fix(lsp): accept directory as alias for filePath in lsp_diagnostics

Models frequently hallucinate a 'directory' parameter alongside filePath,
causing hard failures. Instead of rejecting, accept directory as an alias
for filePath and gracefully handle when both are provided (prefer filePath).

This prevents the 'filePath and directory are mutually exclusive' error
that users hit when models pass both parameters.

Fixes model confusion with lsp_diagnostics tool parameters.

src/tools/lsp/diagnostics-tool.ts

@@ -10,9 +10,16 @@ import type { Diagnostic } from "./types"
 
 export const lsp_diagnostics: ToolDefinition = tool({
   description:
-    'Get errors, warnings, hints from language server BEFORE running build. For directories, provide \'extension\' parameter (e.g., extension=".ts").',
+    'Get errors, warnings, hints from language server BEFORE running build. Use filePath for a single file, or filePath with extension for a directory. Do NOT pass both filePath and directory — use filePath for everything.',
   args: {
-    filePath: tool.schema.string(),
+    filePath: tool.schema
+      .string()
+      .optional()
+      .describe("File or directory path to check diagnostics for"),
+    directory: tool.schema
+      .string()
+      .optional()
+      .describe("Alias for filePath when checking a directory. Do NOT provide both filePath and directory."),
     severity: tool.schema
       .enum(["error", "warning", "information", "hint", "all"])
       .optional()
@@ -20,11 +27,20 @@ export const lsp_diagnostics: ToolDefinition = tool({
     extension: tool.schema
       .string()
       .optional()
-      .describe("Required if filePath is a directory. E.g., '.ts', '.py', '.go'"),
+      .describe("Required if target is a directory. E.g., '.ts', '.py', '.go', '.java'"),
   },
   execute: async (args, _context) => {
     try {
-      const absPath = resolve(args.filePath)
+      // Accept either filePath or directory (treat directory as alias for filePath)
+      const targetPath = args.filePath || args.directory
+      if (!targetPath) {
+        throw new Error("Provide either 'filePath' or 'directory' parameter.")
+      }
+      if (args.filePath && args.directory) {
+        // Instead of erroring, just use filePath and ignore directory
+        // This prevents model confusion from causing hard failures
+      }
+      const absPath = resolve(targetPath)
 
       if (isDirectoryPath(absPath)) {
         if (!args.extension) {
@@ -37,8 +53,8 @@ export const lsp_diagnostics: ToolDefinition = tool({
         return await aggregateDiagnosticsForDirectory(absPath, args.extension, args.severity)
       }
 
-      const result = await withLspClient(args.filePath, async (client) => {
-        return (await client.diagnostics(args.filePath)) as { items?: Diagnostic[] } | Diagnostic[] | null
+      const result = await withLspClient(targetPath, async (client) => {
+        return (await client.diagnostics(targetPath)) as { items?: Diagnostic[] } | Diagnostic[] | null
       })
 
       let diagnostics: Diagnostic[] = []