core: add configurable compaction settings to allow users to disable auto-compaction and pruning via config instead of flags

packages/opencode/src/config/config.ts

@@ -141,6 +141,14 @@ export namespace Config {
 
     if (!result.keybinds) result.keybinds = Info.shape.keybinds.parse({})
 
+    // Apply flag overrides for compaction settings
+    if (Flag.OPENCODE_DISABLE_AUTOCOMPACT) {
+      result.compaction = { ...result.compaction, auto: false }
+    }
+    if (Flag.OPENCODE_DISABLE_PRUNE) {
+      result.compaction = { ...result.compaction, prune: false }
+    }
+
     return {
       config: result,
       directories,
@@ -791,6 +799,12 @@ export namespace Config {
           url: z.string().optional().describe("Enterprise URL"),
         })
         .optional(),
+      compaction: z
+        .object({
+          auto: z.boolean().optional().describe("Enable automatic compaction when context is full (default: true)"),
+          prune: z.boolean().optional().describe("Enable pruning of old tool outputs (default: true)"),
+        })
+        .optional(),
       experimental: z
         .object({
           hook: z

packages/opencode/src/session/compaction.ts

@@ -7,13 +7,13 @@ import { Provider } from "../provider/provider"
 import { MessageV2 } from "./message-v2"
 import z from "zod"
 import { SessionPrompt } from "./prompt"
-import { Flag } from "../flag/flag"
 import { Token } from "../util/token"
 import { Log } from "../util/log"
 import { SessionProcessor } from "./processor"
 import { fn } from "@/util/fn"
 import { Agent } from "@/agent/agent"
 import { Plugin } from "@/plugin"
+import { Config } from "@/config/config"
 
 export namespace SessionCompaction {
   const log = Log.create({ service: "session.compaction" })
@@ -27,8 +27,9 @@ export namespace SessionCompaction {
     ),
   }
 
-  export function isOverflow(input: { tokens: MessageV2.Assistant["tokens"]; model: Provider.Model }) {
-    if (Flag.OPENCODE_DISABLE_AUTOCOMPACT) return false
+  export async function isOverflow(input: { tokens: MessageV2.Assistant["tokens"]; model: Provider.Model }) {
+    const config = await Config.get()
+    if ((config.compaction?.auto ?? true) === false) return false
     const context = input.model.limit.context
     if (context === 0) return false
     const count = input.tokens.input + input.tokens.cache.read + input.tokens.output
@@ -46,7 +47,8 @@ export namespace SessionCompaction {
   // calls. then erases output of previous tool calls. idea is to throw away old
   // tool calls that are no longer relevant.
   export async function prune(input: { sessionID: string }) {
-    if (Flag.OPENCODE_DISABLE_PRUNE) return
+    const config = await Config.get()
+    if ((config.compaction?.prune ?? true) === false) return
     log.info("pruning")
     const msgs = await Session.messages({ sessionID: input.sessionID })
     let total = 0

packages/opencode/src/session/prompt.ts

@@ -459,7 +459,7 @@ export namespace SessionPrompt {
       if (
         lastFinished &&
         lastFinished.summary !== true &&
-        SessionCompaction.isOverflow({ tokens: lastFinished.tokens, model })
+        (await SessionCompaction.isOverflow({ tokens: lastFinished.tokens, model }))
       ) {
         await SessionCompaction.create({
           sessionID,