diff --git a/packages/agent/docs/agent-harness.md b/packages/agent/docs/agent-harness.md
index 16e0664c..2d30dc2d 100644
--- a/packages/agent/docs/agent-harness.md
+++ b/packages/agent/docs/agent-harness.md
@@ -175,6 +175,16 @@ Summary:
 
 Event payloads describe what is happening. Harness getters describe latest config for future snapshots. Hook and listener settlement should be awaited in lifecycle order where possible; transport backpressure is handled below the harness by `AssistantMessageStream`, so the harness does not need a separate async event queue merely to keep SSE or websocket reads flowing.
 
+### Summarization retry events
+
+When the harness is configured with a retry policy, generated compaction and branch-summary requests emit retry lifecycle events for transient provider errors:
+
+- `retry_scheduled`: a retry was scheduled. Includes `operation: "compaction" | "branch_summary"`, `attempt`, `maxAttempts`, `delayMs`, and `errorMessage`.
+- `retry_attempt_start`: the backoff delay completed and the retried summarization request is starting. Includes `operation`.
+- `retry_finished`: the retry loop finished after success, exhaustion, or abort. Includes `operation`.
+
+These events are observational and do not accept hook results.
+
 ## Planned session facade
 
 Extensions should eventually interact with a harness-scoped `HarnessSession` facade rather than the raw session. The facade should wrap the internal session and enforce harness pending-write ordering semantics. Once this exists, hooks and event listeners can receive a context that exposes the full `AgentHarness` plus the session facade without giving direct access to unordered raw session writes.
diff --git a/packages/coding-agent/docs/json.md b/packages/coding-agent/docs/json.md
index e9a48cbd..a9d28cbc 100644
--- a/packages/coding-agent/docs/json.md
+++ b/packages/coding-agent/docs/json.md
@@ -17,7 +17,11 @@ type AgentSessionEvent =
   | { type: "compaction_start"; reason: "manual" | "threshold" | "overflow" }
   | { type: "compaction_end"; reason: "manual" | "threshold" | "overflow"; result: CompactionResult | undefined; aborted: boolean; willRetry: boolean; errorMessage?: string }
   | { type: "auto_retry_start"; attempt: number; maxAttempts: number; delayMs: number; errorMessage: string }
-  | { type: "auto_retry_end"; success: boolean; attempt: number; finalError?: string };
+  | { type: "auto_retry_end"; success: boolean; attempt: number; finalError?: string }
+  | { type: "summarization_retry_scheduled"; attempt: number; maxAttempts: number; delayMs: number; errorMessage: string }
+  | { type: "summarization_retry_attempt_start"; source: "branchSummary" }
+  | { type: "summarization_retry_attempt_start"; source: "compaction"; reason: "manual" | "threshold" | "overflow" }
+  | { type: "summarization_retry_finished" };
 ```
 
 `queue_update` emits the full pending steering and follow-up queues whenever they change. `compaction_start` and `compaction_end` cover both manual and automatic compaction.
diff --git a/packages/coding-agent/docs/rpc.md b/packages/coding-agent/docs/rpc.md
index 2151b4b3..7e86feca 100644
--- a/packages/coding-agent/docs/rpc.md
+++ b/packages/coding-agent/docs/rpc.md
@@ -851,6 +851,9 @@ Events are streamed to stdout as JSON lines during agent operation. Events do NO
 | `compaction_end` | Compaction completes |
 | `auto_retry_start` | Auto-retry begins (after transient error) |
 | `auto_retry_end` | Auto-retry completes (success or final failure) |
+| `summarization_retry_scheduled` | Retry scheduled for a transient compaction or branch-summary summarization error |
+| `summarization_retry_attempt_start` | Retried summarization request starts |
+| `summarization_retry_finished` | Summarization retry loop completes |
 | `extension_error` | Extension threw an error |
 
 ### agent_start
@@ -1077,6 +1080,36 @@ On final failure (max retries exceeded):
 }
 ```
 
+### summarization_retry_scheduled / summarization_retry_attempt_start / summarization_retry_finished
+
+Emitted when compaction or branch-summary summarization retries after a transient provider error. These events use the same retry settings as automatic assistant-turn retries.
+
+```json
+{
+  "type": "summarization_retry_scheduled",
+  "attempt": 1,
+  "maxAttempts": 3,
+  "delayMs": 2000,
+  "errorMessage": "terminated"
+}
+```
+
+```json
+{
+  "type": "summarization_retry_attempt_start",
+  "source": "compaction",
+  "reason": "threshold"
+}
+```
+
+For branch summaries, `source` is `"branchSummary"` and no `reason` is present.
+
+```json
+{
+  "type": "summarization_retry_finished"
+}
+```
+
 ### extension_error
 
 Emitted when an extension throws an error.
diff --git a/packages/coding-agent/docs/sdk.md b/packages/coding-agent/docs/sdk.md
index 9fcfdeec..1dc32a14 100644
--- a/packages/coding-agent/docs/sdk.md
+++ b/packages/coding-agent/docs/sdk.md
@@ -319,6 +319,9 @@ session.subscribe((event) => {
     case "compaction_end":
     case "auto_retry_start":
     case "auto_retry_end":
+    case "summarization_retry_scheduled":
+    case "summarization_retry_attempt_start":
+    case "summarization_retry_finished":
       break;
   }
 });