Merge pull request #149 from Opencode-DCP/fix-model-changing-when-prune-invoked

When sending the ignored notification message for the prune results using the SDK API the model would automatically reset to whatever model is configured for the current agent mode.

This PR fixes this issue by storing which provider and model is used as well as agent mode, and when we send the notification message we ensure all of these params persist.

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,