name: searching-codebases description: >- Find code by regex pattern or natural language concept in any codebase. Auto-routes between n-gram indexed regex search (2-20x faster than ripgrep) and TF-IDF semantic search. Expands results to full functions via tree-sitting AST data. Accepts GitHub URLs, local directories, uploaded files/archives, or project knowledge. Use when asked to find implementations, search for patterns, or answer "where is X" / "how does Y work" about code. Triggers on "search this repo", "find where X is", "grep for", "what handles Y", regex patterns, or natural-language questions about code. This is the convergent "find X" skill — for first-encounter orientation, use exploring-codebases instead. metadata: version: 2.0.0

Searching Codebases

Find code in any codebase by pattern or concept. One entry point, two search strategies, automatic routing.

Prerequisites

uv tool install ripgrep

tree-sitting (for structural context expansion) installs automatically when the --expand flag is used.

Primary Command

SKILL_DIR=/mnt/skills/user/searching-codebases

python3 $SKILL_DIR/scripts/search.py SOURCE "query1" ["query2" ...] [OPTIONS]

SOURCE is any of:

• Local directory path
• GitHub URL (downloads tarball automatically)
• uploads (uses /mnt/user-data/uploads/)
• project (uses /mnt/project/)
• Path to a .zip or .tar.gz archive

Search Modes

Regex mode (patterns, identifiers, literal text):

python3 $SKILL_DIR/scripts/search.py ./repo "def handle_error"
python3 $SKILL_DIR/scripts/search.py ./repo "class.*Exception" --regex
python3 $SKILL_DIR/scripts/search.py ./repo "TODO|FIXME|HACK"

Semantic mode (concepts, natural language):

python3 $SKILL_DIR/scripts/search.py ./repo "retry logic with backoff" --semantic
python3 $SKILL_DIR/scripts/search.py ./repo "authentication flow"
python3 $SKILL_DIR/scripts/search.py ./repo "error handling strategy"

Auto-detection: short queries and code-like tokens → regex. Multi-word natural language → semantic. Override with --regex or --semantic.

Options

• --regex / --semantic: Force search mode
• --expand: Return full function bodies via tree-sitting AST context
• --benchmark: Compare indexed regex vs brute-force ripgrep
• --branch NAME: Git branch for GitHub URLs (default: main)
• --skip DIRS: Comma-separated directories to skip
• --json: Machine-readable output
• -v: Show index stats and query routing decisions

How It Works

Regex search builds a sparse n-gram inverted index over all files. Queries are decomposed into literal fragments, looked up in the index to identify candidate files (typically 90-99% reduction), then verified with ripgrep. Frequency-weighted n-grams make rare character sequences more selective.

Semantic search builds a TF-IDF index over code chunks (functions, classes, structural entries). Queries are ranked by cosine similarity.

Context expansion (--expand) uses tree-sitting's AST cache to identify function/class boundaries, returning complete structural units rather than line fragments. On first use, tree-sitting scans the repo (~700ms for 250 files); subsequent expansions are sub-millisecond.

Small codebases (< 20 files) skip indexing entirely — direct ripgrep is faster when there's nothing to narrow.

Mixed Queries

Multiple queries can use different modes in a single invocation. Each query is auto-routed independently, and indexes are built once per mode:

python3 $SKILL_DIR/scripts/search.py ./repo \
  "class.*Error" \
  "error recovery strategy" \
  "def retry"

Dependencies

• tree-sitting: Provides AST-based context expansion for --expand. Not required — search works without it, just with less structural context in results.
• ripgrep: Required for regex verification. Install via uv tool install ripgrep.
• scikit-learn: Required for semantic mode. Installs automatically.

When to Use

• Known target: "where is the retry logic?", "find all error handlers"
• Pattern matching: regex across large codebases with indexed speedup
• Concept search: "authentication flow", "database connection pooling"
• Cross-reference: find all callers/users of a specific function

When NOT to Use

• First encounter: "what does this repo do?" → use exploring-codebases
• Repos under ~10 files: just read them directly
• Exact symbol lookup: find_symbol('ClassName') via tree-sitting is simpler
• Structural overview: use tree-sitting's tree_overview() / dir_overview()

Files

• scripts/search.py — Entry point, query routing, output formatting
• scripts/resolve.py — Input source resolution (GitHub, uploads, archives)
• scripts/context.py — tree-sitting-based AST context expansion
• scripts/ngram_index.py — Sparse n-gram inverted index, regex decomposition
• scripts/sparse_ngrams.py — Core n-gram algorithms, frequency weights
• scripts/code_rag.py — TF-IDF semantic search over code chunks