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docs/security/audit-claude-code-meta.md

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Meta-audit — the Claude Code session that performed these audits

A self-audit, completing the "audit the auditor" loop. Honest accounting of what this assistant has seen during the audit / analysis work and where that data went.

Scope

This audit covers the Claude Code session running on the Proxmox host (/root/.claude/projects/-root/) on 2026-05-20 and 2026-05-21, from the message > finish up for today. last task: the attached conversation was run on our lobehub… onward. The work product of that session is the three audit reports in this directory.

What the assistant processed

Input Content Source
Transcript A 75fb06e8-Lumen_TR004_Test_Run_Analysis.json (255 KB, 60 messages, model qwen3.5-397b-a17b) User-uploaded
Transcript B ec5fba44-Analyzing_LUMEN_TR004_Test_Data.json (205 KB, 41 messages, model qwen3-coder-30b-a3b-instruct) User-uploaded
SSH + pct exec on nuc container env vars, docker ps, proxy_server_config.yaml, gateway_tokens.json (first chars only) Live homelab inspection
https://docs.hpc.gwdg.de/services/ai-services/saia/index.html SAIA public docs WebFetch (Anthropic-mediated)

The Lumen transcripts contain DLR-context identifiers (LUMEN, P3-Lampoldshausen, LOX/LCH4, TR-003/004/006), anomaly metadata (fuel turbopump vibration spike at t=8s, ~12 g rms), and chemistry/test-bench naming. The assistant quoted portions of these in chat output and in the audit reports.

Where that data went

flowchart LR
  user(["Operator"]) --> cc["Claude Code CLI<br/>on Proxmox host"]
  cc -->|every prompt + tool result<br/>+ assistant turn| api[(api.anthropic.com<br/>Anthropic API)]
  cc -->|ssh / pct / docker via shell| home["nuclide.systems<br/>(LAN-only)"]
  cc -->|WebFetch SAIA public docs| saiadocs[(docs.hpc.gwdg.de<br/>via Anthropic proxy)]
  cc -->|FLUX image-gen MCP| flux[(image-gen MCP backend<br/>Anthropic-side)]

  classDef leak fill:#5a2a2a,stroke:#c44,color:#fcc
  classDef ok fill:#234c2a,stroke:#4c8,color:#cfc
  classDef external fill:#5a4a2a,stroke:#cc8,color:#fec
  class api,flux leak
  class home ok
  class saiadocs external

This Claude Code session is itself an outbound channel. Every assistant turn, including those that quoted Lumen transcript content, was a request to api.anthropic.com. The full session is:

Channel What flows Trust
Claude API (api.anthropic.com) Full prompts + tool results + audit text the assistant produced. ~60+ turns this session. Includes verbatim LUMEN identifiers in audit body, snippets of transcript content, snippets of LiteLLM config, snippets of gateway_tokens.json (one token prefix), Vaultwarden plaintext secret (handed back to operator, then echoed in subsequent context). Commercial vendor (Anthropic). Operator chose to use Claude Code; informed-consent leak.
WebFetch (also via Anthropic) The URL https://docs.hpc.gwdg.de/services/ai-services/saia/index.html was fetched server-side by Anthropic, content returned to the assistant. Outbound from Anthropic to GWDG (public doc; no sensitive payload). Public web fetch, no sensitive outbound payload.
Image-gen MCP Prompt strings (containing brief LUMEN reference in one attempted illustration: "Python with LUMEN identifiers leaked to commercial cloud"). Backend is Anthropic-side per the MCP integration. Same Anthropic boundary.
SSH / pct / shell Authenticated to operator's own infrastructure. LAN, no leak.
Sub-agents (Pocket-ID audit, CT inventory, etc.) Ran on Anthropic's infrastructure — each got the relevant context for its narrow task. Same trust boundary as the main session. Anthropic.

Specific data this assistant sent to Anthropic

Across the audit work in this session, the following types of data were in the prompt/response stream to api.anthropic.com:

  • Lumen test analysis identifiers: LUMEN TR-004, P3-Lampoldshausen, LOX/LCH4, Fuel Turbopump Vibration Spike at t=8.0s, bearing replaced, test campaign dates.
  • Tool-call inventories (counts, MCP names, plugin identifiers) from both transcripts.
  • A snippet of gateway_tokens.json content (the SUB UUID and one truncated token preview) when auditing the gateway.
  • The plaintext Vaultwarden secret HvUJYUxCGLrSoDY2g24NJI5anM70xXwcsd3e3itJ (issued by the agent, surfaced in chat for the operator to save — operator saved it to Vaultwarden, but it remains in this session's context).
  • Pocket-ID OIDC client identifiers (UUID prefixes, names, callback URLs).
  • Internal IPs / CT layout (192.168.1.x).
  • Snippet of LiteLLM proxy_server_config.yaml showing fallback chains.

Threat model honesty

The act of running this audit using Claude Code is itself a higher-bandwidth leak than the leak it audited. Hours of conversation about LUMEN-context data went to Anthropic; the original Lumen TR-004 cloud-sandbox breach was ~1,500 lines of Python.

This is a deliberate trade-off:

  • Anthropic has stronger contractual guarantees than codesandbox.io (zero-data-retention API plans exist; Anthropic publishes a clear DPA).
  • The operator chose Claude Code consciously, knowing all prompts are API-bound.
  • It is not free. The work product is excellent; the data exposure is real.

Mitigations for future audit work

Option Pros Cons
Continue using Claude Code Best-in-class tooling, doctrine + memory carry across sessions, sub-agents in parallel All audit context goes to Anthropic
Use a local-only agent (e.g. gpt-oss-120b in workspace via Coder) Zero off-host audit data Far weaker capability; no rich tool-use; no memory; manual orchestration
Air-gap the work on a non-internet-connected host Strongest privacy No web fetches; no API; doctrine doesn't bootstrap; pace ~10x slower
Hybrid: Claude Code for general infra; air-gapped local agent for Lumen-specific prompts Best of both Process discipline required; operator decides routing per chat

For LUMEN-specific deep analysis going forward, the hybrid path is the rational one: do schema/topology/code work in Claude Code (no Lumen payload needed); do data-touching analysis in a Coder workspace with the mcp-sandbox template + a local LLM. The S3 artifact hub (planned) enables both surfaces to share visualization output without ever exposing raw data.

Recommendations as session policy

  1. For any chat that will reference Lumen/Shepard data, switch to the air-gapped / local-LLM path. Don't mix.
  2. Strip secrets from chat replies aggressively. The Vaultwarden plaintext secret didn't need to be displayed; the agent could have written it to a tmpfs file and pointed the operator at it.
  3. Tag this and future audit transcripts in /docs/security/transcripts/ with a "contains DLR-context data" header so the policy is visible to anyone reviewing them.

See also: data-leak-audit-comparison.md (the cross-session comparison), data-leak-audit-2026-05-20-tr004-cloud-sandbox.md, data-leak-audit-2026-05-21-tr004-artifacts.md.