Software replay · AgentLeak 0.16.0 · 2026-09-27

Pattern matching calls 31% of real leaks clean.

Run over the 266 scenarios bundled with AgentLeak 0.16.0. Every number below is produced by a script in the repository, with no model in the loop, so re-running that release and configuration reproduces this snapshot.

The published paper evaluates 1,000 research scenarios and 4,979 model traces; read those results separately. Latest verified software release: 0.17.0.

266scenarios measured
69scored a perfect 100/100 by patterns alone
51%of real leaks would not block a CI gate
261leaks that never touched the final answer

Where a leak actually travels

Of the 261 scenarios that leak, 261 leak on internal channels only — the final answer stays clean in every one of them. An audit that reads the output alone reports those as passing.

98.5%tool_call — leaked in 257 of 261 leaking scenarios
15.7%shared_memory — leaked in 41 of 261 leaking scenarios
15.3%log — leaked in 40 of 261 leaking scenarios
5%inter_agent_message — leaked in 13 of 261 leaking scenarios
5%generated_file — leaked in 13 of 261 leaking scenarios
Read this honestly

This measures the bundled corpus, not live agents. These scenarios are built to exercise internal channels, so the internal-leak rate is partly by construction — it is the shape of the failure that matters, not the rate as a prediction about your agent.

What the pattern tier misses, per source

Each scenario is scored twice: once against its ground truth, and once with the regex tier alone. The gap between "no pattern matched" and "nothing leaked" is where a privacy score quietly stops being worth anything.

Built-in examples · 10 scenarios5 scored a perfect 100/100 without ground truth · 5 would not block a gate · 5 fail once it is attached
By pattern
AgentDojo · 100 scenarios7 scored a perfect 100/100 without ground truth · 45 would not block a gate · 100 fail once it is attached
By hijack
AgentLeak Bench · 36 scenarios0 scored a perfect 100/100 without ground truth · 13 would not block a gate · 23 fail once it is attached
By pattern
PrivacyLens · 120 scenarios62 scored a perfect 100/100 without ground truth · 67 would not block a gate · 119 fail once it is attached
By norm

Method, and what this is not

Every scenario bundled in the package, analyzed by the deterministic pipeline in fast mode (regex tier). Scenarios carrying ground-truth canaries are scored twice: once with them and once without, so the gap between 'no pattern matched' and 'nothing leaked' is measured. No model is called, so re-running this reproduces the numbers exactly.

Not a model rankingNo model is called. This measures detection against fixed traces, so it says nothing about which LLM leaks more. A model-by-model run needs API keys and is a separate exercise.
ReproducibleRun python scripts/build_benchmark.py against AgentLeak 0.16.0. Same inputs, same numbers.
Deterministic by designScoring uses exact ground-truth matching, not a judge model, which is what makes a regression in CI meaningful rather than noise.