Merge pull request #3 from Grigory-Rylov/fix/system_prompt_lang

fix(core, opencode): add language consistency instructions to synthetic messages

Author: Grigory-Rylov

packages/core/src/session/runner/to-llm-message.ts

@@ -137,7 +137,9 @@ ${message.summary}
 <recent-context>
 ${message.recent}
 </recent-context>
-</conversation-checkpoint>`,
+</conversation-checkpoint>
+
+Continue responding in the same language as the conversation.`,
           metadata: message.metadata,
         }),
       ]

packages/opencode/src/session/compaction.ts

@@ -504,7 +504,7 @@ export const layer = Layer.effect(
               (input.overflow
                 ? "The previous request exceeded the provider's size limit due to large media attachments. The conversation was compacted and media files were removed from context. If the user was asking about attached images or files, explain that the attachments were too large to process and suggest they try again with smaller or fewer files.\n\n"
                 : "") +
-              "Continue if you have next steps, or stop and ask for clarification if you are unsure how to proceed."
+              "Continue if you have next steps, or stop and ask for clarification if you are unsure how to proceed. Respond in the same language as the conversation."
             yield* session.updatePart({
               id: PartID.ascending(),
               messageID: continueMsg.id,

packages/opencode/src/session/message-v2.ts

@@ -239,13 +239,13 @@ export const toModelMessagesEffect = Effect.fnUntraced(function* (
         if (part.type === "compaction") {
           userMessage.parts.push({
             type: "text",
-            text: "What did we do so far?",
+            text: "What did we do so far? Respond in the same language as the conversation.",
           })
         }
         if (part.type === "subtask") {
           userMessage.parts.push({
             type: "text",
-            text: "The following tool was executed by the user",
+            text: "The following tool was executed by the user. Continue in the same language as the conversation.",
           })
         }
       }

packages/opencode/src/session/prompt.ts

@@ -427,7 +427,7 @@ export const layer = Layer.effect(
         messageID: summaryUserMsg.id,
         sessionID,
         type: "text",
-        text: "Summarize the task tool output above and continue with your task.",
+        text: "Summarize the task tool output above and continue with your task. Respond in the same language as the conversation.",
         synthetic: true,
       } satisfies SessionV1.TextPart)
     })
@@ -465,7 +465,7 @@ export const layer = Layer.effect(
               id: PartID.ascending(),
               messageID: userMsg.id,
               sessionID: input.sessionID,
-              text: "The following tool was executed by the user",
+              text: "The following tool was executed by the user. Continue in the same language as the conversation.",
               synthetic: true,
             }
             yield* sessions.updatePart(userPart)
@@ -1315,7 +1315,7 @@ export const layer = Layer.effect(
                     "The user sent the following message:",
                     p.text,
                     "",
-                    "Please address this message and continue with your tasks.",
+                    "Please address this message and continue with your tasks. Respond in the same language as the user's message.",
                     "</system-reminder>",
                   ].join("\n")
                 }