Fix MCP parameter rendering for arrays and objects in Claude logs (#13969)

* Initial plan

* Fix JavaScript rendering of Claude logs - handle array/object parameters

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

* Add test for ToolsSearch array rendering fix

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>
Co-authored-by: Peli de Halleux <pelikhan@users.noreply.github.com>

Author: Copilot

actions/setup/js/log_parser_shared.cjs

@@ -485,7 +485,30 @@ function formatMcpParameters(input) {
   const paramStrs = [];
   for (const key of keys.slice(0, 4)) {
     // Show up to 4 parameters
-    const value = String(input[key] || "");
+    const rawValue = input[key];
+    let value;
+
+    if (Array.isArray(rawValue)) {
+      // Format arrays as [item1, item2, ...]
+      if (rawValue.length === 0) {
+        value = "[]";
+      } else if (rawValue.length <= 3) {
+        // Show all items for small arrays
+        const items = rawValue.map(item => (typeof item === "object" && item !== null ? JSON.stringify(item) : String(item)));
+        value = `[${items.join(", ")}]`;
+      } else {
+        // Show first 2 items and count for larger arrays
+        const items = rawValue.slice(0, 2).map(item => (typeof item === "object" && item !== null ? JSON.stringify(item) : String(item)));
+        value = `[${items.join(", ")}, ...${rawValue.length - 2} more]`;
+      }
+    } else if (typeof rawValue === "object" && rawValue !== null) {
+      // Format objects as JSON
+      value = JSON.stringify(rawValue);
+    } else {
+      // Primitive values (string, number, boolean, null, undefined)
+      value = String(rawValue || "");
+    }
+
     paramStrs.push(`${key}: ${truncateString(value, 40)}`);
   }
 

actions/setup/js/log_parser_shared.test.cjs

@@ -539,6 +539,113 @@ describe("log_parser_shared.cjs", () => {
 
       expect(result).toBe("");
     });
+
+    it("should format array values correctly", async () => {
+      const { formatMcpParameters } = await import("./log_parser_shared.cjs");
+
+      const input = {
+        items: ["item1", "item2", "item3"],
+      };
+
+      const result = formatMcpParameters(input);
+
+      expect(result).toContain("items: [item1, item2, item3]");
+      expect(result).not.toContain("[object Object]");
+    });
+
+    it("should format small arrays (3 or fewer items)", async () => {
+      const { formatMcpParameters } = await import("./log_parser_shared.cjs");
+
+      const input = {
+        tags: ["tag1", "tag2"],
+      };
+
+      const result = formatMcpParameters(input);
+
+      expect(result).toBe("tags: [tag1, tag2]");
+    });
+
+    it("should format large arrays with ellipsis", async () => {
+      const { formatMcpParameters } = await import("./log_parser_shared.cjs");
+
+      const input = {
+        items: ["item1", "item2", "item3", "item4", "item5"],
+      };
+
+      const result = formatMcpParameters(input);
+
+      expect(result).toContain("items: [item1, item2, ...3 more]");
+    });
+
+    it("should format empty arrays", async () => {
+      const { formatMcpParameters } = await import("./log_parser_shared.cjs");
+
+      const input = {
+        emptyList: [],
+      };
+
+      const result = formatMcpParameters(input);
+
+      expect(result).toBe("emptyList: []");
+    });
+
+    it("should format object values as JSON", async () => {
+      const { formatMcpParameters } = await import("./log_parser_shared.cjs");
+
+      const input = {
+        config: { enabled: true, timeout: 30 },
+      };
+
+      const result = formatMcpParameters(input);
+
+      expect(result).toContain('config: {"enabled":true,"timeout":30}');
+      expect(result).not.toContain("[object Object]");
+    });
+
+    it("should format arrays containing objects", async () => {
+      const { formatMcpParameters } = await import("./log_parser_shared.cjs");
+
+      const input = {
+        tools: [{ name: "tool1" }, { name: "tool2" }],
+      };
+
+      const result = formatMcpParameters(input);
+
+      expect(result).toContain('tools: [{"name":"tool1"}, {"name":"tool2"}]');
+      expect(result).not.toContain("[object Object]");
+    });
+
+    it("should handle mixed parameter types", async () => {
+      const { formatMcpParameters } = await import("./log_parser_shared.cjs");
+
+      const input = {
+        query: "search term",
+        filters: ["filter1", "filter2"],
+        options: { caseSensitive: false },
+        limit: 10,
+      };
+
+      const result = formatMcpParameters(input);
+
+      expect(result).toContain("query: search term");
+      expect(result).toContain("filters: [filter1, filter2]");
+      expect(result).toContain('options: {"caseSensitive":false}');
+      expect(result).toContain("limit: 10");
+    });
+
+    it("should truncate long array representations", async () => {
+      const { formatMcpParameters } = await import("./log_parser_shared.cjs");
+
+      const input = {
+        longArray: ["a".repeat(50), "b".repeat(50)],
+      };
+
+      const result = formatMcpParameters(input);
+
+      // Should be truncated to 40 chars
+      expect(result.length).toBeLessThan(60);
+      expect(result).toContain("...");
+    });
   });
 
   describe("formatInitializationSummary", () => {

actions/setup/js/parse_claude_log.test.cjs

@@ -565,5 +565,51 @@ describe("parse_claude_log.cjs", () => {
       const toolsSection = result.markdown.split("## 🤖 Reasoning")[0];
       expect(toolsSection).not.toMatch(/and \d+ more/);
     });
+
+    it("should handle ToolsSearch with array of objects (issue fix)", () => {
+      const logWithToolsSearch = JSON.stringify([
+        {
+          type: "system",
+          subtype: "init",
+          session_id: "test-tools-search",
+          tools: ["Bash", "mcp__serena__ToolsSearch"],
+          model: "claude-sonnet-4-20250514",
+        },
+        {
+          type: "assistant",
+          message: {
+            content: [
+              {
+                type: "tool_use",
+                id: "tool_1",
+                name: "mcp__serena__ToolsSearch",
+                input: {
+                  query: "search term",
+                  tools: [
+                    { name: "tool1", type: "function" },
+                    { name: "tool2", type: "class" },
+                    { name: "tool3", type: "function" },
+                    { name: "tool4", type: "function" },
+                    { name: "tool5", type: "class" },
+                  ],
+                },
+              },
+            ],
+          },
+        },
+        { type: "result", total_cost_usd: 0.01, usage: { input_tokens: 100, output_tokens: 50 }, num_turns: 1 },
+      ]);
+      const result = parseClaudeLog(logWithToolsSearch);
+
+      // Should NOT contain [object Object] - the bug we're fixing
+      expect(result.markdown).not.toContain("[object Object]");
+
+      // Should contain properly formatted JSON array representation
+      expect(result.markdown).toContain("serena::ToolsSearch");
+      expect(result.markdown).toMatch(/tools:.*\[.*"name":"tool1"/);
+
+      // Should properly render the tool in initialization section
+      expect(result.markdown).toContain("serena::ToolsSearch");
+    });
   });
 });