diff --git a/src/cli/handlers/observation.ts b/src/cli/handlers/observation.ts
index b498976f..bee81bac 100644
--- a/src/cli/handlers/observation.ts
+++ b/src/cli/handlers/observation.ts
@@ -24,7 +24,8 @@ export const observationHandler: EventHandler = {
     const { sessionId, cwd, toolName, toolInput, toolResponse } = input;
 
     if (!toolName) {
-      throw new Error('observationHandler requires toolName');
+      // No tool name provided - skip observation gracefully
+      return { continue: true, suppressOutput: true, exitCode: HOOK_EXIT_CODES.SUCCESS };
     }
 
     const port = getWorkerPort();
diff --git a/src/cli/handlers/summarize.ts b/src/cli/handlers/summarize.ts
index bd0756ae..19cd46d9 100644
--- a/src/cli/handlers/summarize.ts
+++ b/src/cli/handlers/summarize.ts
@@ -29,7 +29,9 @@ export const summarizeHandler: EventHandler = {
 
     // Validate required fields before processing
     if (!transcriptPath) {
-      throw new Error(`Missing transcriptPath in Stop hook input for session ${sessionId}`);
+      // No transcript available - skip summary gracefully (not an error)
+      logger.debug('HOOK', `No transcriptPath in Stop hook input for session ${sessionId} - skipping summary`);
+      return { continue: true, suppressOutput: true, exitCode: HOOK_EXIT_CODES.SUCCESS };
     }
 
     // Extract last assistant message from transcript (the work Claude did)