feat(llm): add LLMEvent.is.* camelCase narrowing helpers

Schema.toTaggedUnion('type') already provides LLMEvent.guards but uses
kebab-case bracket access (LLMEvent.guards['tool-call']). Adds an LLMEvent.is
namespace with camelCase aliases that delegate to the same guards, so
consumers can write events.filter(LLMEvent.is.toolCall) instead of
events.filter(LLMEvent.guards['tool-call']).

Migrated all callsites in src/llm.ts and the two test files for consistency.
LLMEvent.guards / .match / .cases / .isAnyOf remain available for callers
who want the Effect-canonical API.

packages/llm/src/llm.ts

@@ -191,7 +191,7 @@ export const updateRequest = (input: LLMRequest, patch: Partial<RequestInput>) =
 
 export const outputText = (response: LLMResponse | { readonly events: ReadonlyArray<LLMEvent> }) =>
   response.events
-    .filter(LLMEvent.guards["text-delta"])
+    .filter(LLMEvent.is.textDelta)
     .map((event) => event.text)
     .join("")
 
@@ -204,10 +204,10 @@ export const outputUsage = (response: LLMResponse | { readonly events: ReadonlyA
 }
 
 export const outputToolCalls = (response: LLMResponse | { readonly events: ReadonlyArray<LLMEvent> }) =>
-  response.events.filter(LLMEvent.guards["tool-call"])
+  response.events.filter(LLMEvent.is.toolCall)
 
 export const outputReasoning = (response: LLMResponse | { readonly events: ReadonlyArray<LLMEvent> }) =>
   response.events
-    .filter(LLMEvent.guards["reasoning-delta"])
+    .filter(LLMEvent.is.reasoningDelta)
     .map((event) => event.text)
     .join("")

packages/llm/src/schema.ts

@@ -338,7 +338,7 @@ export const ProviderErrorEvent = Schema.Struct({
 }).annotate({ identifier: "LLM.Event.ProviderError" })
 export type ProviderErrorEvent = Schema.Schema.Type<typeof ProviderErrorEvent>
 
-export const LLMEvent = Schema.Union([
+const llmEventTagged = Schema.Union([
   RequestStart,
   StepStart,
   TextStart,
@@ -353,7 +353,30 @@ export const LLMEvent = Schema.Union([
   RequestFinish,
   ProviderErrorEvent,
 ]).pipe(Schema.toTaggedUnion("type"))
-export type LLMEvent = Schema.Schema.Type<typeof LLMEvent>
+
+/**
+ * camelCase aliases for `LLMEvent.guards` (provided by `Schema.toTaggedUnion`).
+ * Lets consumers write `events.filter(LLMEvent.is.toolCall)` instead of
+ * `events.filter(LLMEvent.guards["tool-call"])`.
+ */
+const llmEventIs = {
+  requestStart: llmEventTagged.guards["request-start"],
+  stepStart: llmEventTagged.guards["step-start"],
+  textStart: llmEventTagged.guards["text-start"],
+  textDelta: llmEventTagged.guards["text-delta"],
+  textEnd: llmEventTagged.guards["text-end"],
+  reasoningDelta: llmEventTagged.guards["reasoning-delta"],
+  toolInputDelta: llmEventTagged.guards["tool-input-delta"],
+  toolCall: llmEventTagged.guards["tool-call"],
+  toolResult: llmEventTagged.guards["tool-result"],
+  toolError: llmEventTagged.guards["tool-error"],
+  stepFinish: llmEventTagged.guards["step-finish"],
+  requestFinish: llmEventTagged.guards["request-finish"],
+  providerError: llmEventTagged.guards["provider-error"],
+} as const
+
+export const LLMEvent = Object.assign(llmEventTagged, { is: llmEventIs })
+export type LLMEvent = Schema.Schema.Type<typeof llmEventTagged>
 
 export class PatchTrace extends Schema.Class<PatchTrace>("LLM.PatchTrace")({
   id: Schema.String,

packages/llm/test/provider/openai-chat-tool-loop.recorded.test.ts

@@ -44,12 +44,12 @@ describe("OpenAI Chat tool-loop recorded", () => {
       // Two model rounds: tool-call + tool-result + final answer. Two
       // `request-finish` events confirm both interactions in the cassette
       // were dispatched in order.
-      const finishes = events.filter(LLMEvent.guards["request-finish"])
+      const finishes = events.filter(LLMEvent.is.requestFinish)
       expect(finishes).toHaveLength(2)
       expect(finishes[0]?.reason).toBe("tool-calls")
       expect(finishes.at(-1)?.reason).toBe("stop")
 
-      const toolResult = events.find(LLMEvent.guards["tool-result"])
+      const toolResult = events.find(LLMEvent.is.toolResult)
       expect(toolResult).toMatchObject({
         type: "tool-result",
         name: "get_weather",

packages/llm/test/tool-runtime.test.ts

@@ -52,7 +52,7 @@ describe("ToolRuntime", () => {
         ),
       )
 
-      const result = events.find(LLMEvent.guards["tool-result"])
+      const result = events.find(LLMEvent.is.toolResult)
       expect(result).toMatchObject({
         type: "tool-result",
         id: "call_1",
@@ -79,10 +79,10 @@ describe("ToolRuntime", () => {
         ),
       )
 
-      const toolError = events.find(LLMEvent.guards["tool-error"])
+      const toolError = events.find(LLMEvent.is.toolError)
       expect(toolError).toMatchObject({ type: "tool-error", id: "call_1", name: "missing_tool" })
       expect(toolError?.message).toContain("Unknown tool")
-      expect(events.find(LLMEvent.guards["tool-result"])).toMatchObject({
+      expect(events.find(LLMEvent.is.toolResult)).toMatchObject({
         type: "tool-result",
         id: "call_1",
         name: "missing_tool",
@@ -106,7 +106,7 @@ describe("ToolRuntime", () => {
         ),
       )
 
-      const toolError = events.find(LLMEvent.guards["tool-error"])
+      const toolError = events.find(LLMEvent.is.toolError)
       expect(toolError).toMatchObject({ type: "tool-error", id: "call_1", name: "get_weather" })
       expect(toolError?.message).toContain("Invalid tool input")
     }),
@@ -127,7 +127,7 @@ describe("ToolRuntime", () => {
         ),
       )
 
-      const toolError = events.find(LLMEvent.guards["tool-error"])
+      const toolError = events.find(LLMEvent.is.toolError)
       expect(toolError).toMatchObject({ type: "tool-error", id: "call_1", name: "get_weather" })
       expect(toolError?.message).toBe("Weather lookup failed for FAIL")
     }),
@@ -166,7 +166,7 @@ describe("ToolRuntime", () => {
         ),
       )
 
-      expect(events.filter(LLMEvent.guards["request-finish"])).toHaveLength(2)
+      expect(events.filter(LLMEvent.is.requestFinish)).toHaveLength(2)
     }),
   )
 
@@ -186,8 +186,8 @@ describe("ToolRuntime", () => {
         }).pipe(Stream.runCollect, Effect.provide(layer)),
       )
 
-      expect(events.filter(LLMEvent.guards["request-finish"])).toHaveLength(1)
-      expect(events.find(LLMEvent.guards["tool-result"])).toBeUndefined()
+      expect(events.filter(LLMEvent.is.requestFinish)).toHaveLength(1)
+      expect(events.find(LLMEvent.is.toolResult)).toBeUndefined()
     }),
   )
 
@@ -238,8 +238,8 @@ describe("ToolRuntime", () => {
       )
 
       expect(streams).toBe(1)
-      expect(events.find(LLMEvent.guards["tool-error"])).toBeUndefined()
-      expect(events.filter(LLMEvent.guards["tool-call"])).toEqual([
+      expect(events.find(LLMEvent.is.toolError)).toBeUndefined()
+      expect(events.filter(LLMEvent.is.toolCall)).toEqual([
         {
           type: "tool-call",
           id: "srvtoolu_abc",
@@ -276,7 +276,7 @@ describe("ToolRuntime", () => {
         ),
       )
 
-      const results = events.filter(LLMEvent.guards["tool-result"])
+      const results = events.filter(LLMEvent.is.toolResult)
       expect(results).toHaveLength(2)
       expect(results.map((event) => event.id).toSorted()).toEqual(["c1", "c2"])
     }),