fix: tool-result message for non-vision tools (KeyError on width); polza provider verified end-to-end (vision + mission on first attempt)

testbed/README.md

@@ -64,6 +64,25 @@ taken); stop the old one with `fuser -k 8765/tcp` or Ctrl-C in its terminal.
 The demo prints a full transcript of tool calls/results to stdout and saves the
 capsule's final first-person frame to `demo_final_frame.png`.
 
+## Providers
+
+Provider presets resolve endpoint + API key + default model:
+
+```bash
+export POLZA_API_KEY="..."        # from https://polza.ai/dashboard/api-keys
+scripts/run_chat.sh --provider polza            # openai/gpt-5.6-luna, vision ON
+scripts/run_demo.sh --provider polza --agent llm
+scripts/run_demo.sh --provider openai --model gpt-4o-mini
+# local ollama stays the default (no flags needed)
+
+# anything else OpenAI-compatible:
+scripts/run_chat.sh --base-url https://... --model ... --api-key ...
+```
+
+Keys are read from the environment (`POLZA_API_KEY`, `OPENAI_API_KEY`), never
+stored in the repo. Multimodal models (gpt-5.x, gemma, qwen-vl, ...) get real
+camera frames automatically; `--vision`/`--no-vision` override.
+
 ## Interactive chat mode
 
 Talk to the capsule's brain in natural language (any language):