fix(llm): honor DeepSeek SSE keep-alives

packages/llm/llm-deepseek/src/adapter.ts

@@ -215,7 +215,13 @@ export class DeepSeekAdapter extends LlmAdapter {
       ? consumer.signal
       : AbortSignal.any([options.signal, consumer.signal])
     using watchdog = idleWatchdog(upstream, connection.streamIdleTimeoutMs, STREAM_IDLE_TIMEOUT_CODE)
-    const iterator = this.request(options, watchdog.signal, connection, apiKey)[Symbol.asyncIterator]()
+    const iterator = this.request(
+      options,
+      watchdog.signal,
+      connection,
+      apiKey,
+      () => { watchdog.pulse() },
+    )[Symbol.asyncIterator]()
     let exhausted = false
     try {
       while (true) {
@@ -256,6 +262,7 @@ export class DeepSeekAdapter extends LlmAdapter {
     signal: AbortSignal,
     connection: DeepSeekConnectionOptions,
     apiKey: string,
+    onComment: () => void,
   ): AsyncIterable<StreamChunk> {
     const body = serializeRequest(options, connection.defaults)
     // Prepared outside the try so the TRANSPORT label below covers exactly the
@@ -321,6 +328,6 @@ export class DeepSeekAdapter extends LlmAdapter {
       throw new LlmError('DeepSeek API returned no response body', 'EMPTY_RESPONSE')
     }
 
-    yield* translate(parseSse(response.body))
+    yield* translate(parseSse(response.body, onComment))
   }
 }

packages/llm/llm-deepseek/src/sse.ts

@@ -1,11 +1,12 @@
 /**
  * Decode an SSE byte stream into event `data` payloads. Framing — chunk
  * reassembly, UTF-8/CRLF/BOM handling, comment and non-data field skipping,
- * multi-`data:` joining — is `eventsource-parser`'s; this module keeps only
- * the DeepSeek protocol: the literal `[DONE]` is yielded so the caller owns
- * final flushing, and EOF before it raises {@link LlmError}. Framing is
- * spec-strict: an event dispatches only on its blank-line terminator, so an
- * unterminated tail at EOF is truncation, not a flushable payload.
+ * multi-`data:` joining — is `eventsource-parser`'s. Comments are reported
+ * only through an optional transport-activity callback. This module keeps the
+ * DeepSeek protocol: the literal `[DONE]` is yielded so the caller owns final
+ * flushing, and EOF before it raises {@link LlmError}. Framing is spec-strict:
+ * an event dispatches only on its blank-line terminator, so an unterminated
+ * tail at EOF is truncation, not a flushable payload.
  *
  * @module dsh-llm-deepseek/sse
  */
@@ -21,12 +22,16 @@ export const DONE = '[DONE]'
  * value and returns; throws `LlmError('STREAM_CLOSED')` when the stream ends
  * without it (truncated response — the model call cannot be trusted).
  * @param stream - raw SSE bytes; reads may split anywhere, including mid-UTF-8 sequence.
+ * @param onComment - optional transport-activity callback; comments never enter the yielded payload stream.
  * @returns each event's data payload in arrival order, the `[DONE]` sentinel last.
  */
-export async function* parseSse(stream: ReadableStream<BufferSource>): AsyncGenerator<string> {
+export async function* parseSse(
+  stream: ReadableStream<BufferSource>,
+  onComment?: (comment: string) => void,
+): AsyncGenerator<string> {
   const events = stream
     .pipeThrough(new TextDecoderStream())
-    .pipeThrough(new EventSourceParserStream())
+    .pipeThrough(new EventSourceParserStream({ onComment }))
   for await (const { data } of events) {
     yield data
     if (data === DONE) return