---
license: mit
language:
  - en
task_categories:
  - text-generation
tags:
  - function-calling
  - tool-use
  - router
  - synthetic
  - macos
  - gemma
size_categories:
  - 1K<n<10K
configs:
  - config_name: v1-baked
    default: true
    data_files:
      - split: train
        path: v1-baked/train.jsonl
      - split: validation
        path: v1-baked/valid.jsonl
  - config_name: v1-incontext
    data_files:
      - split: train
        path: v1/train.jsonl
      - split: validation
        path: v1/valid.jsonl
---

# yo-router-data

Synthetic training data for **`yo`**, a macOS tool router fine-tuned from FunctionGemma-270M.
Each row maps one plain-English utterance to exactly one function call over a fixed menu of 10
read-only macOS tools.

This is the dataset that produced [`lagna360/yo-router-270m`](https://huggingface.co/lagna360/yo-router-270m)
(56.2% → 95.2% tool accuracy). Generator, eval harness and full results:
[github.com/lagna360/yo](https://github.com/lagna360/yo).

**It is fully reproducible.** Everything here is regenerable byte-for-byte from
`data/generate.py` at seed 17 — the dataset is published for convenience, not because it is
irrecoverable.

## Configurations

Nine variants exist, all from one generator. The main two:

| config | rows | prompt tokens | what it is |
|---|---|---|---|
| **`v1-baked`** | 3,000 | 32 | tool declarations **omitted** from the prompt — the shipping config |
| `v1` | 3,000 | 654 | the same 3,000 rows with all 10 declarations in the prompt |

Plus scaling and ablation variants used to produce the study's tables:

| config | rows | baked | note |
|---|---|---|---|
| `v1-baked-500` | 500 | yes | dataset-size sweep |
| `v1-baked-1000` | 1,000 | yes | dataset-size sweep |
| `v1-baked-10000` | 10,000 | yes | dataset-size sweep |
| `v1-1k` | 1,000 | no | dataset-size sweep, in-context |
| `v1-10k` | 10,000 | no | dataset-size sweep, in-context |
| `v1-nocontrast` | 3,000 | no | **ablation:** contrastive pairs removed |
| `v1-noargs` | 3,000 | no | **ablation:** all arguments stripped |

Each config directory carries a `config.json` recording `n`, `seed`, per-tool counts,
`with_args`, and measured prompt length.

## Format

MLX-LM completion format — two string fields, and the loss is taken on `completion` only
(`mask_prompt: true`).

```json
{
  "prompt": "<bos><start_of_turn>developer\nYou are a model that can do function calling with the following functions<end_of_turn>\n<start_of_turn>user\nlook for meeting notes please<end_of_turn>\n<start_of_turn>model\n",
  "completion": "<start_function_call>call:find_files{name:<escape>meeting notes<escape>}<end_function_call>"
}
```

In the `v1` (in-context) configs the prompt additionally carries a
`<start_function_declaration>…<end_function_declaration>` block for all 10 tools, which is what
takes it from 32 to 654 tokens.

Call format: `call:<tool>{key:<escape>value<escape>,…}` with keys sorted, or `call:<tool>{}` when
there are no arguments.

A sidecar `meta.jsonl` carries the structured ground truth for each row, for analysis:

```json
{"tool": "find_files", "utterance": "which folder has screenshot please", "args": {"name": "screenshot"}}
```

Files per config: `train.jsonl`, `valid.jsonl` (8% split), `meta.jsonl`, `config.json`.

## The 10 tools

`disk_usage`(path) · `storage_summary` · `largest_files`(path) · `find_files`(name, path) ·
`top_processes`(sort_by) · `network_listeners`(port) · `network_info` · `battery_status` ·
`system_info` · `datetime`

## How it was generated

Fully deterministic — `random.Random(17)`, no model in the loop, no LLM-generated text.

1. **200 hand-written stems**, 20 per tool, each a phrasing of that tool's intent, with
   `{path}` / `{name}` / `{port}` / `{sort}` placeholders where arguments belong.
2. **Slot pools** substituted into the placeholders: 19 paths, 20 filenames, 15 ports, 5 sort
   keys. Natural-language slot values are canonicalised to real argument values
   (`"the downloads folder"` → `~/Downloads`, `"ram"` → `mem`).
3. **Surface noise:** a prefix from `{"", "yo ", "hey ", "can you ", "pls ", "tell me ", …}` — but
   suppressed 75% of the time when the utterance already opens with a question word, so
   `"can you what time is it"` never appears — and a suffix from `{"", "?", " please",
   " thanks", …}`. Then, per row: 12% get a realistic single-keystroke slip (drop / transpose /
   double), 6% are shouted in ALL CAPS, and 12% get a leading capital.
4. **27 contrastive stems**, oversampled 3x. Near-identical phrasings that differ only in the
   discriminating word, with each confusable tool represented — e.g. `"space left"` →
   `storage_summary`, `"space used by folder"` → `disk_usage`, `"space used by file"` →
   `largest_files`. These target the boundaries the confusion matrix showed as weak
   (`storage_summary` vs `disk_usage`, `disk_usage` vs `largest_files`, `network_listeners` vs
   `top_processes`).
5. **Argument boost** (`--arg-boost 3`) weights slot-bearing stems 3x, because argument extraction
   converges far more slowly than tool selection.
6. **Render** into the FunctionGemma chat template, with declarations (`v1`) or without
   (`v1-baked`).
7. **Split** 92% train / 8% validation.

For `v1-baked` this yields 3,000 rows, **1,840 of them (61%) carrying at least one argument**,
distributed across tools as: `find_files` 637, `disk_usage` 490, `largest_files` 440,
`network_listeners` 434, `top_processes` 254, `storage_summary` 196, `network_info` 158,
`battery_status` 143, `system_info` 138, `datetime` 110. The distribution is deliberately
uneven — tools with arguments get more rows because they have more to learn.

Regenerate any config with:

```bash
python data/generate.py --n 3000 --out data/out/v1-baked --baked
```

## Leakage: asserted, not assumed

The 249-case evaluation set (`eval/testset.jsonl` in the repo) was **hand-written before any
training**, by a person, and never by this generator. To keep those two worlds apart the generator
**hard-fails at generation time** if any training utterance exactly matches a test utterance:

```python
leaked = [r for r in rows if r["utterance"].strip().lower() in test_u]
if leaked:
    raise SystemExit(f"LEAK: {len(leaked)} training utterances match the test set: ...")
```

This is not decorative — **it caught a real collision**. The stem `"why is {path} so big"` with
`path="my home folder"` generated a verbatim copy of a test case. The stem was changed. See
`LAB_NOTES.md` in the repo.

Caveat, stated plainly: the guard checks **exact normalised string equality**, not semantic
similarity. Near-duplicates ("what time is it" / "whats the time") can and do exist across the two
sets. That is intentional — the test set is meant to measure in-domain generalisation, not
zero-shot transfer — but it means the headline accuracy should be read as "accuracy on paraphrases
of the trained intents", not "accuracy on unseen intents".

## Known weaknesses

- **Slot-value pools are small and fixed** (19 paths, 20 names, 15 ports). Scaling the row count
  therefore recycles the same argument values. This is measurable: going from 3k to 10k rows
  raised tool accuracy 95.2% → 95.6% while *dropping* argument accuracy 82.3% → 77.4%. **If you
  scale this dataset, scale the slot pools with it.**
- **Synthetic phrasing.** Hand-written stems plus programmatic noise. Real user language has a
  much longer tail.
- **No negative class.** Every row is a tool call. There is no `chitchat` / no-tool example, which
  is exactly why the resulting model forces a tool onto "hi".
- **English, macOS, single-call only.** No chaining, no multi-tool rows, no other language.
- **Not human-reviewed row by row.** The stems were written by hand; the 3,000 expansions were not
  individually inspected.

## Licence

**MIT.** Copyright (c) 2026 Pankaj Upreti.

The rows are programmatic expansions of hand-written English stems — no model generated them, no
scraped corpus is involved, and no personal data is present. The paths and filenames in the slot
pools are generic placeholders (`~/Downloads`, `invoice`, `screenshot`), not real user data.

**Provenance of the `prompt` field.** The utterances, the tool labels and the argument values are
original work and are MIT. The `prompt` field, however, is those utterances rendered through
FunctionGemma's chat template — so it carries that model's control tokens and declaration syntax
(`<start_function_declaration>`, `<escape>`, and so on). No Gemma model generated any text here;
`data/generate.py` loads the tokenizer only to apply its template. We take the view that a prompt
format is an interchange schema rather than model output, and licence the data MIT accordingly —
but the provenance is stated plainly so you can form your own view. The `tool` and `args` fields in
`meta.jsonl` are format-independent if you would rather re-render the prompts for another model.

**One caveat about downstream use.** This data is MIT, but the *model* trained on it in this
project is a FunctionGemma derivative and is governed by the
[Gemma Terms of Use](https://ai.google.dev/gemma/terms) — the dataset licence does not and cannot
loosen that. Training an unrelated, non-Gemma model on this data carries no such obligation.

## Citation

```bibtex
@misc{upreti2026yodata,
  author = {Upreti, Pankaj},
  title  = {yo-router-data: synthetic tool-routing data for macOS system queries},
  year   = {2026},
  url    = {https://github.com/lagna360/yo}
}
```