Fix project isolation: Make loadChatHistory respect active project sessions

- Modified loadChatHistory() to check for active project before fetching all sessions
- When active project exists, use project.sessions instead of fetching from API
- Added detailed console logging to debug session filtering
- This prevents ALL sessions from appearing in every project's sidebar

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.venv/lib/python3.11/site-packages/mcp/server/auth/handlers/__init__.py

@@ -0,0 +1,3 @@
+"""
+Request handlers for MCP authorization endpoints.
+"""

.venv/lib/python3.11/site-packages/mcp/server/auth/handlers/authorize.py

@@ -0,0 +1,224 @@
+import logging
+from dataclasses import dataclass
+from typing import Any, Literal
+
+from pydantic import AnyUrl, BaseModel, Field, RootModel, ValidationError
+from starlette.datastructures import FormData, QueryParams
+from starlette.requests import Request
+from starlette.responses import RedirectResponse, Response
+
+from mcp.server.auth.errors import stringify_pydantic_error
+from mcp.server.auth.json_response import PydanticJSONResponse
+from mcp.server.auth.provider import (
+    AuthorizationErrorCode,
+    AuthorizationParams,
+    AuthorizeError,
+    OAuthAuthorizationServerProvider,
+    construct_redirect_uri,
+)
+from mcp.shared.auth import InvalidRedirectUriError, InvalidScopeError
+
+logger = logging.getLogger(__name__)
+
+
+class AuthorizationRequest(BaseModel):
+    # See https://datatracker.ietf.org/doc/html/rfc6749#section-4.1.1
+    client_id: str = Field(..., description="The client ID")
+    redirect_uri: AnyUrl | None = Field(None, description="URL to redirect to after authorization")
+
+    # see OAuthClientMetadata; we only support `code`
+    response_type: Literal["code"] = Field(..., description="Must be 'code' for authorization code flow")
+    code_challenge: str = Field(..., description="PKCE code challenge")
+    code_challenge_method: Literal["S256"] = Field("S256", description="PKCE code challenge method, must be S256")
+    state: str | None = Field(None, description="Optional state parameter")
+    scope: str | None = Field(
+        None,
+        description="Optional scope; if specified, should be a space-separated list of scope strings",
+    )
+    resource: str | None = Field(
+        None,
+        description="RFC 8707 resource indicator - the MCP server this token will be used with",
+    )
+
+
+class AuthorizationErrorResponse(BaseModel):
+    error: AuthorizationErrorCode
+    error_description: str | None
+    error_uri: AnyUrl | None = None
+    # must be set if provided in the request
+    state: str | None = None
+
+
+def best_effort_extract_string(key: str, params: None | FormData | QueryParams) -> str | None:
+    if params is None:  # pragma: no cover
+        return None
+    value = params.get(key)
+    if isinstance(value, str):
+        return value
+    return None
+
+
+class AnyUrlModel(RootModel[AnyUrl]):
+    root: AnyUrl
+
+
+@dataclass
+class AuthorizationHandler:
+    provider: OAuthAuthorizationServerProvider[Any, Any, Any]
+
+    async def handle(self, request: Request) -> Response:
+        # implements authorization requests for grant_type=code;
+        # see https://datatracker.ietf.org/doc/html/rfc6749#section-4.1.1
+
+        state = None
+        redirect_uri = None
+        client = None
+        params = None
+
+        async def error_response(
+            error: AuthorizationErrorCode,
+            error_description: str | None,
+            attempt_load_client: bool = True,
+        ):
+            # Error responses take two different formats:
+            # 1. The request has a valid client ID & redirect_uri: we issue a redirect
+            #    back to the redirect_uri with the error response fields as query
+            #    parameters. This allows the client to be notified of the error.
+            # 2. Otherwise, we return an error response directly to the end user;
+            #     we choose to do so in JSON, but this is left undefined in the
+            #     specification.
+            # See https://datatracker.ietf.org/doc/html/rfc6749#section-4.1.2.1
+            #
+            # This logic is a bit awkward to handle, because the error might be thrown
+            # very early in request validation, before we've done the usual Pydantic
+            # validation, loaded the client, etc. To handle this, error_response()
+            # contains fallback logic which attempts to load the parameters directly
+            # from the request.
+
+            nonlocal client, redirect_uri, state
+            if client is None and attempt_load_client:
+                # make last-ditch attempt to load the client
+                client_id = best_effort_extract_string("client_id", params)
+                client = await self.provider.get_client(client_id) if client_id else None
+            if redirect_uri is None and client:
+                # make last-ditch effort to load the redirect uri
+                try:
+                    if params is not None and "redirect_uri" not in params:
+                        raw_redirect_uri = None
+                    else:
+                        raw_redirect_uri = AnyUrlModel.model_validate(
+                            best_effort_extract_string("redirect_uri", params)
+                        ).root
+                    redirect_uri = client.validate_redirect_uri(raw_redirect_uri)
+                except (ValidationError, InvalidRedirectUriError):
+                    # if the redirect URI is invalid, ignore it & just return the
+                    # initial error
+                    pass
+
+            # the error response MUST contain the state specified by the client, if any
+            if state is None:  # pragma: no cover
+                # make last-ditch effort to load state
+                state = best_effort_extract_string("state", params)
+
+            error_resp = AuthorizationErrorResponse(
+                error=error,
+                error_description=error_description,
+                state=state,
+            )
+
+            if redirect_uri and client:
+                return RedirectResponse(
+                    url=construct_redirect_uri(str(redirect_uri), **error_resp.model_dump(exclude_none=True)),
+                    status_code=302,
+                    headers={"Cache-Control": "no-store"},
+                )
+            else:
+                return PydanticJSONResponse(
+                    status_code=400,
+                    content=error_resp,
+                    headers={"Cache-Control": "no-store"},
+                )
+
+        try:
+            # Parse request parameters
+            if request.method == "GET":
+                # Convert query_params to dict for pydantic validation
+                params = request.query_params
+            else:
+                # Parse form data for POST requests
+                params = await request.form()
+
+            # Save state if it exists, even before validation
+            state = best_effort_extract_string("state", params)
+
+            try:
+                auth_request = AuthorizationRequest.model_validate(params)
+                state = auth_request.state  # Update with validated state
+            except ValidationError as validation_error:
+                error: AuthorizationErrorCode = "invalid_request"
+                for e in validation_error.errors():
+                    if e["loc"] == ("response_type",) and e["type"] == "literal_error":
+                        error = "unsupported_response_type"
+                        break
+                return await error_response(error, stringify_pydantic_error(validation_error))
+
+            # Get client information
+            client = await self.provider.get_client(
+                auth_request.client_id,
+            )
+            if not client:
+                # For client_id validation errors, return direct error (no redirect)
+                return await error_response(
+                    error="invalid_request",
+                    error_description=f"Client ID '{auth_request.client_id}' not found",
+                    attempt_load_client=False,
+                )
+
+            # Validate redirect_uri against client's registered URIs
+            try:
+                redirect_uri = client.validate_redirect_uri(auth_request.redirect_uri)
+            except InvalidRedirectUriError as validation_error:
+                # For redirect_uri validation errors, return direct error (no redirect)
+                return await error_response(
+                    error="invalid_request",
+                    error_description=validation_error.message,
+                )
+
+            # Validate scope - for scope errors, we can redirect
+            try:
+                scopes = client.validate_scope(auth_request.scope)
+            except InvalidScopeError as validation_error:
+                # For scope errors, redirect with error parameters
+                return await error_response(
+                    error="invalid_scope",
+                    error_description=validation_error.message,
+                )
+
+            # Setup authorization parameters
+            auth_params = AuthorizationParams(
+                state=state,
+                scopes=scopes,
+                code_challenge=auth_request.code_challenge,
+                redirect_uri=redirect_uri,
+                redirect_uri_provided_explicitly=auth_request.redirect_uri is not None,
+                resource=auth_request.resource,  # RFC 8707
+            )
+
+            try:
+                # Let the provider pick the next URI to redirect to
+                return RedirectResponse(
+                    url=await self.provider.authorize(
+                        client,
+                        auth_params,
+                    ),
+                    status_code=302,
+                    headers={"Cache-Control": "no-store"},
+                )
+            except AuthorizeError as e:
+                # Handle authorization errors as defined in RFC 6749 Section 4.1.2.1
+                return await error_response(error=e.error, error_description=e.error_description)
+
+        except Exception as validation_error:  # pragma: no cover
+            # Catch-all for unexpected errors
+            logger.exception("Unexpected error in authorization_handler", exc_info=validation_error)
+            return await error_response(error="server_error", error_description="An unexpected error occurred")

.venv/lib/python3.11/site-packages/mcp/server/auth/handlers/metadata.py

@@ -0,0 +1,29 @@
+from dataclasses import dataclass
+
+from starlette.requests import Request
+from starlette.responses import Response
+
+from mcp.server.auth.json_response import PydanticJSONResponse
+from mcp.shared.auth import OAuthMetadata, ProtectedResourceMetadata
+
+
+@dataclass
+class MetadataHandler:
+    metadata: OAuthMetadata
+
+    async def handle(self, request: Request) -> Response:
+        return PydanticJSONResponse(
+            content=self.metadata,
+            headers={"Cache-Control": "public, max-age=3600"},  # Cache for 1 hour
+        )
+
+
+@dataclass
+class ProtectedResourceMetadataHandler:
+    metadata: ProtectedResourceMetadata
+
+    async def handle(self, request: Request) -> Response:
+        return PydanticJSONResponse(
+            content=self.metadata,
+            headers={"Cache-Control": "public, max-age=3600"},  # Cache for 1 hour
+        )

.venv/lib/python3.11/site-packages/mcp/server/auth/handlers/register.py

@@ -0,0 +1,136 @@
+import secrets
+import time
+from dataclasses import dataclass
+from typing import Any
+from uuid import uuid4
+
+from pydantic import BaseModel, RootModel, ValidationError
+from starlette.requests import Request
+from starlette.responses import Response
+
+from mcp.server.auth.errors import stringify_pydantic_error
+from mcp.server.auth.json_response import PydanticJSONResponse
+from mcp.server.auth.provider import OAuthAuthorizationServerProvider, RegistrationError, RegistrationErrorCode
+from mcp.server.auth.settings import ClientRegistrationOptions
+from mcp.shared.auth import OAuthClientInformationFull, OAuthClientMetadata
+
+
+class RegistrationRequest(RootModel[OAuthClientMetadata]):
+    # this wrapper is a no-op; it's just to separate out the types exposed to the
+    # provider from what we use in the HTTP handler
+    root: OAuthClientMetadata
+
+
+class RegistrationErrorResponse(BaseModel):
+    error: RegistrationErrorCode
+    error_description: str | None
+
+
+@dataclass
+class RegistrationHandler:
+    provider: OAuthAuthorizationServerProvider[Any, Any, Any]
+    options: ClientRegistrationOptions
+
+    async def handle(self, request: Request) -> Response:
+        # Implements dynamic client registration as defined in https://datatracker.ietf.org/doc/html/rfc7591#section-3.1
+        try:
+            # Parse request body as JSON
+            body = await request.json()
+            client_metadata = OAuthClientMetadata.model_validate(body)
+
+            # Scope validation is handled below
+        except ValidationError as validation_error:
+            return PydanticJSONResponse(
+                content=RegistrationErrorResponse(
+                    error="invalid_client_metadata",
+                    error_description=stringify_pydantic_error(validation_error),
+                ),
+                status_code=400,
+            )
+
+        client_id = str(uuid4())
+
+        # If auth method is None, default to client_secret_post
+        if client_metadata.token_endpoint_auth_method is None:
+            client_metadata.token_endpoint_auth_method = "client_secret_post"
+
+        client_secret = None
+        if client_metadata.token_endpoint_auth_method != "none":  # pragma: no branch
+            # cryptographically secure random 32-byte hex string
+            client_secret = secrets.token_hex(32)
+
+        if client_metadata.scope is None and self.options.default_scopes is not None:
+            client_metadata.scope = " ".join(self.options.default_scopes)
+        elif client_metadata.scope is not None and self.options.valid_scopes is not None:
+            requested_scopes = set(client_metadata.scope.split())
+            valid_scopes = set(self.options.valid_scopes)
+            if not requested_scopes.issubset(valid_scopes):  # pragma: no branch
+                return PydanticJSONResponse(
+                    content=RegistrationErrorResponse(
+                        error="invalid_client_metadata",
+                        error_description="Requested scopes are not valid: "
+                        f"{', '.join(requested_scopes - valid_scopes)}",
+                    ),
+                    status_code=400,
+                )
+        if not {"authorization_code", "refresh_token"}.issubset(set(client_metadata.grant_types)):
+            return PydanticJSONResponse(
+                content=RegistrationErrorResponse(
+                    error="invalid_client_metadata",
+                    error_description="grant_types must be authorization_code and refresh_token",
+                ),
+                status_code=400,
+            )
+
+        # The MCP spec requires servers to use the authorization `code` flow
+        # with PKCE
+        if "code" not in client_metadata.response_types:
+            return PydanticJSONResponse(
+                content=RegistrationErrorResponse(
+                    error="invalid_client_metadata",
+                    error_description="response_types must include 'code' for authorization_code grant",
+                ),
+                status_code=400,
+            )
+
+        client_id_issued_at = int(time.time())
+        client_secret_expires_at = (
+            client_id_issued_at + self.options.client_secret_expiry_seconds
+            if self.options.client_secret_expiry_seconds is not None
+            else None
+        )
+
+        client_info = OAuthClientInformationFull(
+            client_id=client_id,
+            client_id_issued_at=client_id_issued_at,
+            client_secret=client_secret,
+            client_secret_expires_at=client_secret_expires_at,
+            # passthrough information from the client request
+            redirect_uris=client_metadata.redirect_uris,
+            token_endpoint_auth_method=client_metadata.token_endpoint_auth_method,
+            grant_types=client_metadata.grant_types,
+            response_types=client_metadata.response_types,
+            client_name=client_metadata.client_name,
+            client_uri=client_metadata.client_uri,
+            logo_uri=client_metadata.logo_uri,
+            scope=client_metadata.scope,
+            contacts=client_metadata.contacts,
+            tos_uri=client_metadata.tos_uri,
+            policy_uri=client_metadata.policy_uri,
+            jwks_uri=client_metadata.jwks_uri,
+            jwks=client_metadata.jwks,
+            software_id=client_metadata.software_id,
+            software_version=client_metadata.software_version,
+        )
+        try:
+            # Register client
+            await self.provider.register_client(client_info)
+
+            # Return client information
+            return PydanticJSONResponse(content=client_info, status_code=201)
+        except RegistrationError as e:
+            # Handle registration errors as defined in RFC 7591 Section 3.2.2
+            return PydanticJSONResponse(
+                content=RegistrationErrorResponse(error=e.error, error_description=e.error_description),
+                status_code=400,
+            )

.venv/lib/python3.11/site-packages/mcp/server/auth/handlers/revoke.py

@@ -0,0 +1,91 @@
+from dataclasses import dataclass
+from functools import partial
+from typing import Any, Literal
+
+from pydantic import BaseModel, ValidationError
+from starlette.requests import Request
+from starlette.responses import Response
+
+from mcp.server.auth.errors import (
+    stringify_pydantic_error,
+)
+from mcp.server.auth.json_response import PydanticJSONResponse
+from mcp.server.auth.middleware.client_auth import AuthenticationError, ClientAuthenticator
+from mcp.server.auth.provider import AccessToken, OAuthAuthorizationServerProvider, RefreshToken
+
+
+class RevocationRequest(BaseModel):
+    """
+    # See https://datatracker.ietf.org/doc/html/rfc7009#section-2.1
+    """
+
+    token: str
+    token_type_hint: Literal["access_token", "refresh_token"] | None = None
+    client_id: str
+    client_secret: str | None
+
+
+class RevocationErrorResponse(BaseModel):
+    error: Literal["invalid_request", "unauthorized_client"]
+    error_description: str | None = None
+
+
+@dataclass
+class RevocationHandler:
+    provider: OAuthAuthorizationServerProvider[Any, Any, Any]
+    client_authenticator: ClientAuthenticator
+
+    async def handle(self, request: Request) -> Response:
+        """
+        Handler for the OAuth 2.0 Token Revocation endpoint.
+        """
+        try:
+            client = await self.client_authenticator.authenticate_request(request)
+        except AuthenticationError as e:  # pragma: no cover
+            return PydanticJSONResponse(
+                status_code=401,
+                content=RevocationErrorResponse(
+                    error="unauthorized_client",
+                    error_description=e.message,
+                ),
+            )
+
+        try:
+            form_data = await request.form()
+            revocation_request = RevocationRequest.model_validate(dict(form_data))
+        except ValidationError as e:
+            return PydanticJSONResponse(
+                status_code=400,
+                content=RevocationErrorResponse(
+                    error="invalid_request",
+                    error_description=stringify_pydantic_error(e),
+                ),
+            )
+
+        loaders = [
+            self.provider.load_access_token,
+            partial(self.provider.load_refresh_token, client),
+        ]
+        if revocation_request.token_type_hint == "refresh_token":  # pragma: no cover
+            loaders = reversed(loaders)
+
+        token: None | AccessToken | RefreshToken = None
+        for loader in loaders:
+            token = await loader(revocation_request.token)
+            if token is not None:
+                break
+
+        # if token is not found, just return HTTP 200 per the RFC
+        if token and token.client_id == client.client_id:
+            # Revoke token; provider is not meant to be able to do validation
+            # at this point that would result in an error
+            await self.provider.revoke_token(token)
+
+        # Return successful empty response
+        return Response(
+            status_code=200,
+            headers={
+                "Cache-Control": "no-store",
+                "Pragma": "no-cache",
+            },
+        )

.venv/lib/python3.11/site-packages/mcp/server/auth/handlers/token.py

@@ -0,0 +1,241 @@
+import base64
+import hashlib
+import time
+from dataclasses import dataclass
+from typing import Annotated, Any, Literal
+
+from pydantic import AnyHttpUrl, AnyUrl, BaseModel, Field, RootModel, ValidationError
+from starlette.requests import Request
+
+from mcp.server.auth.errors import stringify_pydantic_error
+from mcp.server.auth.json_response import PydanticJSONResponse
+from mcp.server.auth.middleware.client_auth import AuthenticationError, ClientAuthenticator
+from mcp.server.auth.provider import OAuthAuthorizationServerProvider, TokenError, TokenErrorCode
+from mcp.shared.auth import OAuthToken
+
+
+class AuthorizationCodeRequest(BaseModel):
+    # See https://datatracker.ietf.org/doc/html/rfc6749#section-4.1.3
+    grant_type: Literal["authorization_code"]
+    code: str = Field(..., description="The authorization code")
+    redirect_uri: AnyUrl | None = Field(None, description="Must be the same as redirect URI provided in /authorize")
+    client_id: str
+    # we use the client_secret param, per https://datatracker.ietf.org/doc/html/rfc6749#section-2.3.1
+    client_secret: str | None = None
+    # See https://datatracker.ietf.org/doc/html/rfc7636#section-4.5
+    code_verifier: str = Field(..., description="PKCE code verifier")
+    # RFC 8707 resource indicator
+    resource: str | None = Field(None, description="Resource indicator for the token")
+
+
+class RefreshTokenRequest(BaseModel):
+    # See https://datatracker.ietf.org/doc/html/rfc6749#section-6
+    grant_type: Literal["refresh_token"]
+    refresh_token: str = Field(..., description="The refresh token")
+    scope: str | None = Field(None, description="Optional scope parameter")
+    client_id: str
+    # we use the client_secret param, per https://datatracker.ietf.org/doc/html/rfc6749#section-2.3.1
+    client_secret: str | None = None
+    # RFC 8707 resource indicator
+    resource: str | None = Field(None, description="Resource indicator for the token")
+
+
+class TokenRequest(
+    RootModel[
+        Annotated[
+            AuthorizationCodeRequest | RefreshTokenRequest,
+            Field(discriminator="grant_type"),
+        ]
+    ]
+):
+    root: Annotated[
+        AuthorizationCodeRequest | RefreshTokenRequest,
+        Field(discriminator="grant_type"),
+    ]
+
+
+class TokenErrorResponse(BaseModel):
+    """
+    See https://datatracker.ietf.org/doc/html/rfc6749#section-5.2
+    """
+
+    error: TokenErrorCode
+    error_description: str | None = None
+    error_uri: AnyHttpUrl | None = None
+
+
+class TokenSuccessResponse(RootModel[OAuthToken]):
+    # this is just a wrapper over OAuthToken; the only reason we do this
+    # is to have some separation between the HTTP response type, and the
+    # type returned by the provider
+    root: OAuthToken
+
+
+@dataclass
+class TokenHandler:
+    provider: OAuthAuthorizationServerProvider[Any, Any, Any]
+    client_authenticator: ClientAuthenticator
+
+    def response(self, obj: TokenSuccessResponse | TokenErrorResponse):
+        status_code = 200
+        if isinstance(obj, TokenErrorResponse):
+            status_code = 400
+
+        return PydanticJSONResponse(
+            content=obj,
+            status_code=status_code,
+            headers={
+                "Cache-Control": "no-store",
+                "Pragma": "no-cache",
+            },
+        )
+
+    async def handle(self, request: Request):
+        try:
+            client_info = await self.client_authenticator.authenticate_request(request)
+        except AuthenticationError as e:
+            # Authentication failures should return 401
+            return PydanticJSONResponse(
+                content=TokenErrorResponse(
+                    error="unauthorized_client",
+                    error_description=e.message,
+                ),
+                status_code=401,
+                headers={
+                    "Cache-Control": "no-store",
+                    "Pragma": "no-cache",
+                },
+            )
+
+        try:
+            form_data = await request.form()
+            token_request = TokenRequest.model_validate(dict(form_data)).root
+        except ValidationError as validation_error:  # pragma: no cover
+            return self.response(
+                TokenErrorResponse(
+                    error="invalid_request",
+                    error_description=stringify_pydantic_error(validation_error),
+                )
+            )
+
+        if token_request.grant_type not in client_info.grant_types:  # pragma: no cover
+            return self.response(
+                TokenErrorResponse(
+                    error="unsupported_grant_type",
+                    error_description=(f"Unsupported grant type (supported grant types are {client_info.grant_types})"),
+                )
+            )
+
+        tokens: OAuthToken
+
+        match token_request:
+            case AuthorizationCodeRequest():
+                auth_code = await self.provider.load_authorization_code(client_info, token_request.code)
+                if auth_code is None or auth_code.client_id != token_request.client_id:
+                    # if code belongs to different client, pretend it doesn't exist
+                    return self.response(
+                        TokenErrorResponse(
+                            error="invalid_grant",
+                            error_description="authorization code does not exist",
+                        )
+                    )
+
+                # make auth codes expire after a deadline
+                # see https://datatracker.ietf.org/doc/html/rfc6749#section-10.5
+                if auth_code.expires_at < time.time():
+                    return self.response(
+                        TokenErrorResponse(
+                            error="invalid_grant",
+                            error_description="authorization code has expired",
+                        )
+                    )
+
+                # verify redirect_uri doesn't change between /authorize and /tokens
+                # see https://datatracker.ietf.org/doc/html/rfc6749#section-10.6
+                if auth_code.redirect_uri_provided_explicitly:
+                    authorize_request_redirect_uri = auth_code.redirect_uri
+                else:  # pragma: no cover
+                    authorize_request_redirect_uri = None
+
+                # Convert both sides to strings for comparison to handle AnyUrl vs string issues
+                token_redirect_str = str(token_request.redirect_uri) if token_request.redirect_uri is not None else None
+                auth_redirect_str = (
+                    str(authorize_request_redirect_uri) if authorize_request_redirect_uri is not None else None
+                )
+
+                if token_redirect_str != auth_redirect_str:
+                    return self.response(
+                        TokenErrorResponse(
+                            error="invalid_request",
+                            error_description=("redirect_uri did not match the one used when creating auth code"),
+                        )
+                    )
+
+                # Verify PKCE code verifier
+                sha256 = hashlib.sha256(token_request.code_verifier.encode()).digest()
+                hashed_code_verifier = base64.urlsafe_b64encode(sha256).decode().rstrip("=")
+
+                if hashed_code_verifier != auth_code.code_challenge:
+                    # see https://datatracker.ietf.org/doc/html/rfc7636#section-4.6
+                    return self.response(
+                        TokenErrorResponse(
+                            error="invalid_grant",
+                            error_description="incorrect code_verifier",
+                        )
+                    )
+
+                try:
+                    # Exchange authorization code for tokens
+                    tokens = await self.provider.exchange_authorization_code(client_info, auth_code)
+                except TokenError as e:
+                    return self.response(
+                        TokenErrorResponse(
+                            error=e.error,
+                            error_description=e.error_description,
+                        )
+                    )
+
+            case RefreshTokenRequest():  # pragma: no cover
+                refresh_token = await self.provider.load_refresh_token(client_info, token_request.refresh_token)
+                if refresh_token is None or refresh_token.client_id != token_request.client_id:
+                    # if token belongs to different client, pretend it doesn't exist
+                    return self.response(
+                        TokenErrorResponse(
+                            error="invalid_grant",
+                            error_description="refresh token does not exist",
+                        )
+                    )
+
+                if refresh_token.expires_at and refresh_token.expires_at < time.time():
+                    # if the refresh token has expired, pretend it doesn't exist
+                    return self.response(
+                        TokenErrorResponse(
+                            error="invalid_grant",
+                            error_description="refresh token has expired",
+                        )
+                    )
+
+                # Parse scopes if provided
+                scopes = token_request.scope.split(" ") if token_request.scope else refresh_token.scopes
+
+                for scope in scopes:
+                    if scope not in refresh_token.scopes:
+                        return self.response(
+                            TokenErrorResponse(
+                                error="invalid_scope",
+                                error_description=(f"cannot request scope `{scope}` not provided by refresh token"),
+                            )
+                        )
+
+                try:
+                    # Exchange refresh token for new tokens
+                    tokens = await self.provider.exchange_refresh_token(client_info, refresh_token, scopes)
+                except TokenError as e:
+                    return self.response(
+                        TokenErrorResponse(
+                            error=e.error,
+                            error_description=e.error_description,
+                        )
+                    )
+
+        return self.response(TokenSuccessResponse(root=tokens))