Sigmastead

Private development · synthetic evidence only · Chester, Virginia

Two guarantees. One system.

A vault we cannot open. An AI that only says what your evidence supports.

Your records are encrypted on your device, under keys you control. Tech City holds no key that opens them. Guidance comes from the Evidence Engine, which computes facts in software, cites them to the evidence you chose, and states its limits.

Only a minimized packet you explicitly review and approve may be processed transiently for a requested analysis.

Explore the private alpha See how the guarantees work
Sigmastead Goal Studio · your goals Synthetic
Your goals
  • Protect two quiet evenings a weekTracking · no AI
  • Read for enjoyment, not completionTracking · no AI
  • Know where the month goesNot connected
  • Race without running myself down1 cited observation
  • One trip with the family this yearPrivate note
Selected · Protect two quiet evenings a week Track without suggestions Personal calendar · 8 weeks · no model request
Goal Momentum
2 of 4 milestones · you confirmed
Quiet evenings · last 8 weeks · your calendar, on your device
Nothing here has been sent anywhere. Add context, correct a week, or ask a question when you're ready.

Private by construction · honest by design

Two guarantees, working as one.

The Vault decides what can leave your device. The Evidence Engine is limited to the evidence you let through.

Guarantee 01 · The Vault

A vault we cannot open.

Records are encrypted on your device, under keys you control. Storage holds ciphertext. Tech City holds no key that opens it.

Sigmastead Exact packet · health example · review before consent Synthetic
Stays on this device
  • Raw exports
  • Names, free text
  • Calendar titles, attendees
  • Locations, device IDs
  • Vault keys
Would leave, once, after you approve
ev-3f9a training stress 450
ev-71c2 training stress 200
ev-b04e sleep hours 6.0
ev-d281 sleep hours 6.0
Purpose bound · region fixed · expires in 5:00
I approve exactly this packet, for this purpose, once.
  • Client-side encryption, ciphertext-only storage
  • Bounded sharing, with revocation
  • Encrypted export and recovery, verified deletion
Built · synthetic Independent review not yet complete.

Guarantee 02 · The Evidence Engine

An AI that only says what your evidence supports.

A deterministic engine computes the facts in software and cites them to your records. The model writes only bounded prose roles within reviewed limits, and validation rejects unsupported or out-of-bounds substitutions — so what you see is computed and cited, not generated. Proven for one goal type so far.

Sigmastead Cited observation · health example Synthetic
Observation · computed by software

Training stress fell from 450 to 200 (−250) between the weeks of 7 and 14 January, while average sleep stayed at 6.0 hours.

ev-3f9aev-71c2ev-b04eev-d281
Limits · bounded, validated prose
  • Two weeks can't establish a pattern
  • No calendar evidence in the window
  • No causal claim, either direction
Authority

Your coach owns the plan. Your clinician owns medical decisions. You own what happens next.

  • Facts computed by software and citations checked by software
  • The model writes only bounded prose within reviewed limits
  • Validation rejects unsupported or out-of-bounds content
Being validated One synthetic health scenario so far, on one model.

Where the two guarantees meet.

The Engine doesn't get your vault. It gets one packet you've reviewed, for one purpose, once.

Stays on your device
  • Raw exports
  • Names and free text
  • Calendar titles and attendees
  • Locations and device identifiers
  • Vault keys
May cross, once, after you review
  • The exact question
  • Opaque identifiers
  • Dates, metric names, units
  • Aggregate values
  • Exclusions and limitations
Returns
  • Structured observation
  • Citations
  • Uncertainty and limitations
  • One bounded next step
  • Authority boundary

Minimized is not anonymous, and we won't call it that · full trust model

The Evidence Engine follows an established pattern called neurosymbolic AI, which pairs deterministic computation with a language model. What's different is where it's applied: to personal data only you hold the keys to.

Goal Studio · where you use both

Your life is bigger than any one app.

Time, money, learning, health, family, work. Goal Studio is where the two guarantees become useful. Pick one goal, choose which evidence may inform it, and decide what happens next. What you add stays in your Vault. Any guidance comes from the Evidence Engine and is cited to the evidence you chose.

Sigmastead Goal Studio · your goals Synthetic
Your goals
  • Protect two quiet evenings a weekTracking · no AI
  • Read for enjoyment, not completionTracking · no AI
  • Know where the month goesNot connected
  • Race without running myself down1 cited observation
  • One trip with the family this yearPrivate note
Selected · Protect two quiet evenings a week Track without suggestions Personal calendar · 8 weeks · no model request
Goal Momentum
2 of 4 milestones · you confirmed
Quiet evenings · last 8 weeks · your calendar, on your device
Nothing here has been sent anywhere. Add context, correct a week, or ask a question when you're ready.

Every app knows a sliver.
Nothing knows the shape.

Your calendar knows the crowded weeks. Your bank knows what they cost. Your reading app knows what you finished. Your health data knows how you slept. None of them can see past its own edges.

Six separate life signals; three cross into one direction only after a visible choice Six parallel threads labeled health, time, learning, money, goal, and experience run left to right and never touch. At a dashed vertical line marked “you choose”, three threads (health, time, and goal) have been ticked; they bend toward a glowing mint Sigma junction and continue as one thicker direction line. The other three stop at the line with an open end, labeled “stays on your device.” health time learning money goal experience stays on your device you choose one chosen direction

Signals stay separate until you tick them for a goal · nothing crosses because a dataset happens to exist

Goal Studio · the first useful loop

Choose. Understand. Act.

Choose

Name one goal and select which evidence may inform it.

Vault · purpose before transfer

Understand

Review the evidence, limits, and source behind each observation.

Evidence Engine · cited, with limits

Act

Decide whether to try a bounded next step and track it without pressure.

Vault · milestones stay on device

The initial wedge is goal guidance from user-selected evidence—not a social network, marketplace, or medical service. For goals you own, you may choose Sigmastead as a coach; it never assumes that role or takes authority from a human coach or clinician.

Goal Studio · Choose

Your goal chooses the question.

Pick one purpose and confirm it. Available data never picks a goal for you. “Track without suggestions” and “not sure yet” make zero requests. Shown here for a health goal—the same choice screen governs any domain you connect.

Built · synthetic
Sigmastead Goal Studio · Read for enjoyment, not completion Synthetic

What kind of help do you want with this goal?

  • Prepare a focused question about what's getting in the way.
  • Track without suggestions. No model request.
  • Not sure yet. Pause until it's clearer.
Packet review and consent stay locked until you confirm a purpose.

Goal Studio · Act

Progress without manipulation.

Milestones you confirm. Reflection you choose. Pause without penalty. No streaks, no leaderboards, no rewards for handing over more data. Shown here for a personal-time goal—milestones and pacing work the same way for any goal you track.

Built locally · synthetic
Sigmastead Goal Momentum · Protect two quiet evenings a week Synthetic

Protect two quiet evenings a week

  • Move the Thursday standing callYou confirmed
  • Four weeks with two clear eveningsCited evidence
  • Tell the family which nights are off-limitsNot complete
  • Weekly reflectionOptional
Paused 2 weeks for travel. Nothing lost. No streak. No penalty.

Proof, not promises.

Working · synthetic

  • PlatformSign-in and private namespace
  • VaultClient-side encryption, ciphertext storage
  • VaultExact-object authorization
  • VaultBounded sharing and revocation
  • VaultEncrypted export and recovery
  • VaultVerified deletion for managed objects
  • EnginePacket preview, software-checked citations

Deliberately later

  • Invited alpha, pricing, support, legal review
  • Designed Portable credentials and a verified-person marketplace, built around cited Goal Momentum evidence—not a résumé, star rating, or unverified claim.
  • Controlled research licensing
  • User-published terms integrity
  • Creator, storefront, community

No customers · no revenue · no certifications · last reviewed 26 September 2026 · full ledger

Roadmap architecture · not launched

The future Sigmastead fabric.

Permission layers, earned from the inside out. Private vault data never silently becomes public, advertising, model-training, social, or marketplace data.

The “fabric” is the future permission layer that could let separate apps exchange only the data or claims a person approves. It is an architectural direction, not a product available today.

See the horizons

Four concentric permission layers around a unified Vault and Evidence Engine core A single mint core contains the customer-controlled Vault and the Evidence Engine as one system in synthetic development. Around it, a dashed amber ring labeled selective sharing, next. Then a dotted slate ring labeled portable credentials and verified-person marketplace, designed and in active M5 build. A second dotted slate ring is research licensing, designed and sequenced for M6. The outermost faint ring is creator, storefront, and community, directional design for M7. Vault / Evidence Engine Selective sharing NEXT Credentials · verified marketplace DESIGNED · ACTIVE BUILD / M5 Creator · storefront · community DIRECTIONAL DESIGN · M7 Research licensing DESIGNED · M6

Pick the door that fits.

Start with the matching overview. Email opens only after you see what to include—and what sensitive information not to send.

Tech City LLC · Chester, Virginia · veteran-owned · one mailbox, read by a person · about the company