@Scale
Meta is deploying AI agents to triage traffic anomalies, fix data inconsistencies, and log human decision traces so network capacity planning continuously improves from past outcomes rather than relying on static long-range forecasts.
AI-assisted summary of Live from the SCCC: The Plan That Learns | Ben Vallis, Meta — original source. Check the original for full context.
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Detailed notes
## Background Published on YouTube by @Scale on August 31, 2026, this page features Meta's Ben Vallis delivering a lightning talk titled "The Plan That Learns" at the Santa Clara Convention Center. According to the page description, the presentation focuses on applying AI agents to high-stakes network capacity planning decisions—specifically acting inside narrow buy windows, standardizing data across systems, and generating costed menus of timing-sensitive levers.
## TL;DR Ben Vallis argues that network capacity planning is inherently asymmetrical, where underforecasting creates catastrophic platform bottlenecks while overforecasting is relatively benign. To avoid getting cornered by unforecastable black swan events and correlated demand surges, Meta uses AI agents across three key operational pillars: triaging hundreds of noisy telemetry anomalies down to actionable signals, elevating data accuracy past 80% through an evaluation and enrichment loop, and modeling complex hardware and software mitigation levers in hours rather than months. Ultimately, the system captures human overrides as structured decision traces, allowing institutional judgment to compound over multi-year horizons into a continuously learning feedback loop.
## Atmosphere & style The presentation carries the pragmatic, grounded tone of an experienced systems engineer confronting the unpredictable nature of massive-scale infrastructure. Vallis speaks with candid humility about the certainty of being wrong, blending strategic chess analogies with high-stakes operational realities. The dynamic feels authoritative yet accessible, channeling an analytical focus that transforms complex network trade-offs into an engaging discussion on AI-driven resilience.
## Key takeaways - [00:04](https://www.youtube.com/watch?v=3IteDwOdNyk&t=4s) Capacity planners must commit network resources years in advance while accepting that long-range demand forecasts are guaranteed to be wrong. - [00:04](https://www.youtube.com/watch?v=3IteDwOdNyk&t=4s) Forecast errors are asymmetrical in tech infrastructure: overbuilding capacity is a minor issue, but underforecasting bottlenecks the entire service platform. - [00:04](https://www.youtube.com/watch?v=3IteDwOdNyk&t=4s) Massive upside demand shocks are driven by spontaneous concurrency events (e.g., global news like the Queen's passing) rather than predictable calendar events like New Year's Eve. - [00:04](https://www.youtube.com/watch?v=3IteDwOdNyk&t=4s) The core strategy of modern network planning is positioning capacity to withstand a wide range of forecast failures without getting backed into a corner. - [03:40](https://www.youtube.com/watch?v=3IteDwOdNyk&t=220s) Real-world supply chain constraints prevent companies from simply over-provisioning hardware to match maximum demand estimates. - [03:40](https://www.youtube.com/watch?v=3IteDwOdNyk&t=220s) AI agents reduce signal triage time from weeks down to minutes by correlating telemetry, parsing news, and traversing codebases to isolate true anomalies. - [03:40](https://www.youtube.com/watch?v=3IteDwOdNyk&t=220s) Improving AI data trustability from 30% to over 80% requires an iterative measure-enrich-regrade loop and single sources of truth. - [03:40](https://www.youtube.com/watch?v=3IteDwOdNyk&t=220s) AI compresses the evaluation of costed hardware and software mitigation levers from months down to hours. - [08:06](https://www.youtube.com/watch?v=3IteDwOdNyk&t=486s) Human engineering overrides of AI recommendations are treated as valuable unencoded judgment rather than compliance errors. - [08:06](https://www.youtube.com/watch?v=3IteDwOdNyk&t=486s) Structured decision traces log human reasoning alongside downstream outcomes to build an empirical memory of long-term trade-offs. - [08:06](https://www.youtube.com/watch?v=3IteDwOdNyk&t=486s) Capturing decision histories transforms capacity planning into a self-improving system where institutional knowledge compounds over time.
## Detailed walkthrough ### [00:04](https://www.youtube.com/watch?v=3IteDwOdNyk&t=4s) The Asymmetry of Capacity Planning and Surprises
Ben Vallis opens his talk by sharing a fundamental reality of his job: waking up every single morning knowing he is guaranteed to be wrong. As someone who has spent the better part of a decade positioning network infrastructure at Meta against unexpected surges, he views this continuous uncertainty as an unavoidable occupational hazard. Capacity planners must commit resources and make decisions today to intercept demand levels and unforeseen events years into the future. Over time, he has grown comfortable with this constant margin of error by coming to appreciate the profound asymmetry hidden within forecast graphs—while demand curves look symmetrical, the real-world consequences are anything but.
Tracing a line on the upside of a forecast and overbuilding capacity is a relatively harmless mistake in a high-growth technology business; it simply means the infrastructure was deployed a bit early. However, the inverse scenario is catastrophic: underforecasting demand leaves the network underbuilt, creating severe bottlenecks across the entire business. Consequently, planning teams are intensely sensitive to upside demand shocks. These upside spikes are driven by concurrency—tens or hundreds of millions of users hopping online simultaneously to perform the exact same action. While predictable calendar events like New Year's Eve can be planned for, true black swan events, such as the global reaction to the passing of Queen Elizabeth II across the UK, Canada, and Australia, create massive, un-forecastable traffic spikes. Realizing that predicting geopolitical events is a "fool's errand," Vallis flipped the core problem on its head: rather than chasing impossible forecasting accuracy, the real challenge is positioning network capacity so robustly that it covers the largest possible range of wrongness without ever getting backed into a corner or sacrificing user quality.
- **Consequences of Misestimate**: Overforecasting leads to early capacity (low impact in high-growth environments); underforecasting bottlenecks the entire service platform. - **Concurrency Drivers**: Spontaneous mega-events (e.g., global news like the Queen's passing) versus predictable spikes (e.g., New Year's Eve messaging/video calls). - **Core Philosophy**: Avoid getting "cornered" in a chess-like capacity game; design systems to remain robust against the widest spectrum of forecast failures.
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[03:40](https://www.youtube.com/watch?v=3IteDwOdNyk&t=220s) Three AI Levers: Acting in Time, Fixing Data, and Augmenting Decisions
Addressing a common counter-proposal—simply buying maximum hardware to match the top line of the uncertainty cone—Vallis notes that real-world supply chain constraints make it impossible to get precisely what is needed, where it is needed, or when it is needed. Capacity management is fundamentally a constrained optimization problem. To navigate this, Meta relies on AI across three core functional areas: acting in time, addressing unglamorous data foundations, and augmenting human engineering judgment.
First, AI enables teams to act within critical time windows. Meta's network observes hundreds of novel traffic anomalies weekly, ranging from benign cat video virality and routine codebase updates to internet routing shifts or random noise. Historically, manually triaging each dot on the metric graph to determine root cause and distinguish structural shifts from ephemeral noise took engineers weeks or months, often causing them to miss key action windows. AI agents excel at traversing massive codebases, cross-referencing global news, and correlating disparate telemetry, successfully whittling down hundreds of noisy signals into a manageable shortlist of actionable events. Second, AI acts as a forcing function to fix broken data foundations. Initially, asking different models basic questions like "how much capacity do I have?" yielded three conflicting answers depending on prompt phrasing or time of day. To eliminate these shaky foundations, Meta established a standardized evaluation suite. Early accuracy hovered around 30% ($\pm$ a few hundred basis points across models). Through an iterative "measure-enrich-regrade" loop—adding context, clarifying definitions, and establishing single sources of truth—they rapidly boosted model trustability past 80%. Third, AI dramatically accelerates decision-making when selecting from complex mitigation levers (e.g., pulling supply from warehouses, rerouting hardware in transit, shaping demand via software, or relaxing SLOs), compressing analysis time from weeks or months down to hours.
| Problem Area | Manual / Baseline State | AI-Enabled State | Key Mechanism / Strategy | |:--- |:--- |:--- |:--- | | **Signal Triaging** | Weeks to months to isolate root causes of weekly traffic anomalies. | Minutes to hours; surfaces a manageable shortlist of true signals. | Agentic code traversal, news parsing, and cross-system metric correlation. | | **Data Trustability** | Conflicting answers to basic queries; ~30% accuracy on standard eval suites. | 80%+ accuracy and rising. | Iterative enrichment, context mapping, and enforcing single sources of truth. | | **Action Selection** | Weeks/months to model cost, risk, and benefit of network levers. | Compressed to hours with high precision. | Automated costed/ranked menu generation across hardware and software levers. |
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[08:06](https://www.youtube.com/watch?v=3IteDwOdNyk&t=486s) The Plan That Learns: Decision Traces and Compounding Judgment
While generating automated menus of network actions is a major milestone, Vallis emphasizes that the real frontier is moving from a good system to a great system through "The Plan That Learns." In daily operations, human engineers often deviate from model recommendations when choosing the next network move. Rather than seeing this variance as a flaw or compliance issue, Vallis views human deviation as a valuable "gift" representing unencoded judgment—decades of institutional knowledge and intuitive trade-offs that engineers apply on the fly.
Historically, this human reasoning was discarded or buried in unorganized documentation after a decision was executed. To capture it, Meta is implementing structured "decision traces." This framework logs every operational decision alongside its underlying reasoning and tracks the actual downstream outcome over subsequent months and years. By analyzing these decision traces at scale across counterfactuals and repeated scenarios, the platform builds an empirical memory. Future recommendation engines can then explicitly inform planners: "70% of the time when a similar situation occurred, Option B yielded the optimal outcome." By capturing unencoded human intuition and measuring long-term results, capacity planning transforms into a continuously learning system where engineering judgment compounds over time instead of resetting with every new planner.
- **Unencoded Judgment**: Human overrides of AI recommendations are captured as high-value training inputs rather than errors. - **Decision Traces**: Historical choices are linked to real-world outcomes over multi-year horizons to systematically evaluate past trade-offs. - **Long-term Vision**: Network capacity decisions transition from static static forecasts to a dynamic, self-improving feedback loop.
## Notable quotes > [00:00](https://www.youtube.com/watch?v=3IteDwOdNyk&t=0s) The Plan That Learns — Ben Vallis
> capacity is committed years ahead, every long-range forecast is guaranteed to be wrong, and the costliest surprises are correlated demand shocks that defeat traditional risk-pooling.
> not to chase a more accurate forecast, but to position capacity so it keeps our options open no matter how demand breaks.
> acting inside narrow buy windows (triaging signals continuously to surface the handful of truly novel sites, weeks down to minutes), trusting data across systems that disagree on even basic definitions (a measure-enrich-regrade loop), and choosing among coupled, timing-sensitive levers (a ranked, costed menu of moves with the reasoning attached).
> agents that remember every decision and how it turned out, so human judgment compounds over time instead of resetting with each planner.
> [03:40](https://www.youtube.com/watch?v=3IteDwOdNyk&t=220s) how much capacity do I have? — Ben Vallis
> [08:06](https://www.youtube.com/watch?v=3IteDwOdNyk&t=486s) 70% of the time when a similar situation occurred, Option B yielded the optimal outcome. — Ben Vallis
## Mentioned Ben Vallis, Meta, Santa Clara Convention Center, @Scale, YouTube, Queen Elizabeth II, UK, Canada, Australia
[Source](https://www.youtube.com/watch?v=3IteDwOdNyk)