diff --git a/packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx b/packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx
index 99a90ab46ac..8fefcb20394 100644
--- a/packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx
+++ b/packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx
@@ -509,6 +509,14 @@ export function Prompt(props: PromptProps) {
         command: inputText,
       })
       setStore("mode", "normal")
+    } else if (inputText.match(/^\/(compact|summarize)(\s|$)/)) {
+      const args = inputText.replace(/^\/(compact|summarize)\s*/, "")
+      sdk.client.session.summarize({
+        sessionID,
+        modelID: selectedModel.modelID,
+        providerID: selectedModel.providerID,
+        args: args || undefined,
+      })
     } else if (
       inputText.startsWith("/") &&
       iife(() => {
diff --git a/packages/opencode/src/server/server.ts b/packages/opencode/src/server/server.ts
index 8957228ad41..21826865f87 100644
--- a/packages/opencode/src/server/server.ts
+++ b/packages/opencode/src/server/server.ts
@@ -1054,6 +1054,7 @@ export namespace Server {
           z.object({
             providerID: z.string(),
             modelID: z.string(),
+            args: z.string().optional(),
           }),
         ),
         async (c) => {
@@ -1076,6 +1077,7 @@ export namespace Server {
               modelID: body.modelID,
             },
             auto: false,
+            args: body.args,
           })
           await SessionPrompt.loop(sessionID)
           return c.json(true)
diff --git a/packages/opencode/src/session/compaction.ts b/packages/opencode/src/session/compaction.ts
index 3e4c8020dee..29e475f4e9a 100644
--- a/packages/opencode/src/session/compaction.ts
+++ b/packages/opencode/src/session/compaction.ts
@@ -91,6 +91,9 @@ export namespace SessionCompaction {
     auto: boolean
   }) {
     const userMessage = input.messages.findLast((m) => m.info.id === input.parentID)!.info as MessageV2.User
+    const compactionPart = input.messages
+      .findLast((m) => m.info.id === input.parentID)!
+      .parts.find((p): p is MessageV2.CompactionPart => p.type === "compaction")
     const agent = await Agent.get("compaction")
     const model = agent.model
       ? await Provider.getModel(agent.model.providerID, agent.model.modelID)
@@ -129,7 +132,7 @@ export namespace SessionCompaction {
     // Allow plugins to inject context for compaction
     const compacting = await Plugin.trigger(
       "experimental.session.compacting",
-      { sessionID: input.sessionID },
+      { sessionID: input.sessionID, args: compactionPart?.args },
       { context: [] },
     )
     const result = await processor.process({
@@ -195,6 +198,7 @@ export namespace SessionCompaction {
         modelID: z.string(),
       }),
       auto: z.boolean(),
+      args: z.string().optional(),
     }),
     async (input) => {
       const msg = await Session.updateMessage({
@@ -213,6 +217,7 @@ export namespace SessionCompaction {
         sessionID: msg.sessionID,
         type: "compaction",
         auto: input.auto,
+        args: input.args,
       })
     },
   )
diff --git a/packages/opencode/src/session/message-v2.ts b/packages/opencode/src/session/message-v2.ts
index 4781b0c47b1..76b685674e7 100644
--- a/packages/opencode/src/session/message-v2.ts
+++ b/packages/opencode/src/session/message-v2.ts
@@ -150,6 +150,7 @@ export namespace MessageV2 {
   export const CompactionPart = PartBase.extend({
     type: z.literal("compaction"),
     auto: z.boolean(),
+    args: z.string().optional(),
   }).meta({
     ref: "CompactionPart",
   })
diff --git a/packages/plugin/src/index.ts b/packages/plugin/src/index.ts
index 487e6ed3ee2..d6c365d05da 100644
--- a/packages/plugin/src/index.ts
+++ b/packages/plugin/src/index.ts
@@ -195,7 +195,10 @@ export interface Hooks {
    * Called before session compaction starts. Allows plugins to append
    * additional context to the compaction prompt.
    */
-  "experimental.session.compacting"?: (input: { sessionID: string }, output: { context: string[] }) => Promise<void>
+  "experimental.session.compacting"?: (
+    input: { sessionID: string; args?: string },
+    output: { context: string[] },
+  ) => Promise<void>
   "experimental.text.complete"?: (
     input: { sessionID: string; messageID: string; partID: string },
     output: { text: string },
diff --git a/packages/sdk/js/src/v2/gen/sdk.gen.ts b/packages/sdk/js/src/v2/gen/sdk.gen.ts
index 16fe07ae4a8..d935bf811dc 100644
--- a/packages/sdk/js/src/v2/gen/sdk.gen.ts
+++ b/packages/sdk/js/src/v2/gen/sdk.gen.ts
@@ -1127,6 +1127,7 @@ export class Session extends HeyApiClient {
       directory?: string
       providerID?: string
       modelID?: string
+      args?: string
     },
     options?: Options<never, ThrowOnError>,
   ) {
@@ -1139,6 +1140,7 @@ export class Session extends HeyApiClient {
             { in: "query", key: "directory" },
             { in: "body", key: "providerID" },
             { in: "body", key: "modelID" },
+            { in: "body", key: "args" },
           ],
         },
       ],
diff --git a/packages/sdk/js/src/v2/gen/types.gen.ts b/packages/sdk/js/src/v2/gen/types.gen.ts
index 00f209c6d88..242388c26ce 100644
--- a/packages/sdk/js/src/v2/gen/types.gen.ts
+++ b/packages/sdk/js/src/v2/gen/types.gen.ts
@@ -405,6 +405,7 @@ export type CompactionPart = {
   messageID: string
   type: "compaction"
   auto: boolean
+  args?: string
 }
 
 export type Part =
@@ -2733,6 +2734,7 @@ export type SessionSummarizeData = {
   body?: {
     providerID: string
     modelID: string
+    args?: string
   }
   path: {
     /**