ast-grep vs Code Fundi

ast-grep is a free, open-source tool for structural code search, linting, and rewriting. It matches patterns against syntax-tree nodes, helping developers locate and change code across a codebase rather than searching plain text. Its CLI can preview and apply rewrites interactively, and scan configurable YAML rules with error, warning, info, or hint severity. Rules can combine pattern, kind, regex, relational, and composite conditions, and CLI commands help create and snapshot-test them. The project says it supports more than 20 languages and can load custom languages. JavaScript and WebAssembly APIs allow programmatic syntax-tree work; a browser playground offers a way to try patterns without local installation. Editor options include a VS Code extension and language-server setups, including for Vim and Neovim. The tool is free, has a web interface, and is distributed through package managers or built from source. Its FAQ notes that some advanced static-analysis information is unsupported, and one rule cannot target multiple languages at once.

Code Fundi turns indexed repositories into searchable maps of a codebase for AI agents, teams, and applications. Search combines semantic search with documentation-aware and code grep; research adds AI synthesis grounded in repository search results. Its blast-radius analysis maps dependents, data flows, entry points, and call edges, and requires a DEV plan or higher. Users can access it through a web app, MCP server, HTTP API, or extensions for VS Code and Cursor; the maker also lists Windsurf support. The versioned API covers search, research, indexing, blast-radius analysis, Markdown blueprints, file documentation, history, and account utilities. Private repositories require a linked GitHub account with access. The maker says proprietary code is not used to train public models and describes its approach as zero-data retention. Plans set credit allowances, private repository caps, usage-log retention, and Markdown detail levels; research and chat can add model usage on top of base credit costs. Free includes 500 credits and email support; paid plans are Dev at $21 a month, Startup at $62 a month, and Pro at $210 a month.