39		func TestFormatStatusSummaryCompact(t *testing.T) {	39		func TestFormatStatusSummaryCompact(t *testing.T) {
40		b := &bridge{servers: map[string]*managedServer{}}	40		b := &bridge{servers: map[string]*managedServer{}}
41	-	b.servers["grep"] = newManagedServer("grep", ServerConfig{}, log.New(io.Discard, "", 0))	41	+	b.servers["grep"] = newManagedServer("grep", ServerConfig{}, "", log.New(io.Discard, "", 0))
42		b.servers["grep"].state = stateReady	42		b.servers["grep"].state = stateReady
43		b.servers["grep"].tools = []mcp.Tool{{Name: "searchGitHub"}}	43		b.servers["grep"].tools = []mcp.Tool{{Name: "searchGitHub"}}
44	-	b.servers["n8n-mcp"] = newManagedServer("n8n-mcp", ServerConfig{}, log.New(io.Discard, "", 0))	44	+	b.servers["n8n-mcp"] = newManagedServer("n8n-mcp", ServerConfig{}, "", log.New(io.Discard, "", 0))
45		b.servers["n8n-mcp"].state = stateReady	45		b.servers["n8n-mcp"].state = stateReady
46		b.servers["n8n-mcp"].tools = make([]mcp.Tool, 26)	46		b.servers["n8n-mcp"].tools = make([]mcp.Tool, 26)
47			47

@@ -54,7 +54,7 @@ func TestFormatStatusSummaryCompact(t *testing.T) {
54		}	54		}
55			55
56		func TestManagedServerStopBeforeStartDoesNotPanic(t *testing.T) {	56		func TestManagedServerStopBeforeStartDoesNotPanic(t *testing.T) {
57	-	s := newManagedServer("never-started", ServerConfig{}, log.New(io.Discard, "", 0))	57	+	s := newManagedServer("never-started", ServerConfig{}, "", log.New(io.Discard, "", 0))
58		s.stop()	58		s.stop()
59		if got, want := s.state, stateStopped; got != want {	59		if got, want := s.state, stateStopped; got != want {
60		t.Fatalf("state = %s, want %s", got, want)	60		t.Fatalf("state = %s, want %s", got, want)

@@ -98,10 +98,10 @@ func TestCompactErrShortensConnectionFailures(t *testing.T) {
98			98
99		func TestNotifyLevelWarnOnPartialFailure(t *testing.T) {	99		func TestNotifyLevelWarnOnPartialFailure(t *testing.T) {
100		b := &bridge{servers: map[string]*managedServer{}}	100		b := &bridge{servers: map[string]*managedServer{}}
101	-	b.servers["grep"] = newManagedServer("grep", ServerConfig{}, log.New(io.Discard, "", 0))	101	+	b.servers["grep"] = newManagedServer("grep", ServerConfig{}, "", log.New(io.Discard, "", 0))
102		b.servers["grep"].state = stateReady	102		b.servers["grep"].state = stateReady
103		b.servers["grep"].tools = []mcp.Tool{{Name: "searchGitHub"}}	103		b.servers["grep"].tools = []mcp.Tool{{Name: "searchGitHub"}}
104	-	b.servers["broken"] = newManagedServer("broken", ServerConfig{}, log.New(io.Discard, "", 0))	104	+	b.servers["broken"] = newManagedServer("broken", ServerConfig{}, "", log.New(io.Discard, "", 0))
105		b.servers["broken"].state = stateError	105		b.servers["broken"].state = stateError
106		b.servers["broken"].startErr = errors.New("authorization required\nmore detail")	106		b.servers["broken"].startErr = errors.New("authorization required\nmore detail")
107			107

@@ -114,7 +114,7 @@ func TestNotifyLevelWarnOnPartialFailure(t *testing.T) {
114		}	114		}
115			115
116		func TestStopDuringStartDiscardsStaleResult(t *testing.T) {	116		func TestStopDuringStartDiscardsStaleResult(t *testing.T) {
117	-	s := newManagedServer("racy", ServerConfig{}, log.New(io.Discard, "", 0))	117	+	s := newManagedServer("racy", ServerConfig{}, "", log.New(io.Discard, "", 0))
118			118
119		// Simulate the window inside start(): state is starting, gen recorded.	119		// Simulate the window inside start(): state is starting, gen recorded.
120		s.mu.Lock()	120		s.mu.Lock()

@@ -142,7 +142,7 @@ func TestStopDuringStartDiscardsStaleResult(t *testing.T) {
142		}	142		}
143			143
144		func TestCallToolNilClientReturnsErrorNotPanic(t *testing.T) {	144		func TestCallToolNilClientReturnsErrorNotPanic(t *testing.T) {
145	-	s := newManagedServer("bogus", ServerConfig{Transport: "no-such-transport", RequestTimeout: 1, ConnectTimeout: 1}, log.New(io.Discard, "", 0))	145	+	s := newManagedServer("bogus", ServerConfig{Transport: "no-such-transport", RequestTimeout: 1, ConnectTimeout: 1}, "", log.New(io.Discard, "", 0))
146		_, err := s.callTool(context.Background(), "anything", nil)	146		_, err := s.callTool(context.Background(), "anything", nil)
147		if err == nil {	147		if err == nil {
148		t.Fatal("expected error from unknown transport")	148		t.Fatal("expected error from unknown transport")

@@ -151,7 +151,7 @@ func TestCallToolNilClientReturnsErrorNotPanic(t *testing.T) {
151			151
152		func TestPipeStderrKeepsLinesIntactAcrossChunks(t *testing.T) {	152		func TestPipeStderrKeepsLinesIntactAcrossChunks(t *testing.T) {
153		var buf bytes.Buffer	153		var buf bytes.Buffer
154	-	s := newManagedServer("srv", ServerConfig{}, log.New(&buf, "", 0))	154	+	s := newManagedServer("srv", ServerConfig{}, "", log.New(&buf, "", 0))
155			155
156		// iotest.OneByteReader forces 1-byte reads: the old 4096-byte	156		// iotest.OneByteReader forces 1-byte reads: the old 4096-byte
157		// chunking code would log every byte as its own "line".	157		// chunking code would log every byte as its own "line".