Stop policing prompts: the harness, not the model, is the real security boundary
Agent security cannot be achieved by prompt-injection filters or instruction hardening; it must move to the harness layer by scoping credentials and side effects so that secret-bearing content is never model-visible.
AngleA postmortem of MoltBook that extracts reusable harness-design rules for API keys, database access, and tool-mediated side-effect containment.
Source video ↗More agents, less outcome: multi-agent systems have an Amdahl wall
Adding specialized subagents does not reliably improve a product; it often reduces reliability and increases latency because serial coordination overhead grows with agent count, so teams should estimate their task graph's serial fraction before choosing a single-agent versus swarm architecture.
AngleAn engineering cost model drawing on Google's scaling research and task-dependency reasoning.
Source video ↗Your simulated user is a stereotype: persona prompts contaminate social research
Persona prompting is a strong modeling prior, not neutral access to a simulated user; it can skew aggregate responses, for example pushing political simulations left, so researchers must run persona-free baselines and adversarial persona sets before drawing conclusions.
AngleA methodological critique and minimal validation protocol for using LLMs as simulated survey respondents or user proxies.
Source video ↗CanaryCredentialHarness
gatehouseAn agent harness that resolves all secrets inside infrastructure mediators and exposes only scoped, expiring capabilities to tools will have a significantly lower credential-leakage rate under adversarial prompt injection than an equivalent harness whose secrets are placed in prompts or agent environment variables, with no more than a small drop in task success.
Proof of conceptImplement a minimal email/database agent in two variants: a baseline where Supabase credentials and API keys are visible in the prompt or environment, and an experimental variant where credentials stay in a mediator process and tools receive scoped, expiring grants. Run the same set of prompt-injection and jailbreak attempts against both variants using canary secrets.
MeasurementLeakage rate (percentage of attacks that cause a canary secret to appear in output), task success rate on legitimate requests, and time-to-first-leak across the two setups.
Source video ↗AgentScalingAmdahl
newFor a fixed multi-tool task suite, latency per completed task is minimized at a small agent count (2–4) and rises monotonically for larger counts when the task graph's serial fraction is high; the serial fraction estimated from dependency traces will predict the observed optimum better than raw agent count.
Proof of conceptBuild an orchestrator that decomposes a common dev/QA-style benchmark into subtasks with known dependency matrices, then run teams of 1, 2, 4, 8, and 16 specialized agents using the same LLM backbone while recording traces of messages, waiting time, and task completion.
MeasurementWall-clock latency per completed task, success rate, coordination-message count per task, and R² of an Amdahl-like model compared against agent-count-only predictions.
Source video ↗PersonaPriorProbe
beyond-evalsChanging a demographic or political persona string shifts simulated survey responses by a larger distance than repeated sampling variance under the same persona, and the shift direction tracks stereotypic priors rather than realistic heterogeneity.
Proof of conceptSelect 20 polling-style statements; generate 1,000 synthetic responses per condition using persona-free, left-leaning, right-leaning, and demographic persona prompts. Vary temperature and random seed across 5 runs per condition.
MeasurementCohen's d between each persona condition and the persona-free baseline, within-condition dispersion across seeds, and the proportion of statements whose majority direction flips across conditions.
Source video ↗EffectSizeCalibrator
beyond-evalsAdding a stochastic human-behavior layer—abandonment probability, friction delays, and cost salience—to LLM shopping agents reduces the 10–30x effect-size inflation to within 2x of human A/B results while preserving the direction of the effect.
Proof of conceptTake a set of product changes with known human A/B effect sizes; run LLM shopping agents on each change in a raw condition and in a calibrated condition with a friction/abandonment model. Compare effect sizes against the human benchmarks.
MeasurementRatio of agent effect size to human effect size before and after calibration, sign-match rate, and calibration error across different funnel stages.
Source video ↗