The 15%-to-80% Gap Is Labeling Work, Not a Model Upgrade
Three independent teams converged on the same finding: what separates a demo from a feature users never disable is failure data and a second opinion, not a better base model.
What the interventions actually bought
A Figma engineer opens a pull request and gets back a finding that is actually correct. That is the whole product, and the model is not what made it correct. The system runs on one shared threat-model policy of 68 precedents across three surfaces. It guards code at generation time, reviews every pull request, and audits a decade-old monorepo. The precision climb came from failure data rather than prompt cleverness: eight weeks of real pull requests, with false positives hand-labeled into a corpus. An adjudicator second pass, a cheap reviewer stage that re-reads each finding before it reaches a human, added roughly 30% recall on top of that.
Two more results belong in the spec, and they are the two most often skipped. Running Claude Code and Codex in parallel produced a 75.8% union catch rate across 66 real vulnerabilities (46 from HackerOne, 20 from incidents and internal audits), because the two models miss different bug classes. Prevention also outperformed detection: agent hooks enforcing secure-by-default patterns at authoring time produced about 50% fewer logging safety bugs. The backfill sweep of the old monorepo turned up 100+ latent vulnerabilities, two of them critical, that traditional static analysis missed.
Where the evidence agrees, and where it splits
The sources agree on the negative claim. Nobody credits the base model for the improvement. They split on the cheapest first move. Stanford's work, summarized by DeepLearning.AI, found that ten models asked explicitly for secure code still shipped flaws in 20.1% of programs; the free-for-commercial-use SecureForge system prompt cut that to 11.8%, with GPT-5.4 going from 15.8% to 10.1%. Devshot reports auto-tuned instructions cutting cost about 32% while lifting task success by up to 21 percentage points. Read that as sequencing rather than a debate. The system prompt is days of work for a large relative gain. The labeled corpus is the asset that no vendor delivers.
The third component is who owns "done." What teams tell themselves is that a capable model with tools available will use them. What happened in a documented agent session is roughly two and a half hours, three context overflows and a mid-session model swap on a task that a properly specified instruction closed in 13 minutes. That instruction said install it, test end-to-end, name the edge cases, iterate until it passes. Tool availability is not tool invocation. Browser and computer-use tools sat unused until prompted, so the delivered artifact had never actually run.
A frontier model plus a good prompt is a 15% product. The 80% version is built out of labeled failures, a second-pass adjudicator, and two models disagreeing with each other.
The differentiator with the shortest shelf life
"AI suggests the fix" as a roadmap wedge deserves an honestly priced window. Google has shipped DeepMind's CodeMender into OSS-Fuzz, auto-generating compile-and-regression-validated patches, with automatic enrollment for existing projects. Verification is consolidating into a paid category of its own; Signadot's positioning is literally "AI writes code. Signadot makes sure it works." And be disciplined about claims: Anthropic's own Claude Mythos 5 documentation records cases where the model falsely stated it had verified code. The forcing function for the next planning cycle has two axes: does the feature generate the finding or adjudicate it, and does the labeled failure corpus belong to the team or to a vendor. The defensible cell is adjudication plus an owned corpus. "AI-verified" is a liability sentence wearing a feature bullet.
What to do
Add a 50+ case labeled eval set and a second-pass adjudicator to every AI-judgment feature in flight this sprint, with a named precision floor as the GA gate
Add a Verification Criteria block to the PRD and ticket template this sprint — executable done-criteria per task type, plus a plan-review gate before any agent is authorized to build
Ship the free optimized security system prompt plus a static-analysis gate on any surface that generates or executes code this quarter, then delete the word "verified" from product copy