parity-testing

parity-testing is a skill for Claude Code, Codex from NVIDIA-NeMo/Megatron-Bridge. It costs 69 tokens per session (2,339 once invoked), scanned A, original, Apache-2.0.

A testing guide for checking that model weights and outputs match between Hugging Face and Megatron Core, two machine-learning model systems.

In plain words
What is it for?
It helps run single- or multi-GPU weight round-trip tests, compare model logits, verify weights in Python, and perform text or vision-language generation checks.
Why use it?
It helps identify whether a model conversion changed weights or predictions, and separates exact weight checks from output and text-generation checks.

Skill for Claude CodeCodex

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

Good fit It helps run single- or multi-GPU weight round-trip tests, compare model logits, verify weights in Python, and perform text or vision-language generation checks.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/nvidia-nemo/megatron-bridge/parity-testing
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 NVIDIA-NeMo/Megatron-Bridge --skill parity-testing
Clone the repo
git clone --depth 1 https://github.com/NVIDIA-NeMo/Megatron-Bridge

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 parity-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/nvidia-nemo/megatron-bridge/parity-testing/github.svg)](https://agentmods.dev/skills/nvidia-nemo/megatron-bridge/parity-testing)
Your own site
<a href="https://agentmods.dev/skills/nvidia-nemo/megatron-bridge/parity-testing"><img src="https://agentmods.dev/badge/skills/nvidia-nemo/megatron-bridge/parity-testing/github.svg" alt="Measured on agentmods" height="20"></a>

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 parity-testing

Your own site · 80×15
<a href="https://agentmods.dev/skills/nvidia-nemo/megatron-bridge/parity-testing"><img src="https://agentmods.dev/badge/skills/nvidia-nemo/megatron-bridge/parity-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,339 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 $0.00069 $0.02339
Opus 5.5 $0.00028 $0.00936
Sonnet 5.5 $0.00014 $0.00468
Haiku 4.5 $0.00007 $0.00234

Measured 11d ago against content hash bc3fcd684572, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

parity-testing 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 11d 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.

skills/parity-testing/SKILL.md · 217 lines

How it starts

The opening of the file, as written. The whole thing — 217 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Parity Testing for Megatron Bridge

This skill provides the decision framework for choosing the right verification tool and interpreting results. For the full model onboarding workflow (which includes parity testing as milestones 1 and 2), see the add-model-support skill.

Quick Decision: Which Tool to Run

What you want to verify Tool GPU? When to use
All weights round-trip exactly (single GPU) hf_megatron_roundtrip.py No First check after writing a bridge
Weights round-trip with TP/PP/EP hf_megatron_roundtrip_multi_gpu.py Yes After single-GPU passes
Forward-pass logit correlation compare_hf_and_megatron/compare.py Yes After round-trip passes
Text generation sanity hf_to_megatron_generate_text.py Yes Separate inference evidence
Programmatic weight check weights_verification_table() Yes Inside Python scripts
VLM generation sanity hf_to_megatron_generate_vlm.py Yes VLM models

All tools live under examples/conversion/.

3-Level Test Strategy

Level 1: State Dict Round-Trip (exact match)

Check tensor coverage and mapping behavior before interpreting forward results. Pure layout transformations must round-trip weights exactly. Investigate arithmetic parameter transformations separately from missing or misplaced weights.

# Single-GPU round-trip
uv run python examples/conversion/hf_megatron_roundtrip.py \
    --hf-model-id <org>/<model>

# Multi-GPU with TP=2
uv run python -m torch.distributed.run --nproc_per_node=2 \
    examples/conversion/hf_megatron_roundtrip_multi_gpu.py \
    --hf-model-id <org>/<model> --tp 2

# Multi-GPU with PP=2
uv run python -m torch.distributed.run --nproc_per_node=2 \
    examples/conversion/hf_megatron_roundtrip_multi_gpu.py \
    --hf-model-id <org>/<model> --pp 2

Expected: Every weight mapped by pure layout transformations shows "Matches Original: checkmark". Investigate every "X" before assigning a cause.

Read the full file on GitHub · 217 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. 11d ago Changed · +1 lines bc3fcd684572
  2. 25d ago Changed · +15 lines e7a3d1b3ae7b
  3. 1mo ago Changed · +9 lines 858d41e321d4
  4. 1mo ago First seen · 192 lines · 69 tokens per session scan A 7ed8b6298d81

Subscribe to this mod's changes

parity-testing is a skill published in the GitHub repository NVIDIA-NeMo/Megatron-Bridge (970 stars, last pushed today), licensed Apache-2.0. It adds 69 tokens to every session and 2,339 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 2026-08-30.

Related

Other skills, from other repositories

cli-eval

Create and run evaluation suites, watch live benchmark progress, view scorecards, compare model performance, and integrate eval runs with CI workflows from the CLI.

diegosouzapw/OmniRoute · 34 tokens

model-merging

Merge multiple fine-tuned models using mergekit to combine capabilities without retraining. Use when creating specialized models by blending domain-specific expertise (math + coding + chat), improving performance beyond single models, or experimenting rapidly with model variants. Covers SLERP, TIES-Merging, DARE, Task…

davila7/claude-code-templates · 73 tokens

darwinian-evolver

Evolve prompts/regex/SQL/code with Imbue's evolution loop.

NousResearch/hermes-agent · 22 tokens

dummy-dataset

Generate realistic dummy datasets for testing with customizable columns, constraints, and output formats (CSV, JSON, SQL, Python script). Use when creating test data, building mock datasets, or generating sample data for development and demos.

phuryn/pm-skills · 48 tokens

validate

Validate Semantica pipelines, extraction quality, graph schemas, and ontology consistency. Returns structured error/warning checklists. Uses PipelineValidator, PipelineBuilder.validatepipeline(), GraphValidator, and OntologyValidator. Sub-commands: pipeline, step, dependencies, extraction, graph, ontology, performance.

semantica-agi/semantica · 0 tokens

launching-evals

Run, monitor, analyze, and debug LLM evaluations via nemo-evaluator-launcher. Covers running evaluations, checking status and live progress, debugging failed runs, exporting artifacts and logs, and analyzing results. ALWAYS triggers on mentions of running evaluations, checking progress, debugging failed evals…

NVIDIA/Model-Optimizer · 115 tokens