What is nexusos AGENTS.md?

Repository-specific instructions for agents working on NexusOS, a local-first knowledge system that stores user-owned information in files.

They define the project's mission, release limits, isolation rules, naming conventions, and testing requirements.

How asimons81/nexusos configures Codex and OpenCode

Q: What is it for?

Use them before inspecting tasks, editing code, or changing documentation in the NexusOS project.

Reuse

Borrowing it

Nothing to install: this file belongs to asimons81/nexusos. 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/asimons81/nexusos/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/asimons81/nexusos

Made for: Codex, OpenCode.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/asimons81/nexusos/agents-md/github.svg)](https://agentmods.dev/instructions/asimons81/nexusos/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/asimons81/nexusos/agents-md"><img src="https://agentmods.dev/badge/instructions/asimons81/nexusos/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/asimons81/nexusos/agents-md"><img src="https://agentmods.dev/badge/instructions/asimons81/nexusos/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,779 This file is loaded in full into every session.

When invoked 1,779 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.

Model	Per session	Once invoked
Fable 5.1	$0.01779	$0.01779
Opus 5.5	$0.00712	$0.00712
Sonnet 5.5	$0.00356	$0.00356
Haiku 4.5	$0.00178	$0.00178

Measured 2mo ago against content hash b6fc1dbec418, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

nexusos 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 2mo 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 · 203 lines

How it starts

The opening of the file, as written. The whole thing — 203 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

This file defines the operating contract for AI coding agents working on NexusOS. Read it before inspecting tasks, editing code, or changing documentation.

Mission

NexusOS is a local-first knowledge operating system for AI agents. The v0.1 release must provide a small, deterministic, well-tested memory contract over files the user owns.

The repository is shipping stable v0.1.0. The planned core v0.1 feature scope shipped through the alpha/RC train. Preserve the frozen v0.1 contracts and route new product scope to the next release train.

The executable release plan lives in ROADMAP.md.

Isolation rules

These are non-negotiable:

Work only inside the NexusOS project directory.
Namespace all product state under CLI nexusos, package nexusos, environment variables NEXUSOS_*, and workspace state .nexusos/.
Never reference, import, inspect, or depend on private Nexus projects or personal knowledge stores.
Never hardcode personal names, paths, domains, credentials, or workspace content.
Tests must use synthetic fixtures and temporary directories.
Source documents are immutable unless a future, explicitly approved write system is implemented. v0.1 has no source-mutation feature.
Derived state must remain disposable and rebuildable from source files.

Architecture boundary

core (errors, models, path safety, configuration)
    ↓
workspace (initialization, identity, templates)
    ↓
indexing (discovery, parsing, graph, schema, migrations, database, lock, kernel)
    ↓
services (doctor, index, status, search, navigation, lint, serve, demo)
    ↓
cli (Typer and Rich adapters)

mcp (top-level adapter beside cli, importing services only)

Rules:

core must not import Typer, Rich, MCP, CLI, or service modules.
workspace may depend on core, never on CLI or MCP.
indexing may depend on core and workspace, never on CLI or MCP.
services owns reusable application behavior.
cli formats command input and output around services.
mcp is a top layer. It imports services, not indexing internals or CLI code.
CLI and MCP behavior should share service contracts rather than duplicate logic.

Read the full file on GitHub · 203 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.

2mo ago First seen · 203 lines · 1,779 tokens per session scan A b6fc1dbec418

Subscribe to this mod's changes

nexusos AGENTS.md is an instructions file published in the GitHub repository asimons81/nexusos (20 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 1,779 tokens to every session, about $0.0071 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.

ai-agents cli fts5 knowledge-management local-first markdown

nexusos AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
nexusos AGENTS.mdasimons81/nexusos	Instructions file	20	2mo ago	Apache-2.0	A	1,779	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

nexusos: Instructions file for Codex