ci(test): split integration into per-backend jobs

Add separate `integration-docker` and `integration-firecracker` jobs,
each with an explicit BOT_BOTTLE_BACKEND env var, so the backend used
is visible in CI output and skipped backends surface as a distinct job
rather than silent unittest.skip lines.

- integration-docker: ubuntu-latest, BOT_BOTTLE_BACKEND=docker
- integration-firecracker: [self-hosted, kvm], BOT_BOTTLE_BACKEND=firecracker,
  same-repo PRs + push + workflow_dispatch only (untrusted fork PRs do
  not execute on the privileged KVM runner)
- coverage: same same-repo restriction; refs #414 for the planned
  follow-up that moves coverage to ubuntu-latest via artifact combination

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/research/hn-agent-safety-discourse-july-2026.md

@@ -0,0 +1,308 @@
+# HN discourse on agent sandbox safety — June/July 2026
+
+A survey of community opinion and notable security disclosures on Hacker
+News and adjacent sources over June–July 2026. The question: what does
+the current discourse say about whether sandboxes are sufficient for
+agentic AI safety, and where does bot-bottle land against the issues
+being raised?
+
+Research conducted 2026-07-18.
+
+## Summary
+
+The past month marks a turning point in community opinion. Earlier in
+2026, the debate was mostly "which sandbox tool is best?" By June–July,
+a cascade of critical CVEs and novel attack classes has shifted the
+framing to "sandboxes are not enough — what else do you need?" The
+attacks that drove this shift are structurally distinct: most route
+through legitimate, trusted channels (Sentry issues, MCP descriptions,
+README files) rather than exploiting the isolation boundary directly.
+
+bot-bottle's architecture holds up well against the direct-escape class
+(Firecracker/Apple Container default backends, credentials never in the
+agent's env, harness entirely on the host). The remaining gap is prompt
+injection — attacker-controlled data interpreted as model instructions.
+Egress controls and prompt injection defenses are orthogonal: egress
+limits what the agent can *send out*; injection is about what it is
+*told to do*. The two don't substitute for each other. Inside a tightly-
+egressed sandbox a successful injection can't exfiltrate to unknown
+hosts, but it can still corrupt the work product, push malicious commits
+past a secret scanner, or use allowlisted channels for exfiltration.
+Those residual risks are addressed below.
+
+## The sandboxing boom sets the stage
+
+The preceding months generated a wave of sandbox tooling. A March 28
+Ask HN thread
+([#47444917](https://news.ycombinator.com/item?id=47444917)) catalogued
+the explosion: E2B, AIO Sandbox, AgentSphere, Yolobox, Exe.dev,
+AgentFence, DenoSandbox, Capsule (WASM), ERA, Vibekit, Daytona, Modal,
+Nono, and more — all launched within roughly 12 months. A parallel March
+9 thread ([#47185250](https://news.ycombinator.com/item?id=47185250))
+surveyed what developers were actually deploying: "containers or YOLO"
+dominated. The honest community mood was that most teams hadn't solved
+this and were shipping anyway.
+
+## The June–July attack cascade
+
+Six attack patterns broke in quick succession. Together they form the
+argument that the community's framing was wrong: the threat model for
+agents isn't just "code that escapes its container" — it's also prompt
+injection, where attacker-controlled data is interpreted as model
+instructions regardless of whether any isolation boundary was crossed.
+Sections 2–4 below are all the same attack class; the "trusted channel"
+label describes the delivery vector, not a different threat.
+
+### 1. Sandbox escape CVEs (DuneSlide, CVE-2026-39861)
+
+Cato AI Labs disclosed **DuneSlide** (CVE-2026-50548/50549, CVSS 9.8),
+a pair of flaws in Cursor 2.x. CVE-2026-50548 abuses the sandbox's
+`working_directory` parameter to point writes at system files; CVE-26-50549
+exploits a symlink-resolution fallback that fails open. Both start with
+a prompt injection and end in sandbox escape — and Cato's framing was
+blunt: "each CVE defeats a different guardrail; the problem is
+structural, not a string of one-offs."
+
+Claude Code's own sandbox had a similar escape this year:
+**CVE-2026-39861** (symlink flaw). The CurXecute/MCPoison/CVE-2026-26268
+chain from Cursor added a poisoned Slack message, a swap-after-approval
+MCP config, and a Git hook as three more entry points in the same
+attack class.
+
+All patched, but the pattern holds: any application-level sandbox that
+takes attacker-influenced values as path parameters is reachable from a
+prompt injection.
+
+### 2. Prompt injection via MCP data (Agentjacking)
+
+Tenet's "Agentjacking" technique planted a fake bug report in Sentry's
+MCP output. When an agent queries Sentry to fix open issues, the
+malicious event is rendered as structured content visually
+indistinguishable from a real Sentry event, and the agent executes the
+embedded instructions with the developer's full privileges. Hit rate
+across Claude Code and Cursor: **85%**. The route is entirely through a
+legitimately-authorized MCP channel — no isolation boundary is crossed;
+the injection arrives inbound through a channel the sandbox explicitly
+trusts.
+
+The Cloud Security Alliance's summary: treat observability, bug-report,
+and integration data as **untrusted agent input**, not neutral
+development metadata.
+
+### 3. README-embedded prompt injection
+
+A July disclosure showed malicious instructions hidden in `README.md`
+— a file that receives no trust prompt and requires no elevated access.
+When asked point-blank whether the repo held hidden instructions, both
+Claude Sonnet 4.6 and GPT-5.5 said no. A payload written for Sonnet
+4.6 transferred unchanged to Sonnet 5, Opus 4.8, and GPT-5.5. The
+attack surface is every repo an agent is asked to work in.
+
+### 4. Prompt injection via MCP tool descriptions
+
+Microsoft research (June 30) showed that attacker-controlled MCP tool
+description fields can silently redirect agent behavior. The injection
+is embedded in metadata the model reads during tool selection — before
+any sandbox enforcement or egress check runs, and entirely on the
+inbound path that egress controls cannot touch.
+
+### 5. MCP STDIO command injection (10 CVEs)
+
+OX Security disclosed a systemic command injection class in Anthropic's
+MCP protocol, covering 10 CVEs across multiple coding agents. The
+Windsurf case (CVE-2026-30615): processing attacker-controlled HTML
+causes the agent to auto-register a malicious MCP STDIO server and
+execute arbitrary commands with no further user interaction.
+
+### 6. LiteLLM gateway compromise (CVE-2026-40217, CVE-2026-42271)
+
+CVE-2026-40217 exposes LiteLLM's guardrail sandbox via `exec()` with no
+source filtering. CVE-2026-42271 (exploited in the wild, added to CISA's
+KEV catalog) lets callers spawn subprocesses through MCP preview
+endpoints. The threat extends to any agent routed through a compromised
+LiteLLM proxy: the proxy can swap model responses for forged tool calls
+in transit, giving the attacker a reverse shell from the developer's
+machine.
+
+## HN community opinion clusters
+
+**"Move enforcement to the kernel, not the app"** — the Nono Show HN
+([#46849615](https://news.ycombinator.com/item?id=46849615)) and a
+kernel-sandbox thread
+([#47066574](https://news.ycombinator.com/item?id=47066574)) both argued
+that application-layer sandboxes are inherently bypassable by the code
+they're sandboxing. The academic framing, from *Red-Teaming the Agentic
+Red-Team* ([arXiv 2606.24496](https://arxiv.org/pdf/2606.24496)):
+"enforcement should occur at the OS level via the kernel refusing system
+calls that violate policy at runtime — not pre-execution argument
+validation in tool calls."
+
+**"The harness belongs outside the sandbox"** — a May thread
+([#47990675](https://news.ycombinator.com/item?id=47990675)) converged
+on clean architectural separation: harness in one VM, tool execution in
+another. Top comment: "having the harness in one VM, and tool use applied
+to user data in another, is about as safe as you can be at present."
+Several replies described a hypervisor-like policy layer — sitting outside
+both VMs — as the right long-term model.
+
+**"Sandboxes are too coarse-grained"** — a Feb thread
+([#47006445](https://news.ycombinator.com/item?id=47006445)) argued
+that VMs don't answer the real question: knowing whether an agent
+*should* be sending an email or making a transaction. "Everything's just
+in the same big box." This framing picked up traction through June–July
+as the trusted-channel attacks dominated.
+
+**"MCP's trust model is the real problem"** — the month's recurring
+theme. MCP by design gives agents access to authorized external services.
+Once a trusted channel delivers a malicious payload, filesystem sandboxing
+is irrelevant. The community call: treat all MCP tool metadata and return
+values as untrusted input subject to policy validation before ingestion,
+and disable automatic MCP server loading from untrusted repositories.
+
+## How bot-bottle addresses these issues
+
+### What it covers well
+
+**Direct sandbox escape (CVEs, container breakout)**
+
+bot-bottle's default backends are Firecracker microVM (KVM Linux) and
+Apple Container (macOS). Both run the agent in a separate VM with a
+dedicated kernel — the container-escape CVE class (Dirty Pipe, runc
+escapes, DuneSlide's path-parameter abuse) requires escaping a real
+hypervisor boundary, not just a namespace. On the legacy Docker backend,
+gVisor auto-detection provides a userspace syscall barrier for hosts where
+neither KVM nor Apple Container is available.
+
+The bot-bottle process itself runs entirely on the host, outside the VM.
+This is the "harness outside the sandbox" architecture the HN thread
+converged on as best practice. The bottle manifest, egress rules, and
+secrets never enter the agent VM.
+
+**Credential theft on sandbox escape**
+
+Even on a successful VM/container escape, the agent has nothing useful
+to steal. Credentials are injected in-flight by the gateway proxy
+(`auth.scheme` / `auth.token_ref` in the egress route config) — `printenv`
+inside the agent shows proxy URLs only. The git-gate similarly holds the
+upstream SSH credential on the host; the agent pushes through a
+gitleaks-scanned daemon that forwards clean refs upstream. An escaped
+agent gets the host filesystem, not the keys.
+
+**Orphaned-agent credential risk**
+
+bot-bottle is explicitly ephemeral: when the agent exits, `cli.py` tears
+down every gateway and both networks — nothing persists between runs. The
+agent never holds credentials, so there is nothing to orphan.
+
+**MCP config redirection / STDIO auto-registration**
+
+The trust boundary at `$HOME` means bottles live only under
+`~/.bot-bottle/bottles/` — a cloned repo cannot add egress routes or
+redirect env vars to attacker hosts (the design rationale is in
+`docs/prds/0011-per-file-md-manifest.md`). Auto-registering a malicious
+MCP STDIO server from within the agent is still sandboxed by the VM, and
+any outbound calls from that server must pass the egress allowlist and
+outbound DLP scanner.
+
+**Outbound exfiltration (any injection class)**
+
+Whatever triggers the agent — README injection, Agentjacking, MCP
+description poisoning — the final step in most attacks is exfiltration.
+bot-bottle's egress allowlist is default-deny with a per-bottle host
+allowlist; unknown hosts get a hard 403. Outbound DLP scanning
+(`outbound_detectors: [token_patterns, known_secrets]`) catches tokens
+and secrets in outbound bodies; the `supervise` policy (default for
+manifest routes) holds the request for operator approval rather than
+silently blocking it. Together these limit what a successful injection
+can *do* even if it succeeds at the model layer.
+
+**LiteLLM / compromised-proxy attacks**
+
+bot-bottle does not use LiteLLM. The model API route (e.g.
+`api.anthropic.com`) is an auto-injected provider route on the egress
+allowlist; the agent dials the gateway, not the model API directly.
+A compromised third-party proxy is not in the architecture.
+
+### Where it is weaker
+
+**Prompt injection**
+
+Egress controls and prompt injection defenses are orthogonal. Egress
+limits what the agent can *send out* (outbound leg); prompt injection
+is about what attacker-controlled data *tells the agent to do* (inbound
+leg). The two don't substitute for each other and must be treated
+separately.
+
+The inbound DLP scanner (`inbound_detectors: [naive_injection_detection]`)
+is the only runtime defense against injection arriving through allowlisted
+channels — Sentry MCP responses, MCP tool descriptions, README content.
+It is explicitly pattern-matching and will not catch a sufficiently
+crafted payload. There is no semantic / intent-level gate between what
+the model decides and what the agent executes.
+
+**Blast radius within the permitted scope**
+
+Inside a tightly-egressed sandbox a successful injection can't
+exfiltrate to unknown hosts, but it still has real options:
+
+- *Work product corruption.* The agent can modify, delete, or backdoor
+  files in the working directory. This is within its permitted scope;
+  egress controls have nothing to say about it.
+
+- *Malicious commits past the git-gate.* The git-gate scans outbound
+  refs for secrets (gitleaks), not for semantic code intent. A prompt-
+  injected agent can commit subtly malicious code — logic bombs,
+  backdoored auth paths, code that exfiltrates data through the
+  application's own HTTP clients at runtime — that looks clean to a
+  secret scanner.
+
+- *Exfiltration through allowlisted channels.* If an attacker knows or
+  can predict what hosts are in the egress allowlist, those channels are
+  available for exfiltration. A GitHub remote being allowlisted means
+  "push to an attacker-controlled fork" is viable. A logging endpoint
+  being allowlisted means structured data can leave through it. The
+  outbound DLP scanner catches credential tokens and known secrets but
+  not arbitrary business data.
+
+- *Dependency installation within the sandbox.* An agent that runs
+  `npm install` or `pip install` on attacker-specified packages executes
+  code inside the sandbox with the same capabilities the agent has:
+  filesystem access, tool calls, calls to allowlisted hosts. Supply chain
+  injection via package names is in the same injection family, triggered
+  by the same prompt-injection path.
+
+### What would close the remaining gaps
+
+The blast-radius risks above point at two distinct mitigations that
+don't yet exist in bot-bottle:
+
+- *Outbound intent classification.* The egress addon today scans
+  outbound request content for token patterns. What it lacks is
+  awareness of context — it can't distinguish "agent is pushing a
+  legitimate commit" from "agent was injected and is pushing a backdoor."
+  The `supervise` policy is already the right shape for human-in-the-loop
+  review on sensitive outbound actions; extending it with context from
+  the agent's recent tool calls (what files were touched, what was the
+  triggering task) would narrow the gap.
+
+- *Semantic code review on git push.* gitleaks is the wrong tool for
+  catching injected logic. A review step on outbound commits — even a
+  simple diff summary surfaced in `cli.py supervise` before the push is
+  forwarded — would close the malicious-commit path without requiring
+  the agent to be fully trusted.
+
+## Sources
+
+- [Ask HN: The new wave of AI agent sandboxes? (Mar 2026)](https://news.ycombinator.com/item?id=47444917)
+- [OK, let's survey how everybody is sandboxing AI coding agents (Mar 2026)](https://news.ycombinator.com/item?id=47185250)
+- [The agent harness belongs outside the sandbox (May 2026)](https://news.ycombinator.com/item?id=47990675)
+- [Show HN: Nono – Kernel-enforced sandboxing for AI agents (Feb 2026)](https://news.ycombinator.com/item?id=46849615)
+- [Kernel-enforced sandbox for AI agents, MCP and LLM workloads (Feb 2026)](https://news.ycombinator.com/item?id=47066574)
+- [Sandboxes will be left in 2026 (Feb 2026)](https://news.ycombinator.com/item?id=47006445)
+- [Critical Cursor Flaws / DuneSlide – The Hacker News](https://thehackernews.com/2026/07/critical-cursor-flaws-could-let-prompt.html)
+- [Agentjacking Attack – The Hacker News](https://thehackernews.com/2026/06/agentjacking-attack-tricks-ai-coding.html)
+- [Friendly Fire: AI Agents Built to Catch Malicious Code – The Hacker News](https://thehackernews.com/2026/07/friendly-fire-ai-agents-built-to-catch.html)
+- [Microsoft Warns Poisoned MCP Tool Descriptions – The Hacker News](https://thehackernews.com/2026/06/microsoft-warns-poisoned-mcp-tool.html)
+- [MCP STDIO Command Injection Advisory – OX Security](https://www.ox.security/blog/mcp-supply-chain-advisory-rce-vulnerabilities-across-the-ai-ecosystem/)
+- [LiteLLM Vulnerability Chain – The Hacker News](https://thehackernews.com/2026/06/litellm-vulnerability-chain-lets-low.html)
+- [Red-Teaming the Agentic Red-Team (arXiv 2606.24496)](https://arxiv.org/pdf/2606.24496)