diff --git a/cmd/gitea-mcp/main.go b/cmd/gitea-mcp/main.go
index a80bd7a..b565fb7 100644
--- a/cmd/gitea-mcp/main.go
+++ b/cmd/gitea-mcp/main.go
@@ -92,8 +92,10 @@ func main() {
 
 	mux := http.NewServeMux()
 	mux.Handle("/mcp", mcp.OriginAllowlist(cfg.OriginAllowlist)(
-		chassisauth.BearerMiddleware(cfg.StaticToken, jwtValidator, "gitea", resourceMetadataURL,
-			auth.CallerMiddleware(logger, mcpSrv),
+		auth.PassthroughMiddleware(giteaClient, mcpSrv,
+			chassisauth.BearerMiddleware(cfg.StaticToken, jwtValidator, "gitea", resourceMetadataURL,
+				auth.CallerMiddleware(logger, mcpSrv),
+			),
 		),
 	))
 	mux.Handle("/healthz", newHealthzHandler(cfg.DexIssuerURL != "", jwtValidator != nil, jwtInitErr))
diff --git a/internal/auth/caller.go b/internal/auth/caller.go
index 77a2005..a301428 100644
--- a/internal/auth/caller.go
+++ b/internal/auth/caller.go
@@ -36,11 +36,14 @@ func CallerMiddleware(logger *slog.Logger, next http.Handler) http.Handler {
 				"x_forwarded_user", fwdUser)
 		}
 
-		ctx := context.WithValue(r.Context(), ctxKey{}, user)
-		next.ServeHTTP(w, r.WithContext(ctx))
+		next.ServeHTTP(w, r.WithContext(withCaller(r.Context(), user)))
 	})
 }
 
+func withCaller(ctx context.Context, user string) context.Context {
+	return context.WithValue(ctx, ctxKey{}, user)
+}
+
 func Caller(ctx context.Context) string {
 	if v, ok := ctx.Value(ctxKey{}).(string); ok {
 		return v
diff --git a/internal/auth/passthrough.go b/internal/auth/passthrough.go
new file mode 100644
index 0000000..ba6efc0
--- /dev/null
+++ b/internal/auth/passthrough.go
@@ -0,0 +1,36 @@
+package auth
+
+import (
+	"context"
+	"net/http"
+	"strings"
+
+	"git.d-ma.be/mathias/gitea-mcp/internal/gitea"
+)
+
+// TokenValidator asks the upstream service who a bearer token belongs to.
+type TokenValidator interface {
+	ValidateToken(ctx context.Context, token string) (username string, ok bool)
+}
+
+// PassthroughMiddleware lets a caller authenticate with their own Gitea PAT:
+// if the request's bearer token validates directly against Gitea, it's used
+// as-is for every upstream call this request makes (gitea-mcp#59), instead of
+// the server's shared default token. Any other bearer (static token, JWT, or
+// none) falls through to fallback unchanged — this only adds a capability, it
+// never removes the existing auth paths.
+func PassthroughMiddleware(validator TokenValidator, onValid, fallback http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		authz := r.Header.Get("Authorization")
+		token, hasBearer := strings.CutPrefix(authz, "Bearer ")
+		if hasBearer && token != "" {
+			if login, ok := validator.ValidateToken(r.Context(), token); ok {
+				ctx := withCaller(r.Context(), login)
+				ctx = gitea.WithToken(ctx, token)
+				onValid.ServeHTTP(w, r.WithContext(ctx))
+				return
+			}
+		}
+		fallback.ServeHTTP(w, r)
+	})
+}
diff --git a/internal/auth/passthrough_test.go b/internal/auth/passthrough_test.go
new file mode 100644
index 0000000..0234022
--- /dev/null
+++ b/internal/auth/passthrough_test.go
@@ -0,0 +1,82 @@
+package auth_test
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"git.d-ma.be/mathias/gitea-mcp/internal/auth"
+	"git.d-ma.be/mathias/gitea-mcp/internal/gitea"
+	"github.com/stretchr/testify/assert"
+)
+
+type fakeValidator struct {
+	login string
+	ok    bool
+	calls int
+}
+
+func (f *fakeValidator) ValidateToken(_ context.Context, _ string) (string, bool) {
+	f.calls++
+	return f.login, f.ok
+}
+
+func TestPassthroughMiddleware_ValidPATGoesStraightToOnValid(t *testing.T) {
+	validator := &fakeValidator{login: "alice", ok: true}
+	var gotCaller string
+	var gotToken string
+	var gotOK bool
+	onValid := http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
+		gotCaller = auth.Caller(r.Context())
+		gotToken, gotOK = gitea.TokenFromContext(r.Context())
+	})
+	fallback := http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
+		t.Fatal("fallback should not be called for a valid PAT")
+	})
+
+	h := auth.PassthroughMiddleware(validator, onValid, fallback)
+	req := httptest.NewRequest(http.MethodPost, "/mcp", nil)
+	req.Header.Set("Authorization", "Bearer alices-pat")
+	h.ServeHTTP(httptest.NewRecorder(), req)
+
+	assert.Equal(t, "alice", gotCaller)
+	assert.True(t, gotOK)
+	assert.Equal(t, "alices-pat", gotToken)
+}
+
+func TestPassthroughMiddleware_InvalidTokenFallsThrough(t *testing.T) {
+	validator := &fakeValidator{ok: false}
+	fallbackCalled := false
+	onValid := http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
+		t.Fatal("onValid should not be called for an invalid token")
+	})
+	fallback := http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
+		fallbackCalled = true
+	})
+
+	h := auth.PassthroughMiddleware(validator, onValid, fallback)
+	req := httptest.NewRequest(http.MethodPost, "/mcp", nil)
+	req.Header.Set("Authorization", "Bearer not-a-gitea-pat")
+	h.ServeHTTP(httptest.NewRecorder(), req)
+
+	assert.True(t, fallbackCalled)
+}
+
+func TestPassthroughMiddleware_NoBearerFallsThroughWithoutCallingValidator(t *testing.T) {
+	validator := &fakeValidator{ok: true, login: "alice"}
+	fallbackCalled := false
+	onValid := http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
+		t.Fatal("onValid should not be called with no Authorization header")
+	})
+	fallback := http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
+		fallbackCalled = true
+	})
+
+	h := auth.PassthroughMiddleware(validator, onValid, fallback)
+	req := httptest.NewRequest(http.MethodPost, "/mcp", nil)
+	h.ServeHTTP(httptest.NewRecorder(), req)
+
+	assert.True(t, fallbackCalled)
+	assert.Equal(t, 0, validator.calls, "validator should not be invoked when there's no bearer to check")
+}
diff --git a/internal/gitea/client.go b/internal/gitea/client.go
index fa8da6d..f467a13 100644
--- a/internal/gitea/client.go
+++ b/internal/gitea/client.go
@@ -3,6 +3,7 @@ package gitea
 import (
 	"bytes"
 	"context"
+	"encoding/json"
 	"fmt"
 	"io"
 	"net/http"
@@ -19,6 +20,21 @@ type Client struct {
 	branchCache *expirable.LRU[string, string]
 }
 
+type ctxTokenKey struct{}
+
+// WithToken overrides the token used for upstream Gitea calls made with the
+// returned context, taking precedence over the Client's configured default
+// token. Used for per-caller PAT pass-through (gitea-mcp#59).
+func WithToken(ctx context.Context, token string) context.Context {
+	return context.WithValue(ctx, ctxTokenKey{}, token)
+}
+
+// TokenFromContext returns the token set by WithToken, if any.
+func TokenFromContext(ctx context.Context) (string, bool) {
+	v, ok := ctx.Value(ctxTokenKey{}).(string)
+	return v, ok
+}
+
 func NewClient(baseURL, token string) *Client {
 	return &Client{
 		baseURL:     baseURL,
@@ -28,6 +44,23 @@ func NewClient(baseURL, token string) *Client {
 	}
 }
 
+// ValidateToken asks Gitea who a given token belongs to (GET /api/v1/user
+// using that token, not the client's configured default token) and returns
+// its login name. Used for per-caller PAT pass-through (gitea-mcp#59).
+func (c *Client) ValidateToken(ctx context.Context, token string) (string, bool) {
+	body, status, err := c.doOnce(WithToken(ctx, token), http.MethodGet, "/api/v1/user", nil)
+	if err != nil || status != http.StatusOK {
+		return "", false
+	}
+	var user struct {
+		Login string `json:"login"`
+	}
+	if err := json.Unmarshal(body, &user); err != nil || user.Login == "" {
+		return "", false
+	}
+	return user.Login, true
+}
+
 // DefaultBranch returns the default branch for a repo. Cached for 60s.
 func (c *Client) DefaultBranch(ctx context.Context, owner, name string) (string, error) {
 	key := owner + "/" + name
@@ -66,6 +99,9 @@ func (c *Client) doOnce(ctx context.Context, method, path string, body []byte) (
 		return nil, 0, err
 	}
 	token := c.token
+	if override, ok := TokenFromContext(ctx); ok {
+		token = override
+	}
 	if token != "" {
 		req.Header.Set("Authorization", "token "+token)
 	}
@@ -135,6 +171,9 @@ func (c *Client) doRaw(ctx context.Context, method, path string, body []byte) (*
 		return nil, err
 	}
 	token := c.token
+	if override, ok := TokenFromContext(ctx); ok {
+		token = override
+	}
 	if token != "" {
 		req.Header.Set("Authorization", "token "+token)
 	}
diff --git a/internal/gitea/client_test.go b/internal/gitea/client_test.go
index 84ff7d7..adc2f93 100644
--- a/internal/gitea/client_test.go
+++ b/internal/gitea/client_test.go
@@ -50,6 +50,49 @@ func TestRetryOn5xxGetSucceedsOnSecondAttempt(t *testing.T) {
 	assert.Equal(t, int32(2), atomic.LoadInt32(&attempts))
 }
 
+func TestClientPrefersTokenFromContextOverDefaultToken(t *testing.T) {
+	var gotAuth string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotAuth = r.Header.Get("Authorization")
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"ok":true}`))
+	}))
+	defer srv.Close()
+
+	c := gitea.NewClient(srv.URL, "default-token")
+	ctx := gitea.WithToken(context.Background(), "caller-token")
+	_, status, err := c.GetJSON(ctx, "/api/v1/user")
+	require.NoError(t, err)
+	assert.Equal(t, 200, status)
+	assert.Equal(t, "token caller-token", gotAuth)
+}
+
+func TestValidateTokenReturnsLoginOnSuccess(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "token candidate-token", r.Header.Get("Authorization"))
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"login":"alice"}`))
+	}))
+	defer srv.Close()
+
+	c := gitea.NewClient(srv.URL, "default-token")
+	login, ok := c.ValidateToken(context.Background(), "candidate-token")
+	assert.True(t, ok)
+	assert.Equal(t, "alice", login)
+}
+
+func TestValidateTokenReturnsFalseOn401(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		http.Error(w, "unauthorized", http.StatusUnauthorized)
+	}))
+	defer srv.Close()
+
+	c := gitea.NewClient(srv.URL, "default-token")
+	login, ok := c.ValidateToken(context.Background(), "bad-token")
+	assert.False(t, ok)
+	assert.Empty(t, login)
+}
+
 func TestRetryOnPostNotRetried(t *testing.T) {
 	var attempts int32
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {