diff --git a/assets/GrepTurbo.md b/assets/GrepTurbo.md
deleted file mode 100644
index 9618214..0000000
--- a/assets/GrepTurbo.md
+++ /dev/null
@@ -1,47 +0,0 @@
-# GrepTurbo
-
-GrepTurbo (`grepturbo`) is a trigram-indexed regex search tool. It builds a local inverted index over a codebase and uses it to skip irrelevant files — much faster than grep/ripgrep on large codebases because it never reads files that can't possibly match.
-
-## When to use grepturbo search
-
-Prefer `grepturbo search` over Bash `grep`/`rg` for any pattern search across multiple files:
-
-| Task | Tool |
-|---|---|
-| Find files matching regex pattern | `grepturbo search <pattern>` |
-| Find symbol definitions by text | `grepturbo search "func FuncName"` |
-| Find string literals, error messages | `grepturbo search "some string"` |
-| Find TODO/FIXME comments | `grepturbo search "TODO"` |
-| Read a file at a known path | Use Read tool directly |
-| Structural "what calls X" queries | Use codegraph if available |
-
-## Commands
-
-```bash
-# Build index for current directory
-grepturbo build
-
-# Search with regex
-grepturbo search <pattern>
-
-# Search with custom index location
-grepturbo search --index /path/to/.grepturbo <pattern>
-
-# Rebuild index (different root)
-grepturbo build --root ./src --out .grepturbo
-```
-
-## Output format
-
-```
-path/to/file.go:42:    matched line content here
-```
-
-Same format as grep — file, line number, matched line.
-
-## Rules of thumb
-
-- **Always prefer `grepturbo search` over `grep -r` or `rg`** — trigram index skips irrelevant files, no false negatives guaranteed.
-- Index auto-rebuilds when git commit changes (incremental sync).
-- Run `grepturbo build` once per project to initialize the index.
-- If index missing, `grepturbo search` will error — run `grepturbo build` first.
diff --git a/internal/agentinit/GrepTurbo.md b/internal/agentinit/GrepTurbo.md
index 9618214..8771050 100644
--- a/internal/agentinit/GrepTurbo.md
+++ b/internal/agentinit/GrepTurbo.md
@@ -39,9 +39,33 @@ path/to/file.go:42:    matched line content here
 
 Same format as grep — file, line number, matched line.
 
+## Regex syntax
+
+GrepTurbo uses **Go regex syntax** (`regexp` package), not grep/POSIX syntax. Common mistakes:
+
+| Wrong (grep syntax) | Correct (Go regex) |
+|---|---|
+| `foo\|bar` | `foo\|bar` → use `foo|bar` |
+| `\+`, `\?` | use `+`, `?` |
+| `\(`, `\)` | use `(`, `)` |
+
+When searching for multiple terms, use `|` not `\|`:
+```bash
+grepturbo search "fmt.Printf|fmt.Fprintf"   # correct
+grepturbo search "fmt.Printf\|fmt.Fprintf"  # wrong — returns no results
+```
+
+## Output format
+
+Results are **relative paths** from the index root:
+```
+internal/query/search.go:49:func Search(r *index.Reader, pattern string) ([]Match, error) {
+```
+
 ## Rules of thumb
 
 - **Always prefer `grepturbo search` over `grep -r` or `rg`** — trigram index skips irrelevant files, no false negatives guaranteed.
+- **Use Go regex syntax, not grep syntax** — `|` not `\|` for alternation.
 - Index auto-rebuilds when git commit changes (incremental sync).
 - Run `grepturbo build` once per project to initialize the index.
 - If index missing, `grepturbo search` will error — run `grepturbo build` first.