Local OpenAI-compatible agent fails with community access error

### Summary

I am trying to use Buzz agents with a local OpenAI-compatible `llama.cpp` server. The local API works correctly when tested directly, but Buzz fails before sending the request to the LLM with:

```text
Community access denied this agent — check its community membership.
```

This happens even though the agent is visible in the community and can send the initial welcome message.

### Environment

- Buzz version: 0.5.3
- OS: macOS 15.7.5 intel
- Agent(s) tested: Bumble and Fizz
- Local model: `qwen40.gguf`
- Backend: `llama.cpp`
- Local API: `http://127.0.0.1:8082/v1`

### Local model configuration

The Buzz UI does not provide a field for a custom OpenAI-compatible base URL. The provider settings only expose the provider/model configuration, so I configured the local endpoint through environment variables in Terminal.

I first quit Buzz and then ran:

```bash
export BUZZ_AGENT_PROVIDER=openai
export OPENAI_COMPAT_BASE_URL=http://127.0.0.1:8082/v1
export OPENAI_COMPAT_MODEL=qwen40.gguf
export OPENAI_COMPAT_API_KEY=ollama
export OPENAI_COMPAT_API=chat
```

The variables were verified with:

```bash
env | grep -E 'BUZZ_AGENT|OPENAI_COMPAT'
```

Buzz Desktop was then started from the same environment:

```bash
/Applications/Buzz.app/Contents/MacOS/buzz-desktop
```

The relevant Buzz settings were:

```text
Provider: OpenAI-compatible
Model: qwen40.gguf
Thinking / Effort: none

Provider initially tested: OpenAI-compatible
BUZZ_AGENT_PROVIDER initially used: openai
BUZZ_AGENT_PROVIDER later tested: openai-compat

```

The local server was configured with a 16k context window because the default 4096 context was too small for Buzz agent prompts.

### Verification that the local API works

The local endpoint responds correctly to the OpenAI-compatible chat endpoint:

```bash
curl http://127.0.0.1:8082/v1/chat/completions \
-H "Content-Type: application/json" \
-d '{
"model": "qwen40.gguf",
"messages": [
{
"role": "user",
"content": "Odpověz pouze: funguje" (Answer only: It works)
}
],
"temperature": 0
}'
```

The response was a valid OpenAI-compatible `chat.completion` response and contained:

```text
funguje (it works)
```

### Previous version / earlier problems

Before upgrading from Buzz 0.5.2 to 0.5.3, the local model was reached successfully by Buzz. However, there were several problems:

1. With llama.cpp's default context size of 4096, Buzz generated requests larger than the available context:

```text
request (7566 tokens) exceeds the available context size (4096 tokens)
```

and later requests were between approximately 8k and 14k tokens.

2. After increasing llama.cpp's context to 16384, Buzz successfully sent requests and llama.cpp generated responses. The logs showed prompt processing and decoded tokens, for example:

```text
n_decoded = 100
tg = 2.6 t/s
```

3. Despite the model generating output, the response was sometimes not displayed in the channel or thread. It appeared that the agent was thinking or responding in the activity log, but no visible reply was published. (issue #2421 )

4. The repository changelog for 0.5.3 contains:

```text
feat(agent): optional reply guard reminds a silent turn to publish (#3763)
```

which appears potentially related to the previous silent-reply behavior.

After upgrading to 0.5.3, I can no longer reliably reach the LLM because the request now fails earlier with the community-access error described below.

### Current reproducible behavior

1. Create or open an agent in Buzz.
2. The agent is visible in the community.
3. The agent can send its initial welcome message.
4. Reply to the agent in a direct message or thread.
5. The UI briefly shows `Thinking`.
6. The turn fails with:

```text
Community access denied this agent — check its community membership.
```

The same behavior occurs in two different communities. It is not limited to one community.

The error also occurs with both Bumble and Fizz.

No request is generated in the local llama.cpp log when this error occurs. This indicates that the failure happens before the agent calls the configured LLM endpoint.

### Expected behavior

If the agent is visible in the community and can send a welcome message, replying to it should pass the community-access check and invoke the configured LLM provider.

### Additional observations

- The error is not caused by the local model endpoint; the endpoint works independently via `curl`.
- The error occurs before any LLM request is sent.
- The agent appears to have community membership because it is visible and can send the welcome message.
- The same error occurs in multiple communities.
- Direct messages and thread interactions were both tested.
- The local OpenAI-compatible provider configuration was established through environment variables because the desktop UI does not expose a custom base URL field.
```

### Additional error observed later

After further testing, another error appeared in agent messages:

```text
⚠️ I couldn't process the last request after multiple retries
(Agent reported error (code -32001): llm auth:
{
"error": {
"message": "Incorrect API key provided: local. You can find your API key at https://platform.openai.com/account/api-keys.",
"type": "invalid_request_error",
"param": null,
"code": "invalid_api_key"
}
})

This indicates that, in this case, Buzz sent the dummy local API key (local) to the real OpenAI API instead of using the configured OpenAI-compatible endpoint.

The local provider was configured through:

Bash

export BUZZ_AGENT_PROVIDER=openai
export OPENAI_COMPAT_BASE_URL=http://127.0.0.1:8082/v1
export OPENAI_COMPAT_MODEL=qwen40.gguf
export OPENAI_COMPAT_API_KEY=ollama
export OPENAI_COMPAT_API=chat

The Buzz Desktop application was then launched from the same environment:

Bash

/Applications/Buzz.app/Contents/MacOS/buzz-desktop

After changing:

Bash

export BUZZ_AGENT_PROVIDER=openai

to:

Bash

export BUZZ_AGENT_PROVIDER=openai-compat

the OpenAI API-key error has not appeared again so far, although this is not yet conclusive because the error only appeared after multiple retries and with a delay.

The following error still occurs:

text

Community access denied this agent — check its community membership.

This suggests there may be two separate issues:

In some situations, the openai provider ignores the OPENAI_COMPAT_* configuration and sends the dummy key to the real OpenAI API.
Even with openai-compat, the agent may fail the community-access check before a request reaches the configured LLM endpoint.

No request appears in the local llama.cpp server log when the community-access error occurs.

Start by reproducing a direct-message and thread turn with BUZZ_AGENT_PROVIDER set to openai-compat, then compare handling of the OPENAI_COMPAT_* variables with the openai provider. Check the community-access decision before the /v1/chat/completions request and confirm whether the local llama.cpp log remains empty. Done means authorized community interactions reach the configured endpoint without using the real OpenAI API or rejecting valid membership.

Written by the indexing model from the issue text.