feat(harness): expose tool call input and plugin load failures as events

- ToolStarted carries the call's arguments and the tool's optional label, so clients can show what a tool is doing as soon as it starts (COD-85). - A configured plugin that is not installed now also publishes plugin.updated (status "failed") with the message, declaring file and session, so clients can show the advice to the user (COD-90). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
sanchitrk · Sep 30, 2026 · Sep 24, 2026 · Sep 25, 2026 · Sep 26, 2026 · Sep 26, 2026
commit 1988fe73370be691e7b97dfd75ed284a63ceed08
diff --git a/packages/harness/src/event/list.ts b/packages/harness/src/event/list.ts
@@ -160,7 +160,14 @@ export type LLMFailed = typeof LLMFailed.Type;
 
 export const ToolStarted = EventSchema.define({
 	type: "session.tool.started",
-	schema: { ...LLMFields, callID: Schema.String, name: Schema.String },
+	schema: {
+		...LLMFields,
+		callID: Schema.String,
+		name: Schema.String,
+		/** The tool's display label, when its definition declares one. */
+		label: optional(Schema.String),
+		arguments: Schema.Record(Schema.String, Schema.Json),
+	},
 });
 export type ToolStarted = typeof ToolStarted.Type;
 

diff --git a/packages/harness/src/runner/loop.ts b/packages/harness/src/runner/loop.ts
@@ -176,6 +176,8 @@ export const layer = (options: Options = {}) =>
 								messageId,
 								callID: call.callID,
 								name: call.name,
+								label: snapshot.tools.defs.find((def) => def.name === call.name)?.label,
+								arguments: call.arguments,
 							});
 							const handled = yield* snapshot.tools
 								.handle(call, {

diff --git a/packages/harness/src/state/state.ts b/packages/harness/src/state/state.ts
@@ -397,11 +397,18 @@ export const layer = (
 								? one.entry === reference
 								: "package" in one.entry && one.entry.package === reference,
 						);
-						yield* Effect.logWarning(
-							`plugin ${reference} is configured but not loaded — run \`codework plugin install\`${
-								where === undefined ? "" : ` (declared in ${where.file})`
-							}`,
-						);
+						const error = `plugin ${reference} is configured but not loaded — run \`codework plugin install\`${
+							where === undefined ? "" : ` (declared in ${where.file})`
+						}`;
+						yield* Effect.logWarning(error);
+						// The advice is for the user, who may not be reading this process's logs.
+						yield* eventService.publish(EventList.PluginUpdated, {
+							status: "failed",
+							reference,
+							error,
+							...(where === undefined ? {} : { file: where.file }),
+							sessionId,
+						});
 					}
 
 					const contributions = yield* setup(chosen.selection, {