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 skills add batteryshark/rekit --skill emulation-sessiongit clone --depth 1 https://github.com/batteryshark/rekitWrote 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.
[](https://agentmods.dev/skills/batteryshark/rekit/emulation-session)<a href="https://agentmods.dev/skills/batteryshark/rekit/emulation-session"><img src="https://agentmods.dev/badge/skills/batteryshark/rekit/emulation-session/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.
<a href="https://agentmods.dev/skills/batteryshark/rekit/emulation-session"><img src="https://agentmods.dev/badge/skills/batteryshark/rekit/emulation-session.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00072 | $0.00573 |
| Opus 5.5 | $0.00029 | $0.00229 |
| Sonnet 5.5 | $0.00014 | $0.00115 |
| Haiku 4.5 | $0.00007 | $0.00057 |
Grade A, and why
emulation-session 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 1mo 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 — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Stateful Emulation Session
Use a caller-chosen session directory as durable emulator state. Each invocation locks the directory, restores the prior state, performs one operation, and saves the result. This keeps the skill stateful through Rekit's ordinary CLI and MCP surfaces without a second server or a background daemon.
Workflow
- Create a session with a raw code blob and
--engine unicorn, or a full binary, matching rootfs, and--engine qiling. - Inspect or change registers and memory before execution when needed.
- Add bounded observation hooks, enable tracing selectively, then
steporrun. - Save a named snapshot before exploring a branch; restore it to try another path.
- Read the trace and state, then mark the session closed when the investigation ends.
rekit run emulation-session .rekit/emu/decoder create \
--engine unicorn --input ./decoder.bin --arch x64 --trace --format json
rekit run emulation-session .rekit/emu/decoder step --count 4 --format json
rekit run emulation-session .rekit/emu/decoder read-registers --format json
rekit run emulation-session .rekit/emu/decoder save-snapshot --label before-branch --format json
Read references/operations.md for the action and option
matrix, engine-specific behavior, persistence format, and safety boundaries.
Rules
- Treat session directories and Qiling snapshot files as trusted local state; do not restore a session supplied by an untrusted party.
- Keep instruction and trace limits finite. Emulation is containment, not proof that a target is harmless.
- Use
emulate-codeorqiling-emulatefor one-shot work. Use this skill only when state must survive multiple operations. - Use separate session directories for parallel investigations.
closepreserves evidence and marks the session closed; it never deletes files.- Every Unicorn result records backend provenance. On Apple Silicon, native and Rosetta x86_64 are capability-probed separately; a host signal is returned as a tooling-capability error and never as guest behavior.
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 1mo ago First seen · 49 lines · 72 tokens per session scan A 40e5a03d7be1
emulation-session is a skill published in the GitHub repository batteryshark/rekit (20 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 72 tokens to every session and 573 once invoked, about $0.0003 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.
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