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.
npx agentmods add instructions/ido-pluto/windows98-mcp/agents-mdgit clone --depth 1 https://github.com/ido-pluto/windows98-mcpWhat 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 | $0.01679 | $0.01679 |
| Opus 5 | $0.00839 | $0.00839 |
| Sonnet 5 | $0.00336 | $0.00336 |
| Haiku 4.5 | $0.00168 | $0.00168 |
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.
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_listwithout a target to discover all known VM connections and their state. Includevm_namein every guest-targeted MCP tool input and in theparamsobject 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
win98MCP tools when they are available. -
If only terminal/CLI access is available, use
npx windows98-mcp toolsto inspect every operation and its exact JSON schema, then use either:npx windows98-mcp call <method> --vm <name> --params '<JSON>' npx windows98-mcp rpc -
callis 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; userpcfor those. -
rpcis 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.replayedin 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_lockandvm_waitmatter only when an operator enables exclusive lock agents. In that mode, use the returned FIFO ticket afterVM_BUSY.- For a managed QEMU VM, use
host=10.0.2.2inWIN98CTL.INI; it is QEMU's user-network host gateway. Do not use guest127.0.0.1. The QEMU profile defaults includekernel-irqchip=off,hpet=off,usb=offandautoalways has an emulation fallback.
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.
- 2d ago First seen · 124 lines · 1,679 tokens per session scan A 20e1bd0e1316
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.
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