BUILD STORY · 05 AUGUST 2026
Building an agent that knows when evidence is missing.
Hackathon rules are prose. Submission evidence is scattered across repositories, deployments, and demos. ProofFlow turns both into a source-cited ledger while keeping the model inside a deliberately narrow reasoning role.
A polished demo can still miss a mandatory disclosure, an eligible track, or the exact evidence a judge needs. The hard part is not summarizing a rules page. It is preserving the line between what a source proves and what a model merely finds plausible.
Six bounded stages
Lock the rules
ProofFlow accepts an official public rules page, validates the destination, removes URL fragments, and fingerprints the retrieved content so every audit names its binding source.
Extract obligations
Gemini 3.6 Flash receives bounded source material and returns schema-constrained requirements. The orchestration uses an 18-second request limit, disables automatic retries, and permits one Gemini 3.5 Flash Lite availability fallback.
Verify artifacts
Server-side checks inspect the submitted public GitHub repository and live deployment. Deterministic fetches establish what exists before model reasoning maps evidence to each requirement.
Choose the handoff
Gemma 4 receives only the validated risk and action lists, then must call one bounded function with an existing action index. An invalid or unavailable response falls back to the first validated action without weakening the audit.
Measure the grounding
Gemini Embedding 2 maps the selected action and up to five validated risks into a shared 128-dimensional space. ProofFlow records the closest risk and cosine score without allowing the optional check to rewrite the audit.
Persist the ledger
The final score, requirement findings, risks, selected operational priority, semantic-grounding result, source fingerprints, and model provenance are stored in private-by-default Firestore and rendered as JSON or a portable Markdown report.
What the agent refuses to blur
The audit reads the official rules URL, a public GitHub repository, and a public deployment. Credentials are never sent to Gemini or the browser.
Every requirement is marked verified, partial, or missing. The model cannot convert an absent artifact into a passing finding.
ProofFlow recommends the next concrete action but does not write to the audited repository or silently change a submission.
“The most useful agent is not the one that sounds certain. It is the one that can show exactly why it is certain—and stop where the evidence stops.”