Development journal for Urd, a declarative schema system for interactive worlds.https://urd.dev/https://urd.dev/articles/forge-two-days/https://urd.dev/articles/forge-two-days/Eighteen days from empty repository to: a declarative schema language with formal grammar, a six-phase Rust compiler (8,189 lines, 634 tests, 74 diagnostics), a queryable semantic analysis layer (FactSet IR, LSP, MCP server), a WASM playground with 25 semantic reference kinds, a documentation website with six interactive islands, 27 design documents, and an 88-view desktop IDE built in two days from architecture specification. Almost entirely AI-generated code. Opus 4.6 and Sonnet 4.6 represent a phase shift. The project will likely be parked as a historical record. Every brief is public. The challenge is open: one-shot the entire project from the specifications.Sat, 28 Feb 2026 00:00:00 GMThttps://urd.dev/articles/urd-forge/https://urd.dev/articles/urd-forge/Urd Forge is a Tauri-based desktop IDE for authoring Urd worlds — Blender-style tiling layout, 85+ specialised views (spreadsheets, node graphs, matrices, inspectors, visualisations) projected over a single compiler output, Rust backend via IPC, Svelte 5 frontend, CodeMirror 6 editor. Full architecture specification complete: BSP zone tree, command registry, message bus, projection layer, workspace management, theme engine, eight-phase implementation plan. Framework and application layers cleanly separated — the generic IDE framework has no knowledge of Urd.Thu, 26 Feb 2026 00:00:00 GMThttps://urd.dev/articles/reference-manual-v0114/https://urd.dev/articles/reference-manual-v0114/The reference manual catches up with seven compiler releases. Updated from v0.1.7 (554 tests, 69 diagnostics, five phases) to v0.1.14 (634 tests, 74 diagnostics, six phases). New sections cover the ANALYZE phase and its five novel FactSet-derived diagnostics, the semantic diff engine with CLI subcommands, the DefinitionIndex for IDE integration, and full CLI reference. The schema language and JSON format are unchanged — all updates are on the compiler's tooling surface.Thu, 26 Feb 2026 00:00:00 GMThttps://urd.dev/articles/playground-editor/https://urd.dev/articles/playground-editor/The playground code editor is now a FactSet-powered semantic tool mirroring the Rust-side LSP. 25 reference kinds in the cursor resolver — tooltips draw from the compiler's queryable semantic graph for real containment chains, read/write counts, and enum validation rather than static documentation. Inline diagnostics, autocomplete, go-to-definition, and full syntax coverage including the `!` blocked message marker. Also adds a video introduction lightbox on the homepage.Wed, 25 Feb 2026 00:00:00 GMThttps://urd.dev/articles/semantic-gate-closed/https://urd.dev/articles/semantic-gate-closed/Six briefs, three tiers, one gate — closed. Novel FactSet diagnostics (SF-1A), PropertyDependencyIndex (SF-2), graph visualisation (SF-3), semantic diff engine (SF-4), LSP server with diagnostics/go-to-def/hover/autocomplete (SF-5), and an eight-tool MCP server for AI agents (SF-6). Compiler 0.1.13. 626 tests across three crates. The queryable world is complete. The runtime gate (Wyrd) is next.Tue, 24 Feb 2026 00:00:00 GMThttps://urd.dev/articles/semantic-first/https://urd.dev/articles/semantic-first/Why we are building FactSet tooling before the runtime. The compiler's queryable semantic graph enables explain mode, cache invalidation, AI planning, and static analysis as queries over six tuple types — capabilities that execution-first runtimes cannot offer without simulation.Mon, 23 Feb 2026 00:00:00 GMThttps://urd.dev/documents/urd-v0.1.7-referencehttps://urd.dev/documents/urd-v0.1.7-referenceA single consolidated reference for the entire system — Schema Markdown syntax, the compiled JSON format, all 69 diagnostic codes, the FactSet analysis IR, and two worked examples (Monty Hall, Two Room Key Puzzle). Written as a practical manual rather than a spec. Start here.Mon, 23 Feb 2026 00:00:00 GMThttps://urd.dev/articles/pre-alpha/https://urd.dev/articles/pre-alpha/All 32 acceptance criteria verified and documented. Nine compiler requirements, eight static analysis checks, eight FactSet IR requirements, and seven specification consistency items — every one passed or resolved. The cross-document audit found and fixed a latent schema divergence in `on_exhausted` goto handling. Compiler 0.1.7. 554 tests. The gate is closed. Pre-alpha begins.Sun, 22 Feb 2026 00:00:00 GMThttps://urd.dev/articles/queryable-semantic-graph/https://urd.dev/articles/queryable-semantic-graph/The compiler now produces a FactSet — a flat, queryable intermediate representation of every resolved relationship in the compiled world. Six fact types (PropertyRead, PropertyWrite, ExitEdge, JumpEdge, ChoiceFact, RuleFact) plus a PropertyDependencyIndex. Extracted after LINK, available on CompilationResult regardless of VALIDATE errors. WASM output now includes serialised facts. 547 tests, zero regressions.Sun, 22 Feb 2026 00:00:00 GMThttps://urd.dev/articles/static-analysis-complete/https://urd.dev/articles/static-analysis-complete/Four new VALIDATE-phase checks close the Static Analysis gate: unreachable location (URD430), orphaned choice (URD432), missing fallthrough (URD433), and section-exit shadowing (URD434). All eight static analysis checks (S1–S8) are now implemented. The playground now shows warnings alongside compiled output. 516 tests, zero regressions.Sat, 21 Feb 2026 00:00:00 GMThttps://urd.dev/articles/v1-completion-gate/https://urd.dev/articles/v1-completion-gate/New planning document defines v1 acceptance criteria across five gates: compiler, runtime, testing, specification consistency, and architectural boundary enforcement. Twenty-one runtime requirements, eight static analysis checks, and a recommended eight-step implementation sequence from spec audit through acceptance verification.Sat, 21 Feb 2026 00:00:00 GMThttps://urd.dev/articles/world-is-not-the-interface/https://urd.dev/articles/world-is-not-the-interface/New essay examines why interactive world systems keep absorbing their presentation layer, how Inform, ink, and articy illustrate the pattern, and what the architectural refusal at the core of Urd enables: deterministic testing, static analysis, multi-interface portability, and AI-native consumption.Sat, 21 Feb 2026 00:00:00 GMThttps://urd.dev/articles/architectural-boundaries/https://urd.dev/articles/architectural-boundaries/New normative governance document defines what belongs in the schema, what belongs in the runtime, and what belongs in neither. Provides a five-question boundary test, five permanent exclusions, and a full audit of every existing v1 field. The document to read first if you want to understand what Urd will — and will not — become.Sat, 21 Feb 2026 00:00:00 GMThttps://urd.dev/articles/schema-check/https://urd.dev/articles/schema-check/Compiler output now validates against the JSON Schema at three levels: CI test suite (7 compiler fixtures), browser playground (lazy-loaded AJV with toggle and traffic light), and the emit phase itself (world names auto-slugified). Compiler 0.1.4. Schema test corpus at 39 fixtures.Fri, 20 Feb 2026 00:00:00 GMThttps://urd.dev/articles/sunken-citadel/https://urd.dev/articles/sunken-citadel/Third patch release. Adds list and entity reference values in frontmatter, implicit `container` property recognition, built-in `-> end` jump target, and two new silent-skip diagnostics (URD430, URD431, URD432). The 1,101-line sunken-citadel stress test compiles with zero errors. 39 new tests. Total: 480 tests, 100% pass rate.Fri, 20 Feb 2026 00:00:00 GMThttps://urd.dev/articles/reserved-propref-fix/https://urd.dev/articles/reserved-propref-fix/Second patch release. Fixes `target.prop` and `player.prop` parsing in narrative conditions — the primary mechanism for filtering entity-targeted choices. Adds LINK phase bypass for reserved bindings and 8 new tests. Total: 441 tests, 100% pass rate.Thu, 19 Feb 2026 00:00:00 GMThttps://github.com/urdwyrd/urd/blob/main/packages/compiler/CHANGELOG.mdhttps://github.com/urdwyrd/urd/blob/main/packages/compiler/CHANGELOG.mdFirst patch release. Fixes silent type mismatches where `int`, `num`, `str` compiled as `string` without warning. Adds range shorthand parsing, URD429 unrecognised type diagnostic, and a formal changelog linked from the playground and test dashboard.Thu, 19 Feb 2026 00:00:00 GMThttps://urd.dev/articles/playground/https://urd.dev/articles/playground/Interactive playground launched. The full five-phase Rust compiler running as WebAssembly in the browser. Type Schema Markdown, get compiled JSON in real time with structured diagnostics. CodeMirror 6 editor with custom language mode, ~67 KB WASM binary, sub-millisecond compilation. Nothing leaves the page.Thu, 19 Feb 2026 00:00:00 GMThttps://urd.dev/articles/spec-driven-compiler/https://urd.dev/articles/spec-driven-compiler/Five-phase Rust compiler built entirely from specifications — 302 tests, 100% pass rate, four canonical fixtures compiling to valid `.urd.json`. The design documents were not amended once during implementation. Human specification, AI implementation, machine verification.Wed, 18 Feb 2026 00:00:00 GMThttps://urd.dev/articles/compiler-test-dashboard/https://urd.dev/articles/compiler-test-dashboard/Live test dashboard on the homepage — 302 tests across seven phases, 100% pass rate, with expandable phase breakdowns, architecture compliance checks, and per-file compilation benchmarks. Generated from `cargo test` output on every deploy. The compiler is not a claim; it is a number you can verify.Wed, 18 Feb 2026 00:00:00 GMThttps://urd.dev/articles/compiler-briefs/https://urd.dev/articles/compiler-briefs/Six engineering briefs now specify the compiler before implementation begins — one architecture brief defining shared data structures and five phase briefs (PARSE, IMPORT, LINK, VALIDATE, EMIT) with interface contracts, diagnostic catalogues, and 150+ acceptance test cases.Tue, 17 Feb 2026 00:00:00 GMThttps://urd.dev/articles/entering-validation/https://urd.dev/articles/entering-validation/Formalisation is complete — PEG grammar for input, JSON Schema for output, both tested and passing. The project moves to validation: build the compiler, compile the Monty Hall problem, run it ten thousand times, and prove the switching advantage converges to two-thirds.Tue, 17 Feb 2026 00:00:00 GMThttps://urd.dev/articles/how-the-site-works/https://urd.dev/articles/how-the-site-works/A walkthrough of the tech stack behind urd.dev — Astro 5 static generation, Svelte 5 islands with deferred hydration, Tailwind v4 driven by a 600-line design brief, self-hosted fonts, path-filtered GitHub Actions deployment, and Cloudflare Pages hosting. Everything traces back to a design system that lives in the repository.Tue, 17 Feb 2026 00:00:00 GMThttps://urd.dev/articles/peg-grammar/https://urd.dev/articles/peg-grammar/The input-side formalisation artifact is complete: a PEG grammar (Rust/pest) that validates `.urd.md` source files syntactically. Covers the full Schema Markdown syntax — headings, choices, conditions, effects, rule blocks, and five resolved ambiguities. Tested against 12 fixtures — 7 valid, 5 invalid — all passing.Mon, 16 Feb 2026 00:00:00 GMThttps://urd.dev/articles/json-schema/https://urd.dev/articles/json-schema/The output-side formalisation artifact is complete: a JSON Schema (draft 2020-12) that validates compiled `.urd.json` files structurally. Covers all eight top-level blocks, nine reusable sub-schemas, conditional type validation, and recursive dialogue choices. Tested against 32 fixtures — 7 positive, 25 negative — all passing.Mon, 16 Feb 2026 00:00:00 GMThttps://urd.dev/articles/a-human-entered-the-room/https://urd.dev/articles/a-human-entered-the-room/Urd was posted to an interactive fiction community. The feedback was expert, direct, and valuable — exposing AI-generated historical inaccuracies, sycophantic self-reviews, and overclaiming. This article records what they said, what it revealed, and what changed.Mon, 16 Feb 2026 00:00:00 GMThttps://urd.dev/https://urd.dev/The locked prose specifications have been translated into a formal PEG grammar design — a machine-readable definition of valid Schema Markdown. A detailed execution brief covers package structure, parser tooling (Rust/pest), a twelve-file validation corpus extracted from the spec examples, and resolutions for every ambiguity identified during the translation. This is the bridge from design to implementation: the first code package in the monorepo, and the foundation the compiler will build on.Sun, 15 Feb 2026 00:00:00 GMThttps://urd.dev/https://urd.dev/The full V1 design specification and V0.1 Schema Markdown spec have been finalised and independently reviewed by four frontier AI models — Gemini 3, GPT-5.2, DeepSeek-V3.2, and Grok. All four rated the suite ready for implementation. The schema contract, authoring format, and runtime architecture are now locked as the foundation for the build phase.Fri, 13 Feb 2026 00:00:00 GMThttps://urd.dev/https://urd.dev/Svelte 5 island component for filterable document cards. Category filter bar with taxonomy-driven colours. Expanded card view with full synopsis and tags. Briefs completed: document-explorer, homepage-and-documents.Wed, 11 Feb 2026 00:00:00 GMThttps://urd.dev/https://urd.dev/GitHub Actions workflow deploying on push to main, path-filtered to sites/urd.dev/**. Live at urd.dev. Brief: 2026-02-11-cloudflare-pages-deploy.mdWed, 11 Feb 2026 00:00:00 GMT