vrm-expression-agent-harness: Instructions file for Codex

AGENTS.md

vrm-expression-agent-harness AGENTS.md is an instructions file for Codex, OpenCode from shinshin86/vrm-expression-agent-harness. It costs 447 tokens per session, scanned A, original, MIT.

A workflow guide for extending VRM avatar files with model-specific facial expressions. VRM is a file format for 3D humanoid avatars, and the guide explains how to inspect and safely transform those files.

In plain words
What is it for?
Use it when creating expression extensions for VRM, VRMA, or GLB avatar models and when preparing the resulting files for WebUI preview.
Why use it?
It prevents agents from overwriting source files, inventing unsupported expressions, exposing private model files, or skipping required checks and reports.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: mentions AGENTS.md.

This is shinshin86/vrm-expression-agent-harness's own configuration. It tells Codex and OpenCode how to work on vrm-expression-agent-harness itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything vrm-expression-agent-harness configures →

Reuse

Borrowing it

Nothing to install: this file belongs to shinshin86/vrm-expression-agent-harness. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/shinshin86/vrm-expression-agent-harness/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/shinshin86/vrm-expression-agent-harness

Made for: Codex, OpenCode.

Wrote this? Show the measurements

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README.md
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<a href="https://agentmods.dev/instructions/shinshin86/vrm-expression-agent-harness/agents-md"><img src="https://agentmods.dev/badge/instructions/shinshin86/vrm-expression-agent-harness/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 447 This file is loaded in full into every session.
When invoked 447 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.00447 $0.00447
Opus 5 $0.00224 $0.00224
Sonnet 5 $0.00089 $0.00089
Haiku 4.5 $0.00045 $0.00045

Measured 6d ago against content hash fe7eea435f69, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

vrm-expression-agent-harness AGENTS.md 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 6d 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.

AGENTS.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

You are an AI coding agent working in the VRM Expression Agent Harness.

Mission

Given a user-owned VRM file, produce the best model-specific AITuber expression extension that the file can honestly support. Follow the model-specific workflow: inspect, reason, derive from existing morph deltas, verify, self-review, and prepare for WebUI preview.

Non-Negotiable Rules

  • Read this file, docs/agent-operating-manual.md, and docs/success-contract.md before touching the target VRM.
  • Never overwrite the input VRM.
  • Never assume a universal conversion algorithm is sufficient.
  • Do not invent geometry or expressions without source morph material.
  • Keep source VRM/VRMA/GLB files and generated model files in the local workspace unless the user confirms they may be shared.
  • Keep reports focused on project-relative paths and model facts.
  • Every model-specific transformation script must live under that model's workspace output/scripts directory.
  • Run the self-review loop in harness/self-review-loop.md at least three times.

Required Outputs

For each target model, create an output folder containing:

  • extended VRM file with a new name,
  • INSPECTION.md,
  • PLAN.md,
  • EXPRESSIONS.md,
  • VERIFY.md,
  • SELF_REVIEW.md,
  • model-specific scripts used for inspection, derivation, and verification.

Required Expression Classification

For each requested expression, classify it as one of:

  • already_available
  • aliasable
  • derivable
  • unsupported

Unsupported is acceptable when the model lacks source morphs. Do not hide this.

Required Review Gates

  1. Inspection review before writing derivation code.
  2. Plan review before modifying any output VRM.
  3. Structural verification after derivation.
  4. Visual WebUI review after generation.
  5. Asset and license review before final response.

Final Response Requirements

Report:

  • input and output filenames,
  • VRM version and license metadata summary,
  • expressions added, aliased, already available, and unsupported,
  • verification result,
  • WebUI preview instructions,
  • any residual risks.

Read the full file on GitHub · 61 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. 6d ago First seen · 61 lines · 447 tokens per session scan A fe7eea435f69

Subscribe to this mod's changes

vrm-expression-agent-harness AGENTS.md is an instructions file published in the GitHub repository shinshin86/vrm-expression-agent-harness (20 stars, last pushed 2mo ago), licensed MIT. It adds 447 tokens to every session, about $0.0022 per session on Opus 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 2026-08-31.

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