refactor(ast-grep): inline tool descriptions and simplify pattern hints

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/tools/ast-grep/tools.ts

@@ -3,12 +3,6 @@ import { tool, type ToolDefinition } from "@opencode-ai/plugin/tool"
 import { CLI_LANGUAGES } from "./constants"
 import { runSg } from "./cli"
 import { formatSearchResult, formatReplaceResult } from "./result-formatter"
-import { getPatternHint } from "./pattern-hints"
-import {
-  AST_GREP_REPLACE_DESCRIPTION,
-  AST_GREP_SEARCH_DESCRIPTION,
-  AST_GREP_SEARCH_PATTERN_PARAM,
-} from "./tool-descriptions"
 import type { CliLanguage } from "./types"
 
 async function showOutputToUser(context: unknown, output: string): Promise<void> {
@@ -18,11 +12,39 @@ async function showOutputToUser(context: unknown, output: string): Promise<void>
   await ctx.metadata?.({ metadata: { output } })
 }
 
+function getEmptyResultHint(pattern: string, lang: CliLanguage): string | null {
+  const src = pattern.trim()
+
+  if (lang === "python") {
+    if (src.startsWith("class ") && src.endsWith(":")) {
+      const withoutColon = src.slice(0, -1)
+      return `Hint: Remove trailing colon. Try: "${withoutColon}"`
+    }
+    if ((src.startsWith("def ") || src.startsWith("async def ")) && src.endsWith(":")) {
+      const withoutColon = src.slice(0, -1)
+      return `Hint: Remove trailing colon. Try: "${withoutColon}"`
+    }
+  }
+
+  if (["javascript", "typescript", "tsx"].includes(lang)) {
+    if (/^(export\s+)?(async\s+)?function\s+\$[A-Z_]+\s*$/i.test(src)) {
+      return `Hint: Function patterns need params and body. Try "function $NAME($$$) { $$$ }"`
+    }
+  }
+
+  return null
+}
+
 export function createAstGrepTools(ctx: PluginInput): Record<string, ToolDefinition> {
   const ast_grep_search: ToolDefinition = tool({
-    description: AST_GREP_SEARCH_DESCRIPTION,
+    description:
+      "Search code patterns across filesystem using AST-aware matching. Supports 25 languages. " +
+      "Use meta-variables: $VAR (single node), $$$ (multiple nodes). " +
+      "IMPORTANT: Patterns must be complete AST nodes (valid code). " +
+      "For functions, include params and body: 'export async function $NAME($$$) { $$$ }' not 'export async function $NAME'. " +
+      "Examples: 'console.log($MSG)', 'def $FUNC($$$):', 'async function $NAME($$$)'",
     args: {
-      pattern: tool.schema.string().describe(AST_GREP_SEARCH_PATTERN_PARAM),
+      pattern: tool.schema.string().describe("AST pattern with meta-variables ($VAR, $$$). Must be complete AST node."),
       lang: tool.schema.enum(CLI_LANGUAGES).describe("Target language"),
       paths: tool.schema.array(tool.schema.string()).optional().describe("Paths to search (default: ['.'])"),
       globs: tool.schema.array(tool.schema.string()).optional().describe("Include/exclude globs (prefix ! to exclude)"),
@@ -41,7 +63,7 @@ export function createAstGrepTools(ctx: PluginInput): Record<string, ToolDefinit
         let output = formatSearchResult(result)
 
         if (result.matches.length === 0 && !result.error) {
-          const hint = getPatternHint(args.pattern, args.lang as CliLanguage)
+          const hint = getEmptyResultHint(args.pattern, args.lang as CliLanguage)
           if (hint) {
             output += `\n\n${hint}`
           }
@@ -58,7 +80,10 @@ export function createAstGrepTools(ctx: PluginInput): Record<string, ToolDefinit
   })
 
   const ast_grep_replace: ToolDefinition = tool({
-    description: AST_GREP_REPLACE_DESCRIPTION,
+    description:
+      "Replace code patterns across filesystem with AST-aware rewriting. " +
+      "Dry-run by default. Use meta-variables in rewrite to preserve matched content. " +
+      "Example: pattern='console.log($MSG)' rewrite='logger.info($MSG)'",
     args: {
       pattern: tool.schema.string().describe("AST pattern to match"),
       rewrite: tool.schema.string().describe("Replacement pattern (can use $VAR from pattern)"),