Crate grain_plugin_wasm 

WebAssembly Component Model plugin runtime for grain.

Loads .wasm files compiled against the grain:plugin WIT world, instantiates them via wasmtime, and wraps each plugin-declared tool as a grain_agent_core::AgentTool implementation.

Architecture

.grain/plugins/my-tool/
+-- plugin.toml          # manifest (extended with [wasm])
+-- plugin.wasm          # compiled Component Model module

The host provides logging, env-var access, and HTTP primitives. Each host function is gated by the plugin’s declared capabilities in plugin.toml — calls into a denied capability return an error to the guest.

Re-exports

pub use exports::grain::plugin::plugin as wit_plugin;

pub use grain::plugin::host as wit_host;

Modules

exports

grain

Structs

CallToolResult

Owned result from a tool call (mirrors the WIT tool-result).

Capabilities

Per-plugin capabilities the host enforces.

GrainPlugin

Auto-generated bindings for an instance a component which implements the world grain-plugin.

GrainPluginIndices

Auto-generated bindings for index of the exports of grain-plugin.

GrainPluginPre

Auto-generated bindings for a pre-instantiated version of a component which implements the world grain-plugin.

HookDef

One hook subscription declared by a v2 plugin.

LoadedPlugin

A successfully loaded WASM plugin.

OrchestrationDef

Optional orchestration metadata exported by v2 plugins.

PluginInfo

Plugin metadata (mirrors the WIT plugin-info record but is owned / cloneable for storage outside the store).

PluginState

State stored in the wasmtime Store<T>.

RoleDef

One model-role slot declared by a v2 plugin.

ToolDef

Tool definition (mirrors the WIT tool-def record, owned).

UiHeader

Optional UI header override requested by a v2 plugin.

WasmPluginRuntime

Owns the wasmtime engine and can load + call plugins.

WasmTool

One tool exported by a WASM plugin, presented as an AgentTool.

Enums

HookPoint

Lifecycle point names supported by the v2 orchestration surface.

HostAction

Host action requested by a v2 plugin hook.

WasmPluginError

Type Aliases

LogSink

Host log callback. Called for every log host import the guest invokes (after the log capability gate). Arguments: severity tag ("debug" | "info" | "warn" | "error"), plugin name, message.