fix(agents): sanitize transcripts for strict tool APIs

src/agents/pi-extensions/transcript-sanitize.ts

@@ -0,0 +1,35 @@
+/**
+ * Transcript repair/sanitization extension.
+ *
+ * Runs on every context build to prevent strict provider request rejections:
+ * - duplicate or displaced tool results (Anthropic-compatible APIs, MiniMax, Cloud Code Assist)
+ * - Cloud Code Assist tool call ID constraints + collision-safe sanitization
+ */
+
+import type { AgentMessage } from "@mariozechner/pi-agent-core";
+import type {
+  ContextEvent,
+  ExtensionAPI,
+  ExtensionContext,
+} from "@mariozechner/pi-coding-agent";
+
+import { isGoogleModelApi } from "../pi-embedded-helpers.js";
+import { sanitizeToolUseResultPairing } from "../session-transcript-repair.js";
+import { sanitizeToolCallIdsForCloudCodeAssist } from "../tool-call-id.js";
+
+export default function transcriptSanitizeExtension(api: ExtensionAPI): void {
+  api.on("context", (event: ContextEvent, ctx: ExtensionContext) => {
+    let next = event.messages as AgentMessage[];
+
+    const repairedTools = sanitizeToolUseResultPairing(next);
+    if (repairedTools !== next) next = repairedTools;
+
+    if (isGoogleModelApi(ctx.model?.api)) {
+      const repairedIds = sanitizeToolCallIdsForCloudCodeAssist(next);
+      if (repairedIds !== next) next = repairedIds;
+    }
+
+    if (next === event.messages) return undefined;
+    return { messages: next };
+  });
+}