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office-open-xml-viewer: Instructions file for Codex

AGENTS.md

office-open-xml-viewer AGENTS.md is an instructions file for Codex, OpenCode from yukiyokotani/office-open-xml-viewer. It costs 4,095 tokens per session, scanned A, original, MIT.

Repository instructions for a browser-based viewer for DOCX, XLSX, and PPTX documents. They describe the Rust, WebAssembly, TypeScript, and Canvas parts of the project, along with its development workflow.

In plain words
What is it for?
Use them when fixing bugs, adding document-rendering features, changing shared code, or verifying work in this office-document viewer.
Why use it?
They give coding agents the project context and rules for making, testing, and reviewing changes safely. They also explain how to work with separate packages and pull requests.

Instructions file for CodexOpenCode

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

This is yukiyokotani/office-open-xml-viewer's own configuration. It tells Codex and OpenCode how to work on office-open-xml-viewer 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 office-open-xml-viewer configures →

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is ln -s ../../../spec spec.

not rated 790repo +14 changed 2d ago A scan 4,095 tokens original MIT
View source ↗ yukiyokotani/office-open-xml-viewer ooxml.silurus.dev
Reuse

Borrowing it

Nothing to install: this file belongs to yukiyokotani/office-open-xml-viewer. 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/yukiyokotani/office-open-xml-viewer/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/yukiyokotani/office-open-xml-viewer

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/yukiyokotani/office-open-xml-viewer/agents-md"><img src="https://agentmods.dev/badge/instructions/yukiyokotani/office-open-xml-viewer/agents-md/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.

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Per session 4,095 This file is loaded in full into every session.
When invoked 4,095 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.04095 $0.04095
Opus 5 $0.02048 $0.02048
Sonnet 5 $0.00819 $0.00819
Haiku 4.5 $0.00409 $0.00409

Measured 2d ago against content hash 5676ec220bd8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

office-open-xml-viewer 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 2d 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 · 384 lines

How it starts

The opening of the file, as written. The whole thing — 384 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Instructions

This file is the canonical workflow for AI coding agents working on this repository. Tool-specific files such as CLAUDE.md may add supplements, but they must not contradict this file.

Project

office-open-xml-viewer renders OOXML documents (docx, xlsx, pptx) to browser Canvas. The implementation is a Rust/WASM parser layer plus TypeScript Canvas renderers and viewers.

Important directories:

  • packages/core/ — shared rendering primitives and shared TypeScript helpers.
  • packages/ooxml-common/ — shared Rust parsing/model helpers.
  • packages/docx/ — DOCX parser, renderer, viewer, and tests.
  • packages/xlsx/ — XLSX parser, renderer, viewer, and tests.
  • packages/pptx/ — PPTX parser, renderer, viewer, and tests.
  • site/ — public site.
  • .storybook/ — unified Storybook config.

Standard Development Flow

Use this flow for ordinary bug fixes and feature work:

  1. Start from main and run git pull --ff-only.

  2. If the checkout is dirty, preserve unrelated work before switching or pulling. Prefer git stash push -u -m <clear-message> for work that appears to belong to another session.

  3. Create a feature branch. Use codex/<topic> for Codex work when possible; otherwise follow the repository's existing branch naming.

  4. When creating or entering a Codex/Claude worktree, make the root checkout's ignored spec/ directory available from that worktree as a local symlink. For the standard .claude/worktrees/<name> layout, run:

    ln -s ../../../spec spec

    If the worktree lives elsewhere, create spec as a symlink to the main local checkout's spec/ directory. Do not copy or commit the specification files.

  5. Work with TDD for bug fixes:

    • explore the failing sample or behavior,
    • add a focused failing test,
    • make it pass,
    • refactor only where it reduces real complexity.

  6. Verify with the narrowest meaningful tests first, then broader checks when the touched surface warrants it.

  7. Commit only the intended source/docs/test files. Do not commit private samples or generated local artifacts.

  8. Push the feature branch, create a PR, wait for checks when practical, and merge with a merge commit. Do not squash.

Read the full file on GitHub · 384 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. 2d ago Changed · +7 tokens per session 5676ec220bd8
  2. 5d ago Changed · +50 lines · +676 tokens per session c7f54f2276b6
  3. 10d ago First seen · 334 lines · 3,412 tokens per session scan A c05c41e2343a

Subscribe to this mod's changes

office-open-xml-viewer AGENTS.md is an instructions file published in the GitHub repository yukiyokotani/office-open-xml-viewer (790 stars, last pushed yesterday), licensed MIT. It adds 4,095 tokens to every session, about $0.0205 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 2026-08-30.

TypeScriptdocxooxmlooxml-viewerpptxxlsx
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