windows98-mcp AGENTS.md

A set of operating instructions for controlling Windows 98 virtual machines, which are computer simulations running an old Microsoft operating system. It explains how to name, find, connect to, and safely target each virtual machine.

In plain words
What is it for?
Discovering connected Windows 98 machines, selecting the right one, choosing available control tools, recovering connections, and handling concurrent work safely.
Why use it?
It reduces mistakes when several virtual machines share one connection, especially by requiring every operation to identify its target.

Instructions file for CodexOpenCode

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.

agentmods
npx agentmods add instructions/ido-pluto/windows98-mcp/agents-md
Clone the repo
git clone --depth 1 https://github.com/ido-pluto/windows98-mcp

Made for: Codex, OpenCode.

Per session 1,679 This file is loaded in full into every session.
When invoked 1,679 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 $0.01679 $0.01679
Opus 5 $0.00839 $0.00839
Sonnet 5 $0.00336 $0.00336
Haiku 4.5 $0.00168 $0.00168

Measured 2d ago against content hash 20e1bd0e1316, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

windows98-mcp 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 · 124 lines

How it starts

The opening of the file, as written. The whole thing — 124 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Windows 98 MCP and CLI operating rules

Target a named VM

  • One broker listener can accept multiple Windows 98 guests. Configure a stable, case-insensitively unique name for each guest in WIN98CTL.INI:

    [connection]
    host=10.0.2.2
    port=9898
    name=win98-lab-a
    
  • Use vm_list without a target to discover all known VM connections and their state. Include vm_name in every guest-targeted MCP tool input and in the params object of every JSON-lines RPC call, even when only one VM is connected. For CLI calls, pass --vm <name>.

  • VM names compare case-insensitively. A duplicate live name is rejected with VM_NAME_IN_USE; the existing connection remains authoritative.

  • Guest-targeted state and concurrency are per VM. Brokers in relay mode keep one upstream bridge per guest, so multiple named VMs can share both broker listeners and operate in parallel.

Choose an interface

  • Prefer the win98 MCP tools when they are available.

  • If only terminal/CLI access is available, use npx windows98-mcp tools to inspect every operation and its exact JSON schema, then use either:

    npx windows98-mcp call <method> --vm <name> --params '<JSON>'
    npx windows98-mcp rpc
    
  • call is for one self-contained operation. It creates a temporary session and force-cleans it on exit. It intentionally rejects terminal operations, mouse_down, and keyboard-down operations; use rpc for those.

  • rpc is a persistent JSON-lines session. Send one request per line as {"id":"unique-id","method":"method_name","params":{...}}; read matching JSON response lines. Keep it open for shell sessions, held input, input batches, and multi-step workflows. EOF force-cleans that RPC session.

  • For a remote broker, add --broker-host <ip> --broker-port <port>. File and directory paths always belong to the machine running the CLI, not the remote broker host.

Connection, recovery, and concurrency

  • The guest dials the host every two seconds. The MCP/CLI process stays usable when the VM is powered off. Guest tools return retryable VM_OFFLINE; retry after the guest reconnects without recreating the Codex task or CLI session.
  • The adapter resumes short broker connection losses automatically and may replay interrupted work at least once. A replay can duplicate clicks, commands, or writes; inspect recovery.replayed in the result.
  • Parallel operation is the default. The broker FIFO-serializes protocol calls independently per VM, so different named VMs can make progress at the same time. Mouse, keyboard, focus, clipboard, and screen state remain shared within each VM; coordinate interactive UI work targeting the same VM.
  • vm_lock and vm_wait matter only when an operator enables exclusive lock agents. In that mode, use the returned FIFO ticket after VM_BUSY.
  • For a managed QEMU VM, use host=10.0.2.2 in WIN98CTL.INI; it is QEMU's user-network host gateway. Do not use guest 127.0.0.1. The QEMU profile defaults include kernel-irqchip=off,hpet=off,usb=off and auto always has an emulation fallback.

Read the full file on GitHub · 124 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 First seen · 124 lines · 1,679 tokens per session scan A 20e1bd0e1316

Subscribe to this mod's changes

windows98-mcp AGENTS.md is an instructions file published in the GitHub repository ido-pluto/windows98-mcp (2 stars, last pushed 13d ago), licensed MIT. It adds 1,679 tokens to every session, about $0.0084 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.