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
(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.
- 200 hand-written stems, 20 per tool, each a phrasing of that tool's intent, with
{path}/{name}/{port}/{sort}placeholders where arguments belong. - 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). - 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. - 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_summaryvsdisk_usage,disk_usagevslargest_files,network_listenersvstop_processes). - Argument boost (
--arg-boost 3) weights slot-bearing stems 3x, because argument extraction converges far more slowly than tool selection. - Render into the FunctionGemma chat template, with declarations (
v1) or without (v1-baked). - 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}
}