fix: sanitize Read tool args to prevent retry loops from non-Anthropic models (#1144)

* fix: sanitize Read tool args to prevent retry loops from non-Anthropic models

* fix: sanitize invalid Read pages from tool args

Non-Anthropic models sometimes emit optional Read args like pages: "" for
non-PDF files, which Claude Code rejects before the tool runs. Drop invalid
pages values, keep valid PDF page ranges, and coerce numeric string bounds
before clamping limit/offset.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/unit/openai-to-claude-response-tools.test.js

@@ -0,0 +1,61 @@
+import { describe, expect, it } from "vitest";
+import { openaiToClaudeResponse } from "../../open-sse/translator/response/openai-to-claude.js";
+
+function createState() {
+  return { toolCalls: new Map(), nextBlockIndex: 0 };
+}
+
+function getInputJsonDelta(events) {
+  return events.find((event) => event.type === "content_block_delta" && event.delta?.type === "input_json_delta")?.delta.partial_json;
+}
+
+describe("openaiToClaudeResponse tool argument sanitization", () => {
+  it("drops invalid Read pages and clamps numeric bounds", () => {
+    const state = createState();
+
+    openaiToClaudeResponse({
+      id: "chatcmpl-test-read",
+      model: "test-model",
+      choices: [{ delta: { tool_calls: [{ index: 0, id: "toolu_read", function: { name: "Read" } }] } }],
+    }, state);
+
+    const events = openaiToClaudeResponse({
+      id: "chatcmpl-test-read",
+      model: "test-model",
+      choices: [{
+        delta: { tool_calls: [{ index: 0, function: { arguments: JSON.stringify({ file_path: "F:/repo/file.js", offset: -5, limit: 999999999, pages: "" }) } }] },
+        finish_reason: "tool_calls",
+      }],
+    }, state);
+
+    expect(JSON.parse(getInputJsonDelta(events))).toEqual({
+      file_path: "F:/repo/file.js",
+      offset: 0,
+      limit: 2000,
+    });
+  });
+
+  it("keeps valid PDF pages", () => {
+    const state = createState();
+
+    openaiToClaudeResponse({
+      id: "chatcmpl-test-pdf",
+      model: "test-model",
+      choices: [{ delta: { tool_calls: [{ index: 0, id: "toolu_pdf", function: { name: "proxy_Read" } }] } }],
+    }, state);
+
+    const events = openaiToClaudeResponse({
+      id: "chatcmpl-test-pdf",
+      model: "test-model",
+      choices: [{
+        delta: { tool_calls: [{ index: 0, function: { arguments: JSON.stringify({ file_path: "F:/repo/doc.pdf", pages: "1-3" }) } }] },
+        finish_reason: "tool_calls",
+      }],
+    }, state);
+
+    expect(JSON.parse(getInputJsonDelta(events))).toEqual({
+      file_path: "F:/repo/doc.pdf",
+      pages: "1-3",
+    });
+  });
+});