feat(lsp): add directory support to lsp_diagnostics via extension param

- Add isDirectoryPath helper to lsp-client-wrapper.ts
- Create directory-diagnostics.ts with aggregateDiagnosticsForDirectory
- Update diagnostics-tool.ts with extension parameter for directory paths
- Update Atlas agent prompts to use extension param for directory diagnostics
- Add unit tests for isDirectoryPath and aggregateDiagnosticsForDirectory

Fixes #2362

bun.lock

@@ -29,17 +29,17 @@
         "typescript": "^5.7.3",
       },
       "optionalDependencies": {
-        "oh-my-opencode-darwin-arm64": "3.10.0",
-        "oh-my-opencode-darwin-x64": "3.10.0",
-        "oh-my-opencode-darwin-x64-baseline": "3.10.0",
-        "oh-my-opencode-linux-arm64": "3.10.0",
-        "oh-my-opencode-linux-arm64-musl": "3.10.0",
-        "oh-my-opencode-linux-x64": "3.10.0",
-        "oh-my-opencode-linux-x64-baseline": "3.10.0",
-        "oh-my-opencode-linux-x64-musl": "3.10.0",
-        "oh-my-opencode-linux-x64-musl-baseline": "3.10.0",
-        "oh-my-opencode-windows-x64": "3.10.0",
-        "oh-my-opencode-windows-x64-baseline": "3.10.0",
+        "oh-my-opencode-darwin-arm64": "3.11.0",
+        "oh-my-opencode-darwin-x64": "3.11.0",
+        "oh-my-opencode-darwin-x64-baseline": "3.11.0",
+        "oh-my-opencode-linux-arm64": "3.11.0",
+        "oh-my-opencode-linux-arm64-musl": "3.11.0",
+        "oh-my-opencode-linux-x64": "3.11.0",
+        "oh-my-opencode-linux-x64-baseline": "3.11.0",
+        "oh-my-opencode-linux-x64-musl": "3.11.0",
+        "oh-my-opencode-linux-x64-musl-baseline": "3.11.0",
+        "oh-my-opencode-windows-x64": "3.11.0",
+        "oh-my-opencode-windows-x64-baseline": "3.11.0",
       },
     },
   },
@@ -238,27 +238,27 @@
 
     "object-inspect": ["object-inspect@1.13.4", "", {}, "sha512-W67iLl4J2EXEGTbfeHCffrjDfitvLANg0UlX3wFUUSTx92KXRFegMHUVgSqE+wvhAbi4WqjGg9czysTV2Epbew=="],
 
-    "oh-my-opencode-darwin-arm64": ["oh-my-opencode-darwin-arm64@3.10.0", "", { "os": "darwin", "cpu": "arm64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-KQ1Nva4eU03WIaQI8BiEgizYJAeddUIaC8dmks0Ug/2EkH6VyNj41+shI58HFGN9Jlg9Fd6MxpOW92S3JUHjOw=="],
+    "oh-my-opencode-darwin-arm64": ["oh-my-opencode-darwin-arm64@3.11.0", "", { "os": "darwin", "cpu": "arm64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-TLMCq1HXU1BOp3KWdcITQqT3TQcycAxvdYELMzY/17HUVHjvJiaLjyrbmw0VlgBjoRZOlmsedK+o59y7WRM40Q=="],
 
-    "oh-my-opencode-darwin-x64": ["oh-my-opencode-darwin-x64@3.10.0", "", { "os": "darwin", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-PydZ6wKyLZzikSZA3Q89zKZwFyg0Ouqd/S6zDsf1zzpUWT1t5EcpBtYFwuscD7L4hdkIEFm8wxnnBkz5i6BEiA=="],
+    "oh-my-opencode-darwin-x64": ["oh-my-opencode-darwin-x64@3.11.0", "", { "os": "darwin", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-szKfyAYbI3Mp6rqxHxcHhAE8noxIzBbpfvKX0acyMB/KRqUCtgTe13aic5tz/W/Agp9NU1PVasyqjJjAtE73JA=="],
 
-    "oh-my-opencode-darwin-x64-baseline": ["oh-my-opencode-darwin-x64-baseline@3.10.0", "", { "os": "darwin", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-yOaVd0E1qspT2xP/BMJaJ/rpFTwkOh9U/SAk6uOuxHld6dZGI9e2Oq8F3pSD16xHnnpaz4VzadtT6HkvPdtBYg=="],
+    "oh-my-opencode-darwin-x64-baseline": ["oh-my-opencode-darwin-x64-baseline@3.11.0", "", { "os": "darwin", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-QZ+2LCcXK6NPopYSxFCHrYAqLccN+jMQ0YrQI+QBlsajLSsnSqfv6W3Vaxv95iLWhGey3v2oGu5OUgdW9fjy9w=="],
 
-    "oh-my-opencode-linux-arm64": ["oh-my-opencode-linux-arm64@3.10.0", "", { "os": "linux", "cpu": "arm64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-pLzcPMuzBb1tpVgqMilv7QdsE2xTMLCWT3b807mzjt0302fZTfm6emwymCG25RamHdq7+mI2B0rN7hjvbymFog=="],
+    "oh-my-opencode-linux-arm64": ["oh-my-opencode-linux-arm64@3.11.0", "", { "os": "linux", "cpu": "arm64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-NZMbNG+kJ0FTS4u5xhuBUjJ2K2Tds8sETbdq1VPT52rd+mIbVVSbugfppagEh9wbNqXqJY1HwQ/+4Q+NoGGXhQ=="],
 
-    "oh-my-opencode-linux-arm64-musl": ["oh-my-opencode-linux-arm64-musl@3.10.0", "", { "os": "linux", "cpu": "arm64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-ca61zr+X8q0ipO2x72qU+4R6Dsr168OM9aXI6xDHbrr0l3XZlRO8xuwQidch1vE5QRv2/IJT10KjAFInCERDug=="],
+    "oh-my-opencode-linux-arm64-musl": ["oh-my-opencode-linux-arm64-musl@3.11.0", "", { "os": "linux", "cpu": "arm64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-f0GO63uAwzBisotiMneA7Pi2xPXUxvdX5QRC6z4X2xoB8F7/jT+2+dY8J03eM+YJVAwQWR/74hm5HFSenqMeIA=="],
 
-    "oh-my-opencode-linux-x64": ["oh-my-opencode-linux-x64@3.10.0", "", { "os": "linux", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-m0Ys8Vnl8jUNRE5/aIseNOF1H57/W77xh3vkyBVfnjzHwQdEUWZz3IdoHaEWIFgIP2+fsNXRHqpx7Pbtuhxo6Q=="],
+    "oh-my-opencode-linux-x64": ["oh-my-opencode-linux-x64@3.11.0", "", { "os": "linux", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-OzIgo26t1EbooHwzmli+4aemO6YqXEhJTBth8L688K1CI/xF567G3+uJemZ9U7NI+miHJRoKHcidNnaAi7bgGQ=="],
 
-    "oh-my-opencode-linux-x64-baseline": ["oh-my-opencode-linux-x64-baseline@3.10.0", "", { "os": "linux", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-a6OhfqMXhOTq1On8YHRRlVsNtMx84kgNAnStk/sY1Dw0kXU68QK4tWXVF+wNdiRG3egeM2SvjhJ5RhWlr3CCNQ=="],
+    "oh-my-opencode-linux-x64-baseline": ["oh-my-opencode-linux-x64-baseline@3.11.0", "", { "os": "linux", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-ac7TfBli+gaHVu4aBtP2ADWzetrFZOs+h1K39KsR6MOhDZBl+B6B1S47U+BXGWtUKIRYm4uUo578XdnmsDanoA=="],
 
-    "oh-my-opencode-linux-x64-musl": ["oh-my-opencode-linux-x64-musl@3.10.0", "", { "os": "linux", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-lZkoEWwmrlVoZKewHNslUmQ2D6eWi1YqsoZMTd3qRj8V4XI6TDZHxg86hw4oxZ/EnKO4un+r83tb09JAAb1nNQ=="],
+    "oh-my-opencode-linux-x64-musl": ["oh-my-opencode-linux-x64-musl@3.11.0", "", { "os": "linux", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-OvOsPNuvZQug4tGjbcpbvh67tud1K84A3Qskt9S7BHBIvMH129iV/2GGyr6aca8gwvd5T+X05H/s5mnPG6jkBQ=="],
 
-    "oh-my-opencode-linux-x64-musl-baseline": ["oh-my-opencode-linux-x64-musl-baseline@3.10.0", "", { "os": "linux", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-UqArUpatMuen8+hZhMSbScaSmJlcwkEtf/IzDN1iYO0CttvhyYMUmm3el/1gWTAcaGNDFNkGmTli5WNYhnm2lA=="],
+    "oh-my-opencode-linux-x64-musl-baseline": ["oh-my-opencode-linux-x64-musl-baseline@3.11.0", "", { "os": "linux", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode" } }, "sha512-fSsyVAFMoOljD+zqRO6lG3f9ka1YRLMp6rNSsPWkLEKKIyEdw1J0GcmA/48VI1NgtnEgKqS3Ft87tees1woyBw=="],
 
-    "oh-my-opencode-windows-x64": ["oh-my-opencode-windows-x64@3.10.0", "", { "os": "win32", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode.exe" } }, "sha512-BivOu1+Yty9N6VSmNzmxROZqjQKu3ImWjooKZDfczvYLDQmZV104QcOKV6bmdOCpHrqQ7cvdbygmeiJeRoYShg=="],
+    "oh-my-opencode-windows-x64": ["oh-my-opencode-windows-x64@3.11.0", "", { "os": "win32", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode.exe" } }, "sha512-k9F3/9r3pFnUVJW36+zF06znUdUzcnJp+BdvDcaJrcuuM516ECwCH0yY5WbDTFFydFBQBkPBJX9DwU8dmc4kHA=="],
 
-    "oh-my-opencode-windows-x64-baseline": ["oh-my-opencode-windows-x64-baseline@3.10.0", "", { "os": "win32", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode.exe" } }, "sha512-BBv+dNPuh9LEuqXUJLXNsvi3vL30zS1qcJuzlq/s8rYHry+VvEVXCRcMm5Vo0CVna8bUZf5U8MDkGDHOAiTeEw=="],
+    "oh-my-opencode-windows-x64-baseline": ["oh-my-opencode-windows-x64-baseline@3.11.0", "", { "os": "win32", "cpu": "x64", "bin": { "oh-my-opencode": "bin/oh-my-opencode.exe" } }, "sha512-mRRcCHC43TLUuIkDs0ASAUGo3DpMIkSeIPDdtBrh1eJZyVulJRGBoniIk/+Y+RJwtsUoC+lUX/auQelzJsMpbQ=="],
 
     "on-finished": ["on-finished@2.4.1", "", { "dependencies": { "ee-first": "1.1.1" } }, "sha512-oVlzkg3ENAhCk2zdv7IJwd/QUD4z2RxRwpkcGY8psCVcCYZNq4wYnVWALHM+brtuJjePWiYF/ClmuDr8Ch5+kg=="],
 

src/agents/atlas/default.ts

@@ -184,7 +184,7 @@ task(
 After EVERY delegation, complete ALL of these steps — no shortcuts:
 
 #### A. Automated Verification
-1. \`lsp_diagnostics(filePath=".")\` → ZERO errors at project level
+1. 'lsp_diagnostics(filePath=".", extension=".ts")' → ZERO errors at project level (for directory paths, extension parameter is required)
 2. \`bun run build\` or \`bun run typecheck\` → exit code 0
 3. \`bun test\` → ALL tests pass
 
@@ -346,7 +346,7 @@ You are the QA gate. Subagents lie. Verify EVERYTHING.
 
 **After each delegation — BOTH automated AND manual verification are MANDATORY:**
 
-1. \`lsp_diagnostics\` at PROJECT level → ZERO errors
+1. 'lsp_diagnostics(filePath=".", extension=".ts")' at PROJECT level → ZERO errors (for directory paths, extension parameter is required)
 2. Run build command → exit 0
 3. Run test suite → ALL pass
 4. **\`Read\` EVERY changed file line by line** → logic matches requirements
@@ -390,7 +390,7 @@ You are the QA gate. Subagents lie. Verify EVERYTHING.
 - Trust subagent claims without verification
 - Use run_in_background=true for task execution
 - Send prompts under 30 lines
-- Skip project-level lsp_diagnostics after delegation
+- Skip project-level lsp_diagnostics after delegation (use 'filePath=".", extension=".ts"' for TypeScript projects)
 - Batch multiple tasks in one delegation
 - Start fresh session for failures/follow-ups - use \`resume\` instead
 

src/agents/atlas/gemini.ts

@@ -361,7 +361,7 @@ Subagents CLAIM "done" when:
 - Trust subagent claims without verification
 - Use run_in_background=true for task execution
 - Send prompts under 30 lines
-- Skip project-level lsp_diagnostics
+- Skip project-level lsp_diagnostics (use 'filePath=".", extension=".ts"' for TypeScript projects)
 - Batch multiple tasks in one delegation
 - Start fresh session for failures (use session_id)
 

src/agents/atlas/gpt.ts

@@ -55,7 +55,7 @@ Implementation tasks are the means. Final Wave approval is the goal.
   - Verification (use Bash for tests/build)
 - Parallelize independent tool calls when possible.
 - After ANY delegation, verify with your own tool calls:
-  1. \`lsp_diagnostics\` at project level
+  1. 'lsp_diagnostics(filePath=".", extension=".ts")' at project level (for directory paths, extension parameter is required)
   2. \`Bash\` for build/test commands
   3. \`Read\` for changed files
 </tool_usage_rules>
@@ -364,7 +364,7 @@ Your job is to CATCH THEM. Assume every claim is false until YOU personally veri
 - Trust subagent claims without verification
 - Use run_in_background=true for task execution
 - Send prompts under 30 lines
-- Skip project-level lsp_diagnostics
+- Skip project-level lsp_diagnostics (use 'filePath=".", extension=".ts"' for TypeScript projects)
 - Batch multiple tasks in one delegation
 - Start fresh session for failures (use session_id)
 

src/tools/lsp/constants.ts

@@ -1,6 +1,7 @@
 export const DEFAULT_MAX_REFERENCES = 200
 export const DEFAULT_MAX_SYMBOLS = 200
 export const DEFAULT_MAX_DIAGNOSTICS = 200
+export const DEFAULT_MAX_DIRECTORY_FILES = 50
 
 export { SYMBOL_KIND_MAP, SEVERITY_MAP, EXT_TO_LANG } from "./language-mappings"
 export { BUILTIN_SERVERS, LSP_INSTALL_HINTS } from "./server-definitions"

src/tools/lsp/diagnostics-tool.ts

@@ -1,21 +1,42 @@
+import { resolve } from "path"
+
 import { tool, type ToolDefinition } from "@opencode-ai/plugin/tool"
 
 import { DEFAULT_MAX_DIAGNOSTICS } from "./constants"
+import { aggregateDiagnosticsForDirectory } from "./directory-diagnostics"
 import { filterDiagnosticsBySeverity, formatDiagnostic } from "./lsp-formatters"
-import { withLspClient } from "./lsp-client-wrapper"
+import { isDirectoryPath, withLspClient } from "./lsp-client-wrapper"
 import type { Diagnostic } from "./types"
 
 export const lsp_diagnostics: ToolDefinition = tool({
-  description: "Get errors, warnings, hints from language server BEFORE running build.",
+  description:
+    'Get errors, warnings, hints from language server BEFORE running build. For directories, provide \'extension\' parameter (e.g., extension=".ts").',
   args: {
     filePath: tool.schema.string(),
     severity: tool.schema
       .enum(["error", "warning", "information", "hint", "all"])
       .optional()
       .describe("Filter by severity level"),
+    extension: tool.schema
+      .string()
+      .optional()
+      .describe("Required if filePath is a directory. E.g., '.ts', '.py', '.go'"),
   },
   execute: async (args, _context) => {
     try {
+      const absPath = resolve(args.filePath)
+
+      if (isDirectoryPath(absPath)) {
+        if (!args.extension) {
+          throw new Error(
+            `Directory path requires 'extension' parameter.\n\n` +
+              `Example: lsp_diagnostics(filePath="src", extension=".ts")\n\n` +
+              `Supported extensions: .ts, .tsx, .js, .py, .go, etc.`
+          )
+        }
+        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
       })

src/tools/lsp/directory-diagnostics.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from "bun:test"
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from "fs"
+import { join } from "path"
+import os from "os"
+
+import { isDirectoryPath } from "./lsp-client-wrapper"
+import { aggregateDiagnosticsForDirectory } from "./directory-diagnostics"
+
+describe("directory diagnostics", () => {
+  describe("isDirectoryPath", () => {
+    it("returns true for existing directory", () => {
+      const tmp = mkdtempSync(join(os.tmpdir(), "omo-isdir-"))
+      try {
+        expect(isDirectoryPath(tmp)).toBe(true)
+      } finally {
+        rmSync(tmp, { recursive: true, force: true })
+      }
+    })
+
+    it("returns false for existing file", () => {
+      const tmp = mkdtempSync(join(os.tmpdir(), "omo-isdir-file-"))
+      try {
+        const file = join(tmp, "test.txt")
+        writeFileSync(file, "content")
+        expect(isDirectoryPath(file)).toBe(false)
+      } finally {
+        rmSync(tmp, { recursive: true, force: true })
+      }
+    })
+
+    it("returns false for non-existent path", () => {
+      const nonExistent = join(os.tmpdir(), "omo-nonexistent-" + Date.now())
+      expect(isDirectoryPath(nonExistent)).toBe(false)
+    })
+  })
+
+  describe("aggregateDiagnosticsForDirectory", () => {
+    it("throws error when extension does not start with dot", async () => {
+      const tmp = mkdtempSync(join(os.tmpdir(), "omo-aggr-ext-"))
+      try {
+        await expect(aggregateDiagnosticsForDirectory(tmp, "ts")).rejects.toThrow(
+          'Extension must start with a dot (e.g., ".ts", not "ts")'
+        )
+      } finally {
+        rmSync(tmp, { recursive: true, force: true })
+      }
+    })
+
+    it("throws error when directory does not exist", async () => {
+      const nonExistent = join(os.tmpdir(), "omo-nonexistent-dir-" + Date.now())
+      await expect(aggregateDiagnosticsForDirectory(nonExistent, ".ts")).rejects.toThrow(
+        "Directory does not exist"
+      )
+    })
+  })
+})

src/tools/lsp/directory-diagnostics.ts

@@ -0,0 +1,144 @@
+import { existsSync, lstatSync, readdirSync, type Stats } from "fs"
+import { extname, join, resolve } from "path"
+
+import { findServerForExtension } from "./config"
+import { findWorkspaceRoot, formatServerLookupError } from "./lsp-client-wrapper"
+import { filterDiagnosticsBySeverity, formatDiagnostic } from "./lsp-formatters"
+import { LSPClient } from "./lsp-client"
+import { lspManager } from "./lsp-server"
+import { DEFAULT_MAX_DIAGNOSTICS, DEFAULT_MAX_DIRECTORY_FILES } from "./constants"
+import type { Diagnostic } from "./types"
+
+const SKIP_DIRECTORIES = new Set(["node_modules", ".git", "dist", "build", ".next", "out"])
+
+function collectFilesWithExtension(dir: string, extension: string, maxFiles: number): string[] {
+  const files: string[] = []
+
+  function walk(currentDir: string): void {
+    if (files.length >= maxFiles) return
+
+    let entries: string[] = []
+    try {
+      entries = readdirSync(currentDir)
+    } catch {
+      return
+    }
+
+    for (const entry of entries) {
+      if (files.length >= maxFiles) return
+
+      const fullPath = join(currentDir, entry)
+
+      let stat: Stats | undefined
+      try {
+        stat = lstatSync(fullPath)
+      } catch {
+        continue
+      }
+
+      if (!stat || stat.isSymbolicLink()) {
+        continue
+      }
+
+      if (stat.isDirectory()) {
+        if (!SKIP_DIRECTORIES.has(entry)) {
+          walk(fullPath)
+        }
+      } else if (stat.isFile()) {
+        if (extname(fullPath) === extension) {
+          files.push(fullPath)
+        }
+      }
+    }
+  }
+
+  walk(dir)
+  return files
+}
+
+export async function aggregateDiagnosticsForDirectory(
+  directory: string,
+  extension: string,
+  severity?: "error" | "warning" | "information" | "hint" | "all",
+  maxFiles: number = DEFAULT_MAX_DIRECTORY_FILES
+): Promise<string> {
+  if (!extension.startsWith(".")) {
+    throw new Error(
+      `Extension must start with a dot (e.g., ".ts", not "${extension}"). ` +
+        `Use ".${extension}" instead.`
+    )
+  }
+
+  const absDir = resolve(directory)
+  if (!existsSync(absDir)) {
+    throw new Error(`Directory does not exist: ${absDir}`)
+  }
+
+  const serverResult = findServerForExtension(extension)
+  if (serverResult.status !== "found") {
+    throw new Error(formatServerLookupError(serverResult))
+  }
+
+  const server = serverResult.server
+  const allFiles = collectFilesWithExtension(absDir, extension, maxFiles + 1)
+  const wasCapped = allFiles.length > maxFiles
+  const filesToProcess = allFiles.slice(0, maxFiles)
+
+  const root = findWorkspaceRoot(absDir)
+
+  const allDiagnostics: Diagnostic[] = []
+  const fileErrors: { file: string; error: string }[] = []
+
+  let client: LSPClient
+  try {
+    client = await lspManager.getClient(root, server)
+
+    for (const file of filesToProcess) {
+      try {
+        const result = await client.diagnostics(file)
+        const filtered = filterDiagnosticsBySeverity(result.items, severity)
+        allDiagnostics.push(...filtered)
+      } catch (e) {
+        fileErrors.push({
+          file,
+          error: e instanceof Error ? e.message : String(e),
+        })
+      }
+    }
+  } finally {
+    lspManager.releaseClient(root, server.id)
+  }
+
+  const displayDiagnostics = allDiagnostics.slice(0, DEFAULT_MAX_DIAGNOSTICS)
+  const wasDiagCapped = allDiagnostics.length > DEFAULT_MAX_DIAGNOSTICS
+
+  const lines: string[] = [
+    `Directory: ${absDir}`,
+    `Extension: ${extension}`,
+    `Files scanned: ${filesToProcess.length}${wasCapped ? ` (capped at ${maxFiles})` : ""}`,
+    `Files with errors: ${fileErrors.length}`,
+    `Total diagnostics: ${allDiagnostics.length}`,
+  ]
+
+  if (fileErrors.length > 0) {
+    lines.push("", "File processing errors:")
+    for (const { file, error } of fileErrors) {
+      lines.push(`  ${file}: ${error}`)
+    }
+  }
+
+  if (displayDiagnostics.length > 0) {
+    lines.push("")
+    for (const diag of displayDiagnostics) {
+      lines.push(formatDiagnostic(diag))
+    }
+    if (wasDiagCapped) {
+      lines.push(
+        "",
+        `... (${allDiagnostics.length - DEFAULT_MAX_DIAGNOSTICS} more diagnostics not shown)`
+      )
+    }
+  }
+
+  return lines.join("\n")
+}

src/tools/lsp/lsp-client-wrapper.ts

@@ -1,6 +1,6 @@
 import { extname, resolve } from "path"
 import { fileURLToPath } from "node:url"
-import { existsSync } from "fs"
+import { existsSync, statSync } from "fs"
 
 import { LSPClient, lspManager } from "./client"
 import { findServerForExtension } from "./config"
@@ -33,6 +33,13 @@ export function uriToPath(uri: string): string {
   return fileURLToPath(uri)
 }
 
+export function isDirectoryPath(filePath: string): boolean {
+  if (!existsSync(filePath)) {
+    return false
+  }
+  return statSync(filePath).isDirectory()
+}
+
 export function formatServerLookupError(result: Exclude<ServerLookupResult, { status: "found" }>): string {
   if (result.status === "not_installed") {
     const { server, installHint } = result
@@ -70,6 +77,14 @@ export function formatServerLookupError(result: Exclude<ServerLookupResult, { st
 
 export async function withLspClient<T>(filePath: string, fn: (client: LSPClient) => Promise<T>): Promise<T> {
   const absPath = resolve(filePath)
+
+  if (isDirectoryPath(absPath)) {
+    throw new Error(
+      `Directory paths are not supported by this LSP tool. ` +
+        `Use lsp_diagnostics with the 'extension' parameter for directory diagnostics.`
+    )
+  }
+
   const ext = extname(absPath)
   const result = findServerForExtension(ext)