Looker giving 500 error when using user Oauth

### Prerequisites

- [x] I've searched the current open issues
- [x] I've updated to the latest version of Toolbox

### Toolbox version

toolbox version 0.24.0+dev.linux.amd64

### Environment

1. OS type and version: (output of `uname -a`)
2. How are you running Toolbox: 
  - As a downloaded binary (e.g. from `curl -O https://storage.googleapis.com/genai-toolbox/v$VERSION/linux/amd64/toolbox`)
  - As a container (e.g. from `us-central1-docker.pkg.dev/database-toolbox/toolbox/toolbox:$VERSION`)
  - Compiled from source (include the command used to build)


### Client

1. Client: <name and link to the client are you using>
2. Version: <what exact version of the client are you using> 
3. Example: If possible, please include your code of configuration:

```python
# Code goes here! 
```


### Expected Behavior

I was following this doc to setup the mcp server with my gemini using client oauth. The doc I am following is: https://googleapis.github.io/genai-toolbox/samples/looker/looker_gemini_oauth/.

I was able to authenticate succefully. But when I ran a simple query like search dashboard with name "Surya" it failed. I was expected to pass.

### Current Behavior

It is throwing error in authentication whenever using user oauth. I have added error details in additional details. The mcp server is panicking because of nil pointer reference.

```
panic: runtime error: invalid memory address or nil pointer dereference
 
 -> github.com/looker-open-source/sdk-codegen/go/rtl.(*AuthSession).Login
 ->   /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/looker-open-source/sdk-codegen/go@v0.25.21/rtl/auth.go:78

    github.com/looker-open-source/sdk-codegen/go/rtl.(*AuthSession).Do
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/looker-open-source/sdk-codegen/go@v0.25.21/rtl/auth.go:136
```

### Steps to reproduce?

Just following this doc: https://googleapis.github.io/genai-toolbox/samples/looker/looker_gemini_oauth/


### Additional Details

Error logs:

service: "httplog" httpRequest: {url: "http://localhost:5000/mcp" method: "POST" path: "/mcp" remoteIP: "127.0.0.1:37686" proto: "HTTP/1.1" requestID: "suryaprakasha.c.googlers.com/cPSqNJl6HI-000001"} stacktrace: "#" panic: "runtime error: invalid memory address or nil pointer dereference" httpResponse: {status: 500 bytes: 0 elapsed: 1.097638} 
2025-12-23T10:07:26.851052802Z ERROR "Making request %v" {<nil> <nil> 0xc000c78600 <nil> <nil> <nil> <nil> <nil> <nil> <nil> <nil> <nil> <nil> <nil> <nil> 0xc001080518 0xc001080520 <nil> <nil> <nil>} 

 panic: runtime error: invalid memory address or nil pointer dereference
 
 -> github.com/looker-open-source/sdk-codegen/go/rtl.(*AuthSession).Login
 ->   /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/looker-open-source/sdk-codegen/go@v0.25.21/rtl/auth.go:78

    github.com/looker-open-source/sdk-codegen/go/rtl.(*AuthSession).Do
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/looker-open-source/sdk-codegen/go@v0.25.21/rtl/auth.go:136
    github.com/looker-open-source/sdk-codegen/go/sdk/v4.(*LookerSDK).SearchDashboards
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/looker-open-source/sdk-codegen/go@v0.25.21/sdk/v4/methods.go:3019
    github.com/googleapis/genai-toolbox/internal/tools/looker/lookergetdashboards.Tool.Invoke
      /usr/local/google/home/suryaprakasha/work/genai-toolbox/internal/tools/looker/lookergetdashboards/lookergetdashboards.go:154
    github.com/googleapis/genai-toolbox/internal/server/mcp/v20250618.toolsCallHandler
      /usr/local/google/home/suryaprakasha/work/genai-toolbox/internal/server/mcp/v20250618/method.go:180
    github.com/googleapis/genai-toolbox/internal/server/mcp/v20250618.ProcessMethod
      /usr/local/google/home/suryaprakasha/work/genai-toolbox/internal/server/mcp/v20250618/method.go:41
    github.com/googleapis/genai-toolbox/internal/server/mcp.ProcessMethod
      /usr/local/google/home/suryaprakasha/work/genai-toolbox/internal/server/mcp/mcp.go:106
    github.com/googleapis/genai-toolbox/internal/server.processMcpMessage
      /usr/local/google/home/suryaprakasha/work/genai-toolbox/internal/server/mcp.go:525
    github.com/googleapis/genai-toolbox/internal/server.httpHandler
      /usr/local/google/home/suryaprakasha/work/genai-toolbox/internal/server/mcp.go:412
    github.com/googleapis/genai-toolbox/internal/server.mcpRouter.func3
      /usr/local/google/home/suryaprakasha/work/genai-toolbox/internal/server/mcp.go:228
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/go-chi/chi/v5.(*Mux).routeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/mux.go:477
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/googleapis/genai-toolbox/internal/server.mcpRouter.SetContentType.func6.1
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/render@v1.0.3/content_type.go:52
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/go-chi/chi/v5/middleware.StripSlashes.func1
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/middleware/strip.go:31
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/go-chi/chi/v5/middleware.AllowContentType.func1.1
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/middleware/content_type.go:38
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/go-chi/chi/v5.(*Mux).ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/mux.go:73
    github.com/go-chi/chi/v5.(*Mux).Mount.func1
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/mux.go:321
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/go-chi/chi/v5.(*Mux).routeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/mux.go:477
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/go-chi/cors.(*Cors).Handler-fm.(*Cors).Handler.func1
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/cors@v1.2.2/cors.go:231
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/go-chi/chi/v5/middleware.Recoverer.func1
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/middleware/recoverer.go:45
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/googleapis/genai-toolbox/internal/server.NewServer.RequestLogger.Handler.func3.1
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/httplog/v2@v2.1.1/httplog.go:111
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/go-chi/chi/v5/middleware.RequestID.func1
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/middleware/request_id.go:76
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/go-chi/chi/v5.(*ChainHandler).ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/chain.go:31
    github.com/go-chi/chi/v5/middleware.Recoverer.func1
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/middleware/recoverer.go:45
    net/http.HandlerFunc.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2322
    github.com/go-chi/chi/v5.(*Mux).ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/github.com/go-chi/chi/v5@v5.2.3/mux.go:90
    net/http.serverHandler.ServeHTTP
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:3340
    net/http.(*conn).serve
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:2109
    created by net/http.(*Server).Serve in goroutine 97
      /usr/local/google/home/suryaprakasha/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.25.5.linux-amd64/src/net/http/server.go:3493
    
2025-12-23T10:07:26.851867744Z ERROR Response: 500 Server Error - runtime error: invalid memory address or nil pointer dereference service: "httplog" httpRequest: {url: "http://localhost:5000/mcp" method: "POST" path: "/mcp" remoteIP: "127.0.0.1:50016" proto: "HTTP/1.1" requestID: "suryaprakasha.c.googlers.com/cPSqNJl6HI-000002"} stacktrace: "#" panic: "runtime error: invalid memory address or nil pointer dereference" httpResponse: {status: 500 bytes: 0 elapsed: 0.924435} 


Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Looker giving 500 error when using user Oauth #2230

Prerequisites

Toolbox version

Environment

Client

Expected Behavior

Current Behavior

Steps to reproduce?

Additional Details

Metadata

Assignees

Labels

Type

Fields

Projects

Milestone

Relationships

Development

Looker giving 500 error when using user Oauth #2230

Description

Prerequisites

Toolbox version

Environment

Client

Expected Behavior

Current Behavior

Steps to reproduce?

Additional Details

Metadata

Metadata

Assignees

Labels

Type

Fields

Projects

Milestone

Relationships

Development

Issue actions