the catalog

53 specifications, 966 graded capabilities

Every spec is a versioned tree of capabilities. Read one, build against it, then submit a grade — free, no account.

specs.json — the whole catalog as one file, for agents.

apps 11

Calculator Arithmetic that behaves the way a pocket calculator does, including the awkward parts. 17 capabilities · reference Chat App Rooms, message history, presence and delivery state for a realtime chat client. 16 capabilities · reference Excalidraw Hand-drawn-style whiteboard: shapes, freedraw, selection, export and live collaboration. 15 capabilities · extracted Expense Tracker Categorised spending with budgets, recurring entries and monthly totals. 14 capabilities · reference Kanban Board Columns and draggable cards with WIP limits, filtering and persistence. 17 capabilities · reference Markdown Editor Live preview, formatting shortcuts, and a clean round-trip to disk. 14 capabilities · reference Obsidian (desktop) Local-first markdown vault: wikilinks, backlinks, graph view and a plugin surface. 19 capabilities · extracted Pomodoro Timer Work/break cycles with notifications, skip/reset and session history. 12 capabilities · reference RSS Reader Feed subscriptions, unread tracking, folders and offline reading. 14 capabilities · reference TodoMVC The canonical todo app — the reference specification every framework implements. 20 capabilities · reference Weather Dashboard Current conditions, multi-day forecast, saved locations and units. 13 capabilities · reference

services 7

Auth Service Registration, sessions, password reset, OAuth providers and role checks. 15 capabilities · reference Feature Flag Service Evaluate flags per user with targeting, rollouts and audit. 18 capabilities · reference File Upload Service Multipart uploads, validation, storage backends and signed URLs. 13 capabilities · reference Job Queue Enqueue background work and run it reliably: retries, scheduling, dead letters. 19 capabilities · reference PocketBase Single-binary backend: SQLite records, realtime subscriptions, auth, files and hooks. 14 capabilities · extracted URL Shortener Slug generation, redirects, click analytics, expiry and custom domains. 19 capabilities · reference Webhook Relay Receive, verify, queue and deliver webhooks with retries and replay. 18 capabilities · reference

engines 6

Diff Engine Compute and apply differences between two texts. 15 capabilities · reference JSON Parser Parse and serialise JSON per RFC 8259, with useful errors. 15 capabilities · reference KV Store Get/put/delete, iteration, atomic batches, durability and compaction. 12 capabilities · reference Markdown Parser CommonMark-shaped parser: text in, structured document or HTML out. 18 capabilities · reference SQLite Embedded SQL engine: transactions, indexes, WAL, triggers and extensions. 18 capabilities · extracted Template Engine Render templates against data: interpolation, control flow, partials, escaping. 16 capabilities · reference

cli 4

HTTP Client CLI Make HTTP requests from the terminal and read the answer without effort. 17 capabilities · reference JSON Tool CLI Query, filter and reshape JSON from a pipe, with exit codes that mean something. 12 capabilities · reference ripgrep Recursive regex search with gitignore awareness, type filters and fast output. 15 capabilities · extracted Todo CLI Manage a task list from the terminal, with output humans and scripts can both read. 16 capabilities · reference

formats 4

CSV (RFC 4180) Comma-separated values — the format everyone thinks is simple. 16 capabilities · reference JSON Web Token Signed claims in a URL-safe string — and the ways it goes wrong. 15 capabilities · reference Semantic Versioning 2.0.0 Version numbers that carry a promise about compatibility. 15 capabilities · reference YAML 1.2 Human-friendly data serialisation — indentation, anchors and famous footguns. 15 capabilities · reference

games 4

2048 Sliding tile puzzle: merge equal tiles on a 4×4 grid until 2048 appears. 17 capabilities · reference Conway's Game of Life Cellular automaton: cells live, die and reproduce by neighbour count. 16 capabilities · reference Minesweeper Uncover every safe cell on a mined grid using neighbour counts. 17 capabilities · reference Snake Grow a snake by eating food without hitting the wall or yourself. 16 capabilities · reference

goods 3

Coffee Grinder A deliberately non-software spec: same tree, same grading, no code anywhere. 19 capabilities · reference Office Chair What actually differs between chairs, once marketing is removed. 18 capabilities · reference Running Shoe The second non-software example — proof the tree is domain-agnostic. 18 capabilities · reference

hardware 3

Laptop What to compare when comparing portable computers. 21 capabilities · reference Smartphone The comparison people actually make before spending money. 20 capabilities · reference Solid-State Drive Beyond the headline sequential number. 17 capabilities · reference

libraries 3

Date & Time Library Instants, zoned times, durations and formatting — correct across zones and DST. 18 capabilities · reference Shell (TS workbench) Reusable VS Code-style shell: activity bar, sidebars, toolbar, status bar, toasts. 22 capabilities · extracted Validation Library Declare a schema, validate unknown input, get typed data or precise errors. 20 capabilities · reference

protocols 3

HTTP Caching Freshness, validation and invalidation between client, proxy and origin. 16 capabilities · reference OAuth 2.1 Authorization Code + PKCE Delegated authorisation done the way current guidance requires. 17 capabilities · reference WebSocket A persistent bidirectional connection, from handshake to graceful close. 16 capabilities · reference

layers 2

NanoChat.NET — engine layer The .NET port's engine capabilities, as reachable from code. 16 capabilities · extracted NanoChat.NET — UI + MCP surface What the desktop UI and MCP server actually expose of that same engine. 16 capabilities · extracted

ports 2

nanochat (Python) Karpathy's nanochat — tokenizer, pretraining, fine-tuning, RL and inference. 65 capabilities · extracted NanoChat.NET The .NET port of nanochat, graded capability by capability against the Python reference. 65 capabilities · extracted

generators 1

Hugo Static site generator: content model, templates, taxonomies and asset pipelines. 14 capabilities · extracted