synthetic-data-generation

synthetic-data-generation is a skill for Claude Code, Codex from jnPiyush/AgentX. It costs 68 tokens per session (1,118 once invoked), scanned A, original, Apache-2.0.

A guide to creating made-up but useful datasets for training, testing, evaluation, and search systems.

In plain words
What is it for?
Use it to bootstrap evaluation sets, expand fine-tuning data, create adversarial cases, augment a RAG document collection, or prepare privacy-safe development data.
Why use it?
It provides substitutes when real data is private, scarce, or missing rare cases. It also covers filtering, removing duplicates, checking contamination, and recording where generated data came from.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to bootstrap evaluation sets, expand fine-tuning data, create adversarial cases, augment a RAG document collection, or prepare privacy-safe development data.

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Install with agentmods
npx agentmods add skills/jnpiyush/agentx/synthetic-data-generation
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add jnPiyush/AgentX --skill synthetic-data-generation
Clone the repo
git clone --depth 1 https://github.com/jnPiyush/AgentX

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for synthetic-data-generation

README.md
[![agentmods](https://agentmods.dev/badge/skills/jnpiyush/agentx/synthetic-data-generation/github.svg)](https://agentmods.dev/skills/jnpiyush/agentx/synthetic-data-generation)
Your own site
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Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for synthetic-data-generation

Your own site · 80×15
<a href="https://agentmods.dev/skills/jnpiyush/agentx/synthetic-data-generation"><img src="https://agentmods.dev/badge/skills/jnpiyush/agentx/synthetic-data-generation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,118 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00068 $0.01118
Opus 5.5 $0.00027 $0.00447
Sonnet 5.5 $0.00014 $0.00224
Haiku 4.5 $0.00007 $0.00112

Measured 1mo ago against content hash 5d14c8a303fe, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

synthetic-data-generation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.github/skills/ai-systems/synthetic-data-generation/SKILL.md · 140 lines

How it starts

The opening of the file, as written. The whole thing — 140 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Synthetic Data Generation

Purpose: Build training and eval datasets quickly without violating user privacy, while controlling for quality, diversity, and contamination.


When to Use This Skill

  • Bootstrapping eval sets when you have no real labeled data
  • Augmenting fine-tuning data for under-represented intents / slices
  • Generating adversarial test cases (combine with ai-safety-and-red-teaming)
  • Creating QA pairs over a private RAG corpus
  • Privacy-safe substitutes for production data in dev/test

When NOT to Use

  • If real, well-labeled data exists at sufficient scale -- use it
  • For final benchmark numbers in regulated decisions -- use human-labeled holdouts

Common Techniques

Technique Use For
Self-Instruct Generate instruction/response pairs from a small seed
Evol-Instruct Iteratively rewrite prompts to be deeper, broader, harder
Persona-based Generate from N personas to enforce demographic / role diversity
Distillation Strong-model answers used to train smaller model (check provider terms)
Back-translation Multilingual coverage
Counterfactual augmentation Flip protected attributes to test fairness
Programmatic / templated Slot-fill structured data with controlled noise
RAG-grounded QA Generate Q & A from each chunk; ideal for eval sets

Pipeline

1. Define target distribution and slices (intents, difficulty, demographics)
2. Choose generator model (often a strong reasoning model)
3. Seed with examples or schema
4. Generate at over-sample rate (2-5x target)
5. Quality filter: schema validation, toxicity, dedupe
6. Diversity filter: embedding clustering, slice balancing
7. Decontamination: remove overlap with eval/test sets
8. Human review on a sample (5-10%)
9. Dataset card + version + provenance

Quality Filters

Filter Tool
Schema valid JSON Schema, Pydantic
Length sane Token count bounds
Language correct fastText / lid.176
Toxicity / unsafe LlamaGuard, Azure Content Safety
PII present Presidio
Dedupe (near) MinHash / SimHash, embedding cosine
Factuality (RAG) Citation present and supports claim
Difficulty balanced LLM judge classifies easy/medium/hard

Read the full file on GitHub · 140 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago Changed 5d14c8a303fe
  2. 1mo ago First seen · 140 lines · 68 tokens per session scan A f138a3fdc7ea

Subscribe to this mod's changes

synthetic-data-generation is a skill published in the GitHub repository jnPiyush/AgentX (16 stars, last pushed 3d ago), licensed Apache-2.0. It adds 68 tokens to every session and 1,118 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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