California’s AI Permit Review Assistant

Spell Check for
Building Code.

CrossBeam reads ADU construction plans, cross-references California law and your city’s municipal code, and drafts corrections letters. Your staff reviews the output. Nothing goes out without a human.

ADU architectural miniature

1st Place — Built with Claude Code Hackathon 2026 · 13,000 applicants, 500 accepted

California Has a Permit Crisis

The state has passed 25+ ADU bills since 2016. Cities want to comply. But they literally don’t have enough staff to process the volume.

429,503

ADU permits in CA since 2018

Shovels.ai

90%+

sent back for corrections in San Jose

Mercury News

35,800

fewer local gov workers since 2020

UC Berkeley Labor Center

$30,000

cost of a 6-month permit delay

Lost rent + inflation + loan carry

Both sides lose. Cities are drowning in applications with county vacancy rates up to 30%. Builders wait months and eat $30K in carrying costs. The routine 60% of plan check — stamps present? codes listed? fire rating correct? — is the same work, repeated thousands of times.

For Cities

Your plan checkers focus on judgment.
AI handles the routine 60%.

Plans go in. AI drafts a corrections letter citing state and city code. Your staff reviews, edits, and sends. Think of it as spell check for building code — it catches the missing stamps, absent citations, and overlooked code sections so your reviewers focus on the engineering judgment that actually requires their expertise.

The Correction Tax

Your building department pays third-party consultants $150–$175/hr to review plans. When plans come back with corrections — and 60–90% do — the consultant re-reviews at the same hourly rate. But the homeowner’s original fee already covered the first review.

Every included correction cycle is a pure cost to the city. $300–$625 per round, recovered $0 from the applicant.

Source: Public consultant contracts — CSG, WC3, Bureau Veritas hourly rates from Huntington Beach, South San Francisco, Alameda city council records

The Misaligned Incentive

Third-party plan review consultants bill hourly. Every correction cycle is more revenue for them. A sloppy submittal that requires 3 rounds of review is more profitable than a clean one approved in 1 round.

No consultant is going to build a tool that reduces their own billable hours.

CSG, WC3, and Bureau Veritas serve the majority of California cities on hourly contracts

What You Get

Draft corrections letter

Code-cited, item-by-item, ready for staff review. References CRC, CPC, CBC, Title 24, and your city’s municipal code.

Code research report

State law + your city’s ADU ordinance cross-referenced. AI researches your city’s specific requirements via web search across 480+ city websites.

Compliance checklist

Every applicable code section verified against the submitted plans. Catches the routine items — stamps, signatures, fire ratings, setback dimensions — before your reviewer opens the file.

Human-in-the-loop, always

Nothing goes out without your staff’s sign-off. AI drafts, humans approve. Your department stays in the driver’s seat.

The ROI

Modeled on a mid-size CA city (~80K population, ~500 building permits/year, 4–5 building staff)

Direct savings on correction re-reviews$80K/yr
Plan checker hours freed500 hrs/yr
Additional permit throughput+25%
Unlocked permit fee revenue$250K/yr

CrossBeam: $12–18K/yr

vs. hiring 3 plan checkers at $336–408K/yr

18–34x cheaper

Based on public consultant contracts, CALBO staffing data, and Buena Park/Huntington Beach budget records

“AI in permitting will rebuild faster and safer, reducing costs and turning a process that can take weeks and months into one that can happen in hours or days.”

— Governor Gavin Newsom, April 2025

On launching AI tools for LA fire recovery permitting · Governor’s Office press release

For Builders

Got a corrections letter?
AI reads it, drafts your response.

A 14-item corrections letter from the city. Each item cites a different code section — CRC, CPC, CBC, ASCE 7-16, Title 24. Your engineer takes days to parse each one, pull the relevant code, cross-reference the plans, and write a professional response. CrossBeam does it in 15 minutes.

Corrections Analysis

Each correction item categorized: auto-fixable, needs contractor input, or needs a professional engineer. Code references verified against state and city law.

Response Letter

Professional tone. Item-by-item responses with sheet references and code citations. Technical justifications for sewer capacity, wind loads, drainage slopes. Ready for resubmission.

Code Research

Every cited code section pulled and cross-referenced. State law, your city’s municipal code, and standard details — all in one place instead of scattered across 6 different websites.

15 min

14-item corrections letter analyzed

~$3

per review in AI costs

480+

California cities’ codes researched

“Keeping up with building code changes is its own full-time job for builders.”

— CalMatters, 2025

How It Works

Four steps. Human always reviews before anything goes out.

1

Upload Plans

Drag and drop construction plans or a corrections letter. PDF, any size.

2

AI Reviews

CrossBeam reads every page and cross-references California law + your city's municipal code.

3

Draft Generated

A corrections letter (or response letter) is drafted with code citations and sheet references.

4

Human Reviews

Your staff reviews, edits, and approves. Nothing goes out without a human sign-off.

See It in Action

Full corrections analysis on a real Placentia ADU permit — 14 items parsed, verified, and responded to.

Try It Right Now

Ask the chatbot anything about California ADU law — setbacks, height limits, parking, fire sprinklers, owner occupancy. It knows 480+ cities and 28 files of state code.

1st Place

Built with Claude Code Hackathon 2026. 13,000 applicants, 500 accepted.

Piloting with Cities

Currently piloting with California cities for ADU permit review.

$250M+ in VC

Deployed to permit tech companies. The market is validated.

Claude Opus 4.6

Anthropic’s most capable model + Agent SDK. Human-in-the-loop by design.