System One Coding

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Open Code and choose Open editable sample · no AI request. Edit application.mith, explicitly compile and review the static artifact. To generate with your agent, sign in, select a report, dashboard or directory prompt, review the draft and send it. The completed coding tool opens the shared Desktop source editor.

Use Save to GitHub to connect your repository-scoped GitHub token, select a repository, review and save, then explicitly confirm Pages publication. Mithril sign-in does not grant GitHub access. Opening a sample and selecting a prompt never automatically request inference or publish.

System One Coding is Mithril's coding harness: the model proposes typed building blocks, while the harness constructs source, checks it, and records the outcome. Current inference uses api.mithril.fund with qwen/qwen3.8-27b. Try the registered free pilot.

Ordinary Chat to real Mithril source (2026-10-07 JST)

Code uses the canonical Desktop Chat, sidebar and source editor. A real mithril_code turn generated a .mith report through api.mithril.fund with qwen/qwen3.8-27b. Editing its headline and explicitly recompiling passed infer/query/validate/compile/test. The actual source and receipts were explicitly saved with existing GitHub CLI authentication; the live Pages report was also published and verified. Web GitHub connection and installed Desktop activation are separate checks. App delivery and a separate Mithril-language generation/compile were verified independently.

One coding proposal, Form emission, actual compilation and bounded static semantic checks took 6.263 seconds (1288 input / 127 output tokens), excluding ordinary Chat orchestration and publication. Cost is unknown (null). Two diagnostic attempts failed before the Worker fix; one success proves no general speed, cost or reliability advantage. The model selects a static dashboard/report/directory template and five fields; the harness emits Mithril and the real compiler checks it. Arbitrary application logic and general UI authoring are unsupported. There is no automatic GitHub save or publication, and browser-reported receipts are not signed third-party attestations.

Historical To-do harness (CLJK)

1. A human defines the task, available primitives, types, dependencies and fixed acceptance checks. 2. For each stage and AST hole, the harness presents only compatible choices. The completion-toggle stage has boolean arguments, constants and conditionals. The count stage can use the verified toggle function, vector filtering and counting. 3. Mithril API proposes two typed function bodies in one call. The harness validates types and fixed acceptance checks; confidence alone cannot accept code. 4. The harness emits two CLJK source files, preserves unrelated definitions, and runs independent fixed checks. A receipt records Mithril API IDs, actual tokens, timing and verification. Unknown API charges remain null. Invalid proposals do not become source. These AST and 511-state checks do not prove native CLJK compilation. 5. The browser assembles a TodoMVC starter around the verified kernel. You can inspect/edit/export files, connect GitHub, create a repository, save a commit and explicitly publish it to GitHub Pages.

The historical To-do mode generates completion toggle and unfinished count only. UI, editing, bulk operations, URL filters, local persistence and WebAssembly integration are maintained starter code. Arbitrary repository execution, UI/UX generation, API generation and automatic expansion of the block catalog are future work. Your brief does not create new capabilities outside this catalog. Manual edits are outside the original proof.

Register and try free

Open Mithril, register/sign in, then open System One Coding. No OpenRouter key or GitHub token is needed for a free run. The existing Mithril browser session authorizes the trial. GitHub credentials are needed only to save or publish to your repository.

The pilot allows 50 attempts per account per UTC day, with 100 attempts per UTC day across the service. Accepted attempts, including failure, a busy runner or an unknown outcome, consume a slot. Invalid or unauthenticated requests do not. Replaying the same request ID returns its stored result without another model call. The server uses one persistent transactional quota authority, not browser storage. Generation uses api.mithril.fund/v1/chat/completions with qwen/qwen3.8-27b and its independent authentication, allowance and policy. Desktop uses the selected Hermes profile’s Mithril token; Web uses a Mithril session or token. OpenRouter keys are rejected. GitHub credentials are used only for repository operations.

Historical coding-method comparison

Jev is currently absent from the Mithril API catalog and needs a Decisions contract unavailable on that API. No new OpenRouter call is made to fill this gap. Historical records and current availability are separate from today's Mithril-language pilot.

Measured 2026-10-06T07:33:38.924Z (JST date 2026-10-06), on the same local Node/NBB host through OpenRouter. Five rounds alternate method order; up to four attempts each. Every method must produce the same two CLJK function bodies, preserve the marker and pass both boolean toggle inputs plus all 511 completion vectors of lengths 0–8. The generation baselines output JSON expressions admitted by a restricted grammar before source emission; rejected outputs receive the same generic repair message. This is a small constrained function task, not SWE-bench or general repository coding.

Time runs from caller start through response parsing, admission, source emission and verifier completion. System One includes shared harness setup, receipts and replay checking; the other methods use a smaller admission/checking adapter. Verification processes differ (two parallel per-function checks versus one combined checker). This is a measured comparison of these implementations, not an isolated model-speed test. UI authoring, compile/deploy, network startup, electricity, hardware, human development and training are excluded. API USD comes from actual provider usage receipts, including rejected outputs and repair calls; token columns are medians. No unknown charge is treated as zero. Template reuse requires a solution already known by the developer. Raw 20-run records and reproduction source are available. Provider usage receipts report $0.003558784 in total; settled invoices and total operating costs are not established.

For this task Qwen's median is faster and cheaper than Jev; Gemini's median is also faster and cheaper. Reusing the known template is fastest with zero model API charges. System One's current value is its controlled choice space, dependency-aware composition, verifiable source and replayable evidence. It has not demonstrated a general speed, cost or accuracy advantage. Five successful runs on one tiny task do not establish a general reliability rate.

Historical editor recording

Local Jev experiment with test authentication, 2.631 seconds through source update. This is separate from current Mithril API generation. Recorded measurement

Browser performance is a separate measurement

The TodoMVC comparison measures application interaction and compares the maintained starter with Vanilla ES6. Its Speedometer 3.1 baseline excludes Mithril. These results do not measure coding-agent speed or prove an official Speedometer score for Mithril.

Jev and CLEF

The dated benchmark above used Jev through OpenRouter for typically eight state-dependent choices. The current Mithril API path proposes a typed AST in one call; those historical prices and timings are not current API measurements. Cloudflare CLEF describes a decision-model approach compatible with Jev/System One. CLEF is a possible local/training backend; the deployed pilot does not use a locally trained CLEF model. Earlier local attempts did not qualify, and no training gain is claimed.

Extending the harness

For UI/UX, logic and API stages, define separate typed catalogs and verifiers. For example a layout stage may choose a maintained component; an API stage must select a reviewed contract, authentication and input-validation block. Admit a stage only when its dependencies and check inputs are available. Keep model decisions as proposals; the harness owns types, admissible paths, execution limits and publication gates. Expand the catalog with held-out tasks and track all failures, repair counts, wall time and actual charges before claiming broader capability.