Celestial Sphere is a five-phase agentic development lifecycle — a structured way to take a build request from raw intent to verified, shipped code. Every phase has one job, one input, and one artifact it hands forward.
Most AI-assisted development is one long conversation that slowly loses the thread. Celestial Sphere replaces the conversation with a cycle: five agents, each with a defined domain, each producing a real artifact the next one builds on.
Requirements before design. Design before architecture. Architecture before code. And nothing ships until it has been read back against what was actually asked for.
The cycle does not end at deployment — it begins again, informed by reality.
Each phase maps to a distinct domain of product development, takes in a defined artifact, and produces a defined output that feeds the next.
The observatory. Before anything is designed or built, this phase gathers everything there is to know about the problem space and synthesizes it into a single understanding of what needs to exist, and why.
Translates requirements into human experience. Where Stellarium defines what the product must do, Oracle defines how a person encounters it — what they see, read, and understand. Copy is treated as core UX, not decoration.
The calculation engine. Turns requirements and design into an exact technical blueprint — data models, the full API contract, computational flows, the security model. Designed against the codebase that actually exists, not a greenfield ideal.
Builds the thing. Wireframes become components, flows become routes, infrastructure decisions become deployed services. Where the spec is ambiguous, Accretion surfaces it rather than making a silent decision that diverges from intent.
The quality gate, and it runs before anything reaches a pull request. Witness runs the toolchain itself — typecheck, build, lint — trusting no claim that it already passed, then reads the diff against the spec. It returns a verdict, not a report.
Every cycle is initiated with a work type, so a one-line bug fix doesn’t trigger a full app re-scaffold. The type narrows scope — it never relaxes rigor.
Celestial Sphere is the method behind the show. Each working session is the cycle running on a real product, with the decisions left in.
For four episodes, the Celestial Sphere kept rebuilding the shell instead of building features. This is the episode where we found out why.
Rachel and Céleste pull the threads from the guardrails working session: why scope isn't always scope creep, and why Witness — the QA agent — turned out to be a phantom.
The second working session — the UI comes to life, and the first feature begins.
The first working session — building in public, thinking out loud.
The lifecycle is open — read it, take it, run it yourself. The orchestrator that drives it is in use on live products and is not publicly available yet.