memory-module-sdk.md

Memory Module SDK (WASM)

Scope

Memory extensions are WASM-only modules. Native third-party memory drivers are not loaded into root.

ABI (MVP)

Required module exports:

• handle_upsert
• handle_query
• handle_read
• handle_delete
• handle_health

Host imports (memory_host):

• kv_get, kv_put
• blob_get, blob_put
• emit_metric, log
• clock_now_ms

Explicitly not available in MVP:

• host network fetch
• shell/command execution

WIT contract: crates/kelvin-memory-module-sdk/wit/memory-module.wit

Manifest

Modules declare MemoryModuleManifest:

• module_id, version, api_version
• capabilities
• required_host_features
• entrypoint, publisher, signature

Controller enforces intersection:

• module manifest capabilities
• JWT delegated capabilities/operations
• platform enabled provider features

Reference Module

Reference module artifacts:

• crates/kelvin-memory-module-sdk/examples/memory_echo/memory_echo.wat
• crates/kelvin-memory-module-sdk/examples/memory_echo/manifest.json

Authoring Guidance

1. Keep module handlers side-effect minimal and deterministic.
2. Assume host limits may terminate execution at any time.
3. Avoid unbounded loops/allocations.
4. Fail with explicit non-zero result codes only for module-local errors.