Add repository guidelines and update AI SDK to v2

Change-Id: Ib00b7ee5f39911b58a15674bc50700267018cdbc
Signed-off-by: Thomas Kosiewski <tk@coder.com>

AGENTS.md

@@ -0,0 +1,39 @@
+# Repository Guidelines
+
+## Project Structure & Module Organization
+- `src/`: TypeScript sources. Key files: `main.ts` (CLI entry), `anthropic-proxy.ts` (HTTP proxy), `convert-*.ts` (format converters), `detect-mimetype.ts`, `json-schema.ts`.
+- `dist/`: Bundled CLI entry `main.js` (created by build).
+- `package.json`, `bun.lock`: Bun-based build and deps; `bin.anyclaude` points to `dist/main.js`.
+- `flake.nix`, `.envrc`: Nix/direnv developer shell and formatters.
+- Assets/config: `README.md`, `CLAUDE.md`, `tsconfig.json`, `demo.png`.
+
+## Build, Test, and Development Commands
+- Install: `bun install`.
+- Build: `bun run build` (outputs `dist/main.js` with Node shebang).
+- Run CLI (after build): `./dist/main.js --model openai/gpt-5-mini`.
+- Dev run (no build):
+  - `PROXY_ONLY=true bun run src/main.ts` (prints proxy URL)
+  - `OPENAI_API_KEY=... bun run src/main.ts --model openai/gpt-5-mini`
+- Nix shell: `direnv allow` (or `nix develop`); format Nix/shell files with `nix fmt`.
+
+## Coding Style & Naming Conventions
+- Language: TypeScript (ESNext, strict mode enabled).
+- Indentation: 2 spaces; keep lines reasonable; use explicit imports (`verbatimModuleSyntax`).
+- Files: kebab-case `.ts` (e.g., `convert-to-anthropic-stream.ts`).
+- Names: `camelCase` for variables/functions; `PascalCase` for types/classes.
+- Exports: prefer named exports; keep modules single‑purpose and small.
+
+## Testing Guidelines
+- No test runner is configured yet. If adding tests:
+  - Place under `src/**/*.test.ts` or `src/__tests__/`.
+  - Prioritize pure units (converters, schema, MIME detection). Avoid live provider calls by default; gate with env vars.
+  - Add a `test` script in `package.json` and document how to run it in `README.md`.
+
+## Commit & Pull Request Guidelines
+- Commits: imperative, concise subjects (e.g., "Add Nix development environment and Claude guidance file"). Include rationale in the body when helpful.
+- PRs: clear description, linked issues, commands used to verify (with relevant env vars), and expected behavior. Avoid committing secrets; scrub logs.
+- Keep scope small; update `README.md`/`CLAUDE.md` when behavior or env vars change.
+
+## Security & Configuration Tips
+- Never commit API keys. Use `direnv` for local secrets and keep `.envrc` minimal.
+- Provider envs: `OPENAI_*`, `GOOGLE_*`, `XAI_*`, `AZURE_*`, optional `ANTHROPIC_*`. Use `PROXY_ONLY=true` to inspect the proxy without launching Claude.