Ssylphx.ai
Models

The four models

One engine, four selection policies. Every Lumen tier reads the same request, scores the same internal lanes, and picks a seat — what you choose is how far it will spend for quality.

One engine. Four points on the curve.

Same router, same lanes, same learning ledger, on every tier — a tier is a selection policy over that identical, already-scored slate. Read left to right: cost-optimized to quality-ceiling. On an easy request all four may still pick the same lane, and that's the design working.

  1. 1

    Lumen Flash

    Cheapest lane that clears the bar. Maximum thrift.

    sylphx/lumen-flash
    Built forInteractive apps, chat surfaces, high-volume light work
    Selection policyTakes the cheapest lane that clears the quality bar, accepting a wide band below the predicted best.
    Escalation speedUpgrades its driving lane after four straight signs of session distress — the stickiest tier in the family, because thrift is what you bought.
  2. 2

    Lumen

    Default

    The default. Best value in the family.

    sylphx/lumen
    Built forEveryday agentic work
    Selection policyTakes the cheapest lane near the predicted best, with a tight tolerance.
    Escalation speedUpgrades its driving lane after three signs of distress.
  3. 3

    Lumen Pro

    The predicted best. You pay for the ceiling.

    sylphx/lumen-pro
    Built forComplex agentic work, planning, hard reasoning
    Selection policyTakes the predicted-best lane; cost only breaks near-ties.
    Escalation speedUpgrades its driving lane after two signs of distress — recovers from tool failures faster than Standard or Flash.
  4. 4

    Lumen Ultra

    Council on demand

    Zero tolerance — plus a council when it's hard.

    sylphx/lumen-ultra
    Built forResearch, critique, the decisions that matter
    Selection policyTakes the predicted best with zero tolerance. When a request looks hard or unfamiliar, it convenes a multi-lane council and an independent judge picks the served answer.
    Escalation speedUpgrades its driving lane after a single sign of distress — the fastest reaction in the family.

Choosing a tier

Full capability — vision, tools, streaming, English and 中文 — is on every tier. You are choosing a quality ceiling, not a feature set.

  • Latency-sensitive UI or bulk light tasksLumen Flash
  • Not sure which tier you needLumen
  • Your agent plans, architects, or reasons hardLumen Pro
  • The answer is worth waiting for when it's hardLumen Ultra

Certified, not claimed

Tier order isn't asserted once and left alone — it's checked continuously against production evidence.

Flash ≤ Standard ≤ Pro ≤ Ultra in judged quality is verified from real duels on live traffic, every day. If two neighbors ever stop separating beyond noise, they merge — four is a hypothesis the data has to keep earning, not doctrine.

See the full certification ladder and daily trajectory