---
title: Pi Web Agent
sdk: static
app_file: dist/index.html
fullWidth: true
models:
  - onnx-community/Qwen2.5-Coder-0.5B-Instruct
  - onnx-community/Qwen3-0.6B-ONNX
  - Mike0021/MiniCPM5-1B-ONNX-Web
custom_headers:
  cross-origin-embedder-policy: credentialless
  cross-origin-opener-policy: same-origin
  cross-origin-resource-policy: cross-origin
---

# Pi Web Agent

This workspace ships a browser-only pi agent app backed by Transformers.js and WebContainers. The default planner is `onnx-community/Qwen2.5-Coder-0.5B-Instruct` because it produced the strongest browser result in the local task suite; Qwen3 0.6B and the converted MiniCPM5 model remain selectable for comparison.

Published artifact: https://huggingface.co/Mike0021/MiniCPM5-1B-ONNX-Web

The required runtime layout is:

- `config.json`, `generation_config.json`, tokenizer files, and `chat_template.jinja` at the repo root
- q4 ONNX weights at `onnx/model_q4.onnx`
- `config.json` includes `transformers.js_config.dtype = "q4"` so the default loader selects the web-sized artifact

The conversion uses an ONNX export with KV cache (`text-generation-with-past`) and then applies ONNX Runtime 4-bit MatMul quantization. A generic ONNX export without KV cache is not enough for normal Transformers.js autoregressive generation.

## Run the Web App

```bash
npm install
npm run dev
```

Open http://localhost:5173/.

The app uses:

- `@earendil-works/pi-agent-core` for the agent loop, transcript state, and tool execution.
- `@huggingface/transformers` with `onnx-community/Qwen2.5-Coder-0.5B-Instruct` as the default local browser planner.
- `@webcontainer/api` for the client-only sandbox with a virtual filesystem and browser-contained Node.js processes.

Vite serves the app with COOP/COEP headers and boots WebContainers with `coep: "credentialless"`. The deterministic test model is available at `http://localhost:5173/?mode=mock&device=wasm` for fast harness and sandbox smoke tests without downloading an ONNX model. The local model defaults to a tested 256-token generation budget in WASM mode and the UI allows budgets up to 8192.

The Static Space uses the same isolation policy through `custom_headers` in this README frontmatter. The app is built with `npm run build` and the generated `dist/` directory is uploaded to the Space.

## Test the Agent App

Start the dev server, then run:

```bash
npm run smoke:web
```

The smoke test opens Chromium, confirms `crossOriginIsolated`, submits the chat prompt in deterministic mode, boots the WebContainer sandbox, writes `hello.js`, spawns `node hello.js`, and checks for `pi sandbox result: 42` in the chat transcript.

For the heavier end-to-end check with the real ONNX model in browser WASM mode:

```bash
npm run smoke:local-model
```

This downloads/loads the q4 ONNX artifact in Chrome, runs the same pi/WebContainer task, and checks that the model reaches `Model ready` before the sandbox result is accepted.

The complex smoke test covers simple code execution, installing and using an npm package, and a multi-file ES module task:

```bash
npm run smoke:complex
```

The sandbox can install and use Node packages through the same `run_command` tool, for example `npm install is-number@7.0.0` followed by `node check-package.mjs`.

To probe larger browser generation budgets:

```bash
TOKEN_BUDGETS=80,256,2048,8192 npm run probe:tokens
```

Measured local WASM results with Qwen2.5-Coder 0.5B:

- `npm run smoke:local-model` passed at 80 max new tokens.
- `MAX_NEW_TOKENS=256 npm run smoke:complex` passed simple, npm dependency, and multi-file module tasks.
- `TOKEN_BUDGETS=80,160,256,512,1024,2048,4096,8192 npm run probe:tokens` passed. Higher caps were accepted; for the probe task the model stopped naturally before using the full cap.

## Verify the Published Artifact

```bash
npm install
node scripts/verify_tjs_model.mjs Mike0021/MiniCPM5-1B-ONNX-Web
```

The verifier asks Transformers.js for the `text-generation` file plan, checks for `onnx/model_q4.onnx`, then loads the model and generates a short completion.

## Convert and Upload

The published repo was produced locally with a CPU fp16 export followed by q4 ONNX quantization:

```bash
uv run --python 3.12 \
  --with "numpy<2" \
  --with "transformers==4.57.6" \
  --with "optimum[onnx]" \
  --with "onnxruntime==1.20.1" \
  --with onnxslim \
  --with "huggingface_hub>=0.33" \
  --with accelerate \
  --with sentencepiece \
  --with protobuf \
  scripts/convert_minicpm5_tjs.py \
  --source-model openbmb/MiniCPM5-1B \
  --target-repo Mike0021/MiniCPM5-1B-ONNX-Web \
  --output-dir output/MiniCPM5-1B-ONNX-Web \
  --work-dir output/minicpm5-work \
  --device cpu \
  --export-dtype fp16
```

For a clean remote conversion, the same script can be run on Hugging Face Jobs with a configured Hub token:

```bash
hf repos create Mike0021/MiniCPM5-1B-ONNX-Web --repo-type model --exist-ok
hf jobs uv run scripts/convert_minicpm5_tjs.py \
  --flavor l4x1 \
  --timeout 6h \
  --secrets HF_TOKEN \
  --with "numpy<2" \
  --with "transformers==4.57.6" \
  --with "optimum[onnx]" \
  --with "onnxruntime==1.20.1" \
  --with onnxslim \
  --with "huggingface_hub>=0.33" \
  --with accelerate \
  --with sentencepiece \
  --with protobuf \
  --python 3.12 \
  -- \
  --target-repo Mike0021/MiniCPM5-1B-ONNX-Web \
  --export-dtype fp16
```