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 (56.2% → 95.2% tool accuracy). Generator, eval harness and full results: 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).

{
  "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:

{"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:

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:

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 — the dataset licence does not and cannot loosen that. Training an unrelated, non-Gemma model on this data carries no such obligation.

Citation

@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}
}