AI Draft

Capabilities

Capability	API
Password	Web Crypto PBKDF2 — two-format parser supporting legacy hashes
SQLite	Stub — throws EdgeUnsupportedError
Server	Stub — throws EdgeUnsupportedError
Filesystem	Read-only via fileStore (fetch-based) — three-layer cap enforcement
Glob	Stub — throws EdgeUnsupportedError
KV ISR	kv-isr.ts — Cloudflare Workers KV-backed ISR adapter

Runtime Contract

edgeRuntime(opts?) returns SlingshotRuntime (frozen). Unsupported capabilities throw descriptive EdgeUnsupportedError rather than failing silently. runtimeCapabilities() provides programmatic introspection.

Edge-specific Details

• readFile() enforces size caps at three layers: declared size, streaming accumulation, post-buffer
• File store timeout uses AbortController for proper cancellation
• Password verification uses constant-time comparison
• EdgePasswordConfigError thrown eagerly when only one of hashPassword/verifyPassword is provided
• KvNamespace is structurally typed — @cloudflare/workers-types is not a dependency
• KV ISR: concurrency-limited fan-out, per-tag serialization locks, bounded memory

Key Files

• src/index.ts — edgeRuntime() factory, all capability implementations
• src/kv-isr.ts — KV-backed ISR cache adapter
• src/errors.ts — EdgeRuntimeError, EdgeUnsupportedError, EdgeFileReadError, EdgeFileSizeExceededError, EdgePasswordConfigError
• src/lib/withAbortTimeout.ts — AbortController-based timeout utility
• src/testing.ts — TEST_EDGE_TIMEOUT_MS, TEST_MAX_FILE_BYTES