ai: add ast-grep (#13539)

Author: Boshen

.github/workflows/copilot-setup-steps.yml

@@ -32,7 +32,7 @@ jobs:
         with:
           cache-key: warm
           save-cache: false
-          tools: just,watchexec-cli,cargo-insta,typos-cli,cargo-shear,dprint
+          tools: just,cargo-insta,typos-cli,cargo-shear,dprint,ast-grep
           components: clippy rust-docs rustfmt
 
       - uses: oxc-project/setup-node@f42e3bda950c7454575e78ee4eaac880a077700c # v1.0.0

AGENTS.md

@@ -39,9 +39,10 @@ Prerequisites: Rust (MSRV: 1.87.0), Node.js, pnpm, just
 
 **Setup Notes:**
 
-- All tools already installed (`cargo-insta`, `typos-cli`, `cargo-shear`, `dprint`)
+- All tools already installed (`cargo-insta`, `typos-cli`, `cargo-shear`, `dprint`, `ast-grep`)
 - Rust components already installed (`clippy`, `rust-docs`, `rustfmt`)
 - Run `just ready` after commits for final checks
+- You run in an environment where `ast-grep` is available; whenever a search requires syntax-aware or structural matching, default to `ast-grep --lang rust -p '<pattern>'` (or set `--lang` appropriately) and avoid falling back to text-only tools like `rg` or `grep` unless I explicitly request a plain-text search.
 
 ### Essential Commands
 

CLAUDE.md

@@ -10,3 +10,7 @@ Oxc (The Oxidation Compiler) is a high-performance JavaScript/TypeScript toolcha
 
 - Agent-specific guide: See [AGENTS.md](AGENTS.md)
 - Architecture details: See [ARCHITECTURE.md](ARCHITECTURE.md)
+
+## Development
+
+You run in an environment where `ast-grep` is available; whenever a search requires syntax-aware or structural matching, default to `ast-grep --lang rust -p '<pattern>'` (or set `--lang` appropriately) and avoid falling back to text-only tools like `rg` or `grep` unless I explicitly request a plain-text search.