feat(plugin): allow compaction hook to replace prompt entirely (#5907)

1 files changed, 9 insertions, 3 deletions

diff --git a/packages/plugin/src/index.ts b/packages/plugin/src/index.ts
index 487e6ed3e..fbc0e710c 100644
--- a/packages/plugin/src/index.ts
+++ b/packages/plugin/src/index.ts
@@ -192,10 +192,16 @@ export interface Hooks {
     },
   ) => Promise<void>
   /**
-   * Called before session compaction starts. Allows plugins to append
-   * additional context to the compaction prompt.
+   * Called before session compaction starts. Allows plugins to customize
+   * the compaction prompt.
+   *
+   * - `context`: Additional context strings appended to the default prompt
+   * - `prompt`: If set, replaces the default compaction prompt entirely
    */
-  "experimental.session.compacting"?: (input: { sessionID: string }, output: { context: string[] }) => Promise<void>
+  "experimental.session.compacting"?: (
+    input: { sessionID: string },
+    output: { context: string[]; prompt?: string },
+  ) => Promise<void>
   "experimental.text.complete"?: (
     input: { sessionID: string; messageID: string; partID: string },
     output: { text: string },