Error handling (expected/unexpected/form/API)

Generated from mcp/patterns.registry.json — do not edit by hand; change the registry and run bun run patterns:build.

Index card — the docs below are the canonical explanation; deep-tier pattern pages additionally carry invariants and emulation notes.

Category: Architecture & Request Pipeline · Tier: light · Risk: low — structural pattern, no external services

Classifies errors into expected, unexpected, form, and API categories, each handled by a distinct SvelteKit mechanism (error(), handleError, fail(), json()).

When to use: Reach for it when deciding how to surface a failure from a load function, form action, or API endpoint.

Docs

• docs/blueprint/error-handling.md (GitHub · GitLab)

Code

• src/lib/server/errors/ (GitHub · GitLab)
• src/lib/errors/ (GitHub · GitLab)

Proof

• /showcases/shell/errors

Machine-readable record: architecture-error-handling in mcp/patterns.registry.json.