codeLinc 11 · Path 1: Dental

Cusp

Use your benefits before they run out.

A dental benefits optimizer: what is covered, what you owe, when to book it.

The problem

The plan answers one question. The employee has another.

What the plan says (paraphrased)

Major services are payable at 50% of the Maximum Allowable Charge, after the Calendar Year Deductible, subject to the Alternate Benefit provision and the Annual Maximum.

What the employee needs answered

My dentist says I need a crown. What will I owe?

Four defined terms in the plan. Not one dollar figure for the person holding it.

What we built

Describe the care you need. We show what you will owe, and when to book it.

Core ask 1

Describe

Type the procedure. Add your plan as text, a PDF, or a photo.

For exampleA crown on my lower left molar.

Core ask 2

Translate

What is covered, what you owe, and the jargon in plain words.

For exampleThis plan pays 80% of a root canal, after your deductible.

Core ask 3

Sequence

Care ordered across the plan year to use the benefit well.

For exampleTwo procedures now, two after January 1.

The key design decision

Claude reads and explains. The engine does every dollar.

The most important design decision. Claude does two jobs here, both about language. Before the numbers, it reads your messy description and your plan and turns them into structured data; after the numbers, it explains the result in your language. In the middle, plain deterministic code computes every dollar: the deductible, your share, the annual max, in or out of network. Three principles hold it together. Deterministic core means the same inputs always give the same dollars, because the money is counted in whole cents with no rounding surprises. Schema-constrained output means Claude's answers must fit a strict template, and we check them again ourselves before using them. Grounded extraction means every plan term Claude pulls from a document comes with the page and the exact quote it came from, so we can check it.

Trust

Every number we read cites its source.

This is how we earn trust. When you upload your plan booklet, Claude pulls out terms like the annual maximum, and for each one it has to hand back the page number and the exact quote it relied on. Then our server checks that quote against the PDF's own text. Here the sentence on page 2 really says fifteen hundred dollars, so the field is marked verified. If a quote can't be found, the field is flagged needs-review and you confirm it yourself. That's the hallucination guard, in plain terms: no number goes unchecked against the document. On the right, the spend cap: the server tracks what the AI has cost and refuses further AI calls at a hard limit, while the cost engine keeps working. In our last live run, 48 of 49 fields were verified and the 49th was flagged for review, at a total of about twelve cents for four requests.

Computed by the Cusp engine

One root canal, $290 less in-network.

Root canal on tooth 26 (CDT D3330), Standard PPO 100/80/50: 80% in-network, 60% out, $50 deductible, $1,500 annual max. Dentist bills $1,200; in-network allowed $900 (25% network discount).

Care across the plan year · computed by the Cusp engine

The same four procedures cost $698.50 less when sequenced.

The three bonus asks

Track it, compare it, and be reminded before it is gone.

Bonus 1

Usage tracker

Annual max used and remaining, all year.

Bonus 2

Network compare

In-network against out-of-network, per procedure.

Bonus 3

Year-end reminders

A nudge about unused benefits before they expire.

Interactive 3D teeth

Tap a tooth, see what your plan does.

Selected · tooth 26

Upper left first molar

Planned: Root canal
Class: Basic, 80%
You owe: $220

Ten languages, read aloud

In your language, and out loud.

Englishen

Españoles

Françaisfr

Portuguêspt

简体中文zh

हिन्दीhi

العربيةar · rtl

Tiếng Việtvi

한국어ko

Русскийru

Architecture and safety

Keys and spend stay on the server.

Under the hood

Every claim, with the file that proves it.

Deterministic core

Money is integer cents; a fractional amount throws. packages/core

Schema-constrained output

Claude must return JSON that fits a schema; the server re-validates it with zod. apps/server/src/ai

Grounded extraction

Each field carries a page and quote, checked against the PDF’s own text. Last live run: 48 of 49 verified, 1 flagged. apps/server/src/evidence.ts

Verified optimizer

The planner’s results are compared with brute-force search in core’s tests. packages/core/test/sequence.test.ts

Defense in depth

Key stays on the server, user text is fenced as data, hard spend cap, uploads checked by magic bytes, tests grep for leaked secrets. apps/server/test/leaks.test.ts

Graceful degradation

If Claude fails or the cap is hit, the engine still answers; if Grok TTS fails, the device voice reads. apps/server/test/claude.test.ts

Real documents

PDF, photo, EOB or ID card; progress streams live; the same file is never read twice; per-IP rate limits. apps/server/test/upload.test.ts

Contract-first

One API contract and typed schemas, shared by the server and the app. apps/server/API.md

Tests passing: core 218 · server 217 · teeth3d 46. Managed, memory-safe stack (TypeScript, no manual memory).

This slide is the evidence table, one claim per row with the file to open. Deterministic core: the money math always gives the same answer, because it counts whole cents. Schema-constrained output: the AI has to answer in a fixed template, and we double-check the answer before using it. Grounded extraction: every number read from your plan carries the page and quote it came from, and we check the quote against the document. Verified optimizer: the care-sequencing planner is compared against trying every possible schedule, in our tests. Defense in depth: several independent protections, so one failing doesn't expose anything: the key stays on the server, your text is treated as data, spending has a hard cap, and uploads are checked by their actual bytes. Graceful degradation: if the AI is down or capped, the cost engine still answers, and if the premium voice fails, your device reads it aloud. Real documents: PDFs, photos, claim statements and ID cards, with live progress and no repeat charges for the same file. Contract-first: the server and app share one typed contract, so they can't drift apart. And the whole stack is TypeScript, a managed, memory-safe language.

Honest limits

What it is not, and what comes next.

Limits today

An estimate, not a claim decision. Your EOB has the final say.

Only as good as the plan terms and fees it is given.

Not medical advice. Your dentist decides the care.

Let's try it.

My dentist says I need a crown on my lower left molar.

1Add the plan2Read the breakdown3Tap the tooth4Switch language

Cusp · Use your benefits before they run out. · github.com/teddytennant/codelinc