ViewSpec is an agent-native app compiler. Agents emit IntentBundle or AppBundle JSON, and ViewSpec validates it, applies DESIGN.md, records provenance, compiles renderer outputs, generates bounded reducers, and writes proof reports.

Does ViewSpec call an LLM at runtime?

No. The local compiler and generated artifacts are deterministic and do not call a runtime LLM.

ViewSpec Studio - Build with your agent, then point at what changes

/ ViewSpec Studio · local beta

One room from first brief to final approval.

The interface, its behavior, and your feedback stay connected. You can see what the agent built, compare both delivery targets, inspect declared state and fixture data, and point at the exact result that should change.

Field dispatch· revision 7

checked · local only

Same source · synchronized route

3907681440

Static · checked

Field dispatch

Open incidents · west region

J-205 · Signal faultRoute crew within 20 minutesurgent

J-207 · Pump alertResource: crew-12queued

/dispatch/incidents

React · checked

Field dispatch

Open incidents · west region

J-205 · Signal faultRoute crew within 20 minutesurgent

J-207 · Pump alertResource: crew-12investigating

/dispatch/incidents

01CreateBind the brief and reference.

02CompareStatic and React, side by side.

03InspectReplay behavior and fixture data.

04DecideComment precisely, then approve.

viewspec studio --brief-file product-brief.md --reference reference.png --kind app --jsonviewspec studio viewspec.app.json --compare --install

What is proven today: local creation, checked static and React builds, synchronized routes and semantic identity, declared-state replay, fixture-resource inspection, source-bound feedback, and approval. The private-review transport contract completes the exact comment-to-approval journey locally in Chromium, Firefox, and WebKit; no hosted review endpoint is deployed. Static/React visual parity is not claimed. Production data is not loaded.

/ the model

Agents shouldn’t write markup. They should commit to meaning.

An IntentBundle is a semantic contract, not a template. The compiler turns it into an interface the same way every time — and can prove what it did.

Deterministic

Same intent, same bytes, same hash — on every machine, every run. No model in the render path, so output never drifts.

Portable

One bundle emits html‑tailwind and React locally; the paid API delivers four targets with hashes, provenance, and diagnostics.

Provable

Every element carries its lineage. Trace any pixel to the binding and raw data — and prove the artifact phones home to nobody.

/ one intent, every shape

The data doesn’t change. The motif does.

An agent describes a group of things. You decide whether it’s a table, a dashboard, or a gallery. Flip it — same four bindings, three renderings.

group: capabilities · motif: table · ordered 4 bindings · exactly‑once

/ style derivation

Style is a token, not a task.

Pick an aesthetic profile. The compiler re‑derives density, emphasis, rhythm, and grid from a single token — a lookup, not a redesign. This whole page re‑themes with it.

density regular · emphasis medium · columns 3

aesthetic.calm_ops · 0 hand‑written rules · Same graph, new projection from the same semantic graph

/ now look under the hood

Everything above is compiled output. Here’s the receipt.

Turn on Inspect (top‑right, or press i) and every element on the page shows the IR address it came from. Click, tap, or hover a chip below to trace one all the way back to the data.

compiled artifact · real IR ids · click/tap/hover a node

intent_bundle.json provenance_manifest.json profile-evidence.json

compiled artifact · aesthetic.calm_ops · scroll & hover

replay

state replay passed

reducer

reducer generated

manifest

manifest checked

shell

shell hash matched

runtime

No runtime LLM

browser corpus

10/10 conformant

viewports

mobile · tablet · desktop

product quality

10/10 first-compile passes · 0 critical issues

semantic corrections

10/10 verified previews · 10 applied receipts

refinement gates

8/8 passed

1 · intent

Agent writes IntentBundle JSON.

2 · compile

CompositionIR to UI and reducer, no LLM.

3 · proof

Provenance, replay, and shell hash attached.

State IR	interactive_state_v0 writes state_reducer.ts and reduceViewSpecState.
Aesthetic Profiles	Eight compiled projections from one semantic graph.
Proof Pipeline	state_replay_assertions plus viewspec prove-app --with-shell.
Semantic Correction	Source-bound previews and applied receipts keep changes traceable.
Portable Surfaces	html-tailwind and React locally; four integrity-checked targets through the paid API.

describe	Author IntentBundle or AppBundle JSON.
validate	viewspec validate-intent fails closed on drift.
prove	viewspec prove --intent compiles, checks, and renders the exact artifact.

Free	Local SDK. Unlimited compiles, proofs, and surfaces.
Pro	149/mo. Hosted compiler API, 10k calls per day.
Enterprise	Custom volume, organization sharing, and support.

provenance

Every element traces to its address.

determinism

Same source, design, and compiler version; same bytes and hash.

the entire homepage artifact, embedded live · open it full-page ↗

DOM → binding → address → data

/ trust, but verify

Then verify again, and get the same answer.

Two claims most tools ask you to take on faith. Here they’re computed on the page you’re reading.

Deterministic provenance

The provenance hash is sha256 over the canonical IntentBundle. Recompute it — identical bytes, identical digest, every time.

sha256 = computing…

match — deterministic

Provably no‑network

ViewSpec’s check gate certifies an artifact makes zero cross‑origin requests before it ships. This page holds itself to the same bar — measured live:

0cross‑origin requests

Checked core workflow · 10/10 conformant

All 10 fixed cases passed product quality on first compile with 0 critical issues, rendered at mobile, tablet, and desktop with accessibility, DOM, log, and screenshot evidence, and completed 10/10 verified semantic corrections with 10 applied receipts. Explore the retained evidence · Eight-gate result · Scorecard · Correction proof. Fixed-corpus evidence is not certification of arbitrary briefs or host apps.

/ exact-versioned proof integrations

Freerange and Pretext, end-to-end accountable.

Two opt-in integrations by chenglou bind declared source inventories to independently checked generated behavior in react-tailwind-app proofs.

Freerange numeric proof

@chenglou/freerange@0.0.1 binds every eligible state-operation occurrence to the emitted state contract, exact generated helpers, 100% function analysis, and runtime call sites.

viewspec prove-app --app viewspec.app.json --target react-tailwind-app --install --freerange --json

Requires a user-installed stable Bun 1.x on PATH. ViewSpec never installs Bun.

It does not analyze CSS, prove rendered geometry, certify arbitrary math, or certify arbitrary host apps.

Pretext text proof

@chenglou/pretext@0.0.8 preserves native DOM semantics, independently inventories every eligible text surface per route and viewport, and checks native-DOM versus Pretext line count and overflow with named Arial, sans-serif.

viewspec prove-app --app viewspec.app.json --target react-tailwind-app --install --pretext --json

Runs at 390×844, 768×1024, and 1440×1000 in Chromium. No Bun required.

It is not general typography proof, canvas-rendering proof, pixel-perfect visual regression, accessibility certification, or arbitrary-host certification.

Compose the proofs: viewspec prove-app --app viewspec.app.json --target react-tailwind-app --install --freerange --pretext --json runs both independently reported analyses and does not broaden either guarantee. Dedicated hosted E2E is configured to cover healthy proofs plus division, bounds, font, wrapping, and overflow mutation rejection on relevant changes, weekly, and by manual dispatch; this does not claim that a hosted run has completed.

Tell your agent what to build.
See the real product.
Point at what should change.

One room from first brief to final approval.

Field dispatch

Field dispatch

Agents shouldn’t write markup. They should commit to meaning.

Deterministic

Portable

Provable

The data doesn’t change. The motif does.

Style is a token, not a task.

Everything above is compiled output. Here’s the receipt.

Tell your agent what to build. See the real product.

Then verify again, and get the same answer.

Checked core workflow · 10/10 conformant

Freerange and Pretext, end-to-end accountable.

Start local. Add the hosted compiler when teams need it.

Free local SDK

Pro hosted compiler

Enterprise support

Compile your first interface in a minute.