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 commands/thrashr888/agentkernel/start-stopgit clone --depth 1 https://github.com/thrashr888/agentkernelWhat 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 | $0.00000 | $0.01557 |
| Opus 5 | $0.00000 | $0.00779 |
| Sonnet 5 | $0.00000 | $0.00311 |
| Haiku 4.5 | $0.00000 | $0.00156 |
Grade A, and why
start-stop 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 — 245 lines — stays where its author put it; the contents beside it link to each section on GitHub.
agentkernel sandbox start / stop / pause / resume / fork
Manage the lifecycle of persistent sandboxes.
start and stop are the portable lifecycle operations. Firecracker sandboxes
on x86_64 Linux/KVM also support full-state pause, resume, and fork, which
preserve guest memory and process state.
start
Start a stopped sandbox.
Firecracker sandboxes are started through the long-running local API server so
the VM process survives after the CLI exits. Run agentkernel serve first;
AGENTKERNEL_PORT selects a non-default local port. If the server requires an
API key, set AGENTKERNEL_API_KEY for delegated CLI requests.
Each ordinary Firecracker start owns an AgentKernel-managed writable rootfs lineage. The opaque lineage reference is stored with the sandbox state and is reopened after stop, so guest filesystem changes survive a cold start.
Set AGENTKERNEL_ROOTFS_COW_MAX_BYTES to a host-wide logical-byte cap for
durable Firecracker writable images. A new start fails before copying its base
image when existing COW images plus that image would exceed the cap. This is a
storage headroom guard, not a tenant quota; it applies to every local
Firecracker sandbox and counts stopped lineages as well as running ones.
Before delegating, the CLI resolves the saved agentkernel.toml permissions
and startup file injections. It stores that resolved configuration in a private
host manifest and sends only an unguessable one-shot reference in the local
start request. The manifest is bound to the sandbox UUID and owner, consumed on
the first attempt, expires after five minutes, and is scrubbed on removal. A
valid reference can authorize the server's first claim of an unowned local
sandbox even after the server restarted or previously inspected it. This
preserves the selected profile, network and mount behavior, resource limits, and
file contents while the server retains VM ownership, without exposing a public
capability-escalation payload.
Usage
agentkernel sandbox start [OPTIONS] <NAME>
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 · 245 lines · 0 tokens per session scan A 377560973505
start-stop is a command published in the GitHub repository thrashr888/agentkernel (58 stars, last pushed 3d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,557 tokens. 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.
Other commands, from other repositories
diagnose
Run sivtr doctor to check the environment, then investigate any failing checks.
test-changed
Run the full quality gate on only the files changed since branching from main.
test_mcp
Test all rust-docs-testing tools found in @rust-docs-mcp/src/service.rs.
update_mcp_tools_list
Read the rust-docs-mcp/src/service.rs module and ensure that the README.md and the rust-docs-mcp/install.sh files have up to date lists of the tools available in the MCP.
review
You are an expert code reviewer. Your job is to review code changes and provide actionable feedback.
speckit.git.feature
Create a feature branch with sequential or timestamp numbering.