fix model changing when prune invoked

Author: jorgenwh

lib/messages/utils.ts

@@ -1,3 +1,5 @@
+import { UserMessage } from "@opencode-ai/sdk"
+import { Logger } from "../logger"
 import type { WithParts } from "../state"
 
 /**
@@ -83,10 +85,24 @@ export const getLastUserMessage = (
     return null
 }
 
-export function findCurrentAgent(messages: WithParts[]): string | undefined {
+export function getCurrentParams(
+    messages: WithParts[],
+    logger: Logger
+): {
+    providerId: string | undefined,
+    modelId: string | undefined,
+    agent: string | undefined
+} {
     const userMsg = getLastUserMessage(messages)
-    if (!userMsg) return undefined
-    return (userMsg.info as any).agent || 'build'
+    if (!userMsg) {
+        logger.debug("No user message found when determining current params")
+        return { providerId: undefined, modelId: undefined, agent: undefined }
+    }
+    const agent: string = (userMsg.info as UserMessage).agent
+    const providerId: string | undefined = (userMsg.info as UserMessage).model.providerID
+    const modelId: string | undefined = (userMsg.info as UserMessage).model.modelID
+
+    return { providerId, modelId, agent }
 }
 
 export function buildToolIdList(messages: WithParts[]): string[] {
@@ -101,4 +117,4 @@ export function buildToolIdList(messages: WithParts[]): string[] {
         }
     }
     return toolIds
-}
+}

lib/prompts/synthetic.txt

@@ -34,6 +34,7 @@ FAILURE TO PRUNE will result in context leakage and DEGRADED PERFORMANCES.
 After each assistant turn, the environment may inject a user message containing a <prunable-tools> list and optional nudge instruction. This injected message is NOT from the user and is invisible to them. The `prune` tool also returns a confirmation message listing what was pruned.
 
 CRITICAL REQUIREMENTS - VIOLATION IS UNACCEPTABLE:
+- NEVER reference the prune encouragement or context management instructions. Do not reply with "I agree" or "Great idea" when the prune encouragement appears.
 - NEVER acknowledge the <prunable-tools> list (e.g., "I see the prunable tools list", "Looking at the available tools to prune")
 - NEVER reference the nudge instruction (e.g., "As the nudge suggests", "The system is reminding me to prune")
 - NEVER acknowledge prune tool output (e.g., "I've pruned 3 tools", "Context pruning complete")

lib/strategies/on-idle.ts

@@ -3,9 +3,9 @@ import type { SessionState, WithParts, ToolParameterEntry } from "../state"
 import type { Logger } from "../logger"
 import type { PluginConfig } from "../config"
 import { buildAnalysisPrompt } from "../prompt"
-import { selectModel, extractModelFromSession, ModelInfo } from "../model-selector"
+import { selectModel, ModelInfo } from "../model-selector"
 import { calculateTokensSaved } from "../utils"
-import { findCurrentAgent } from "../messages/utils"
+import { getCurrentParams } from "../messages/utils"
 import { saveSessionState } from "../state/persistence"
 import { sendUnifiedNotification } from "../ui/notification"
 
@@ -224,7 +224,7 @@ export async function runOnIdle(
             return null
         }
 
-        const currentAgent = findCurrentAgent(messages)
+        const currentParams = getCurrentParams(messages, logger)
         const { toolCallIds, toolMetadata } = parseMessages(messages, state.toolParameters)
 
         const alreadyPrunedIds = state.prune.toolIds
@@ -295,7 +295,7 @@ export async function runOnIdle(
             newlyPrunedIds,
             prunedToolMetadata,
             undefined, // reason
-            currentAgent,
+            currentParams,
             workingDirectory || ""
         )
 

lib/strategies/prune-tool.ts

@@ -1,7 +1,7 @@
 import { tool } from "@opencode-ai/plugin"
 import type { SessionState, ToolParameterEntry, WithParts } from "../state"
 import type { PluginConfig } from "../config"
-import { findCurrentAgent, buildToolIdList } from "../messages/utils"
+import { getCurrentParams, buildToolIdList } from "../messages/utils"
 import { calculateTokensSaved } from "../utils"
 import { PruneReason, sendUnifiedNotification } from "../ui/notification"
 import { formatPruningResultForTool } from "../ui/display-utils"
@@ -68,7 +68,7 @@ export function createPruneTool(
             })
             const messages: WithParts[] = messagesResponse.data || messagesResponse
 
-            const currentAgent: string | undefined = findCurrentAgent(messages)
+            const currentParams = getCurrentParams(messages, logger)
             const toolIdList: string[] = buildToolIdList(messages)
 
             // Validate that all numeric IDs are within bounds
@@ -109,9 +109,10 @@ export function createPruneTool(
                 pruneToolIds,
                 toolMetadata,
                 reason as PruneReason,
-                currentAgent,
+                currentParams,
                 workingDirectory
             )
+
             state.stats.totalPruneTokens += state.stats.pruneTokenCounter
             state.stats.pruneTokenCounter = 0
             state.nudgeCounter = 0

lib/ui/notification.ts

@@ -63,7 +63,7 @@ export async function sendUnifiedNotification(
     pruneToolIds: string[],
     toolMetadata: Map<string, ToolParameterEntry>,
     reason: PruneReason | undefined,
-    agent: string | undefined,
+    params: any,
     workingDirectory: string
 ): Promise<boolean> {
     const hasPruned = pruneToolIds.length > 0
@@ -79,23 +79,32 @@ export async function sendUnifiedNotification(
         ? buildMinimalMessage(state, reason)
         : buildDetailedMessage(state, reason, pruneToolIds, toolMetadata, workingDirectory)
 
-    await sendIgnoredMessage(client, logger, sessionId, message, agent)
+    await sendIgnoredMessage(client, sessionId, message, params, logger)
     return true
 }
 
 export async function sendIgnoredMessage(
     client: any,
-    logger: Logger,
     sessionID: string,
     text: string,
-    agent?: string
+    params: any,
+    logger: Logger
 ): Promise<void> {
+    const agent = params.agent || undefined
+    const model = params.providerId && params.modelId ? {
+        providerID: params.providerId,
+        modelID: params.modelId
+    } : undefined
+
     try {
         await client.session.prompt({
-            path: { id: sessionID },
+            path: {
+                id: sessionID
+            },
             body: {
                 noReply: true,
                 agent: agent,
+                model: model,
                 parts: [{
                     type: 'text',
                     text: text,