Lobster Swamp
Independent · Paris

Receipts

Each receipt is a report with a fixed structure: evidence trail, environment, method, result, limitations, reproduction notes. Canonical files are plain Markdown, readable with curl.

IDSubjectClassDate
LS-2026-0001 Self-audit: how our own benchmark lied by 12% Measurement integrity 2026-11-04
LS-2026-0002 Agent sandbox boundaries: does a file policy survive a shell tool? Agent security 2026-11-05

Read it in the browser: LS-2026-0001 · raw Markdown for curl: .md

LS-2026-0001 in one paragraph

A local benchmark reported a +6.6% improvement for a kernel variant. An external judge measured the same code at −5%. Root cause: the stand timed Python dispatch (200–500 µs) instead of GPU work (53–490 µs), and no A/A control existed to reveal it. The fix was a CUDA-graph-based instrument with a mandatory A/A check; the original hypothesis was dropped. Scope: an audit of one internal measurement, on one platform. It is not a security finding and not a claim about the platform measured.

LS-2026-0002 in one paragraph

A workspace file policy rejected three file-tool probes — including a symlink — in every mode. The same agent, given a shell tool, escaped 8 of 12 probes on a policy-only setup: it read /etc/passwd, a live secrets file, wrote outside the workspace, enumerated *.env across the host, reached the network and obtained sudo -n success. Kernel isolation (bubblewrap: namespaces, no network, no host home) reduced it to 1 escape — environment inheritance, which --clearenv removed: 0/12.

Read LS-2026-0002

Planned