Every edition runs the same loop — analyze, act, attest — at a different depth. Pick by how much of the codebase your agent touches.
ast-grep and comby are free, and built for humans. So is act101 Builder Edition — free forever, and built for your agent. Engineering at $29 is the commercial tier: the full mutation toolkit, refactor verification with receipts, and a commercial license. See the head-to-heads: vs ast-grep · vs comby · vs semgrep.
Save ~15% with annual billing.
Builder already beats ast-grep and comby head-to-head, free. $29 adds the commercial license and the verify-and-receipt loop your agent can branch on.
7-day free trial, all features.
Secure checkout by Paddle
7-day free trial, all features.
Secure checkout by Paddle
7-day free trial, all features.
Secure checkout by Paddle
All prices USD. 7-day free trial, all features.
| Capability | Builder | Engineering | Architecture | Elite | Enterprise |
|---|---|---|---|---|---|
| Read any codebase by structure — outlines, references, callers, call graphs | ✓ | ✓ | ✓ | ✓ | ✓ |
| Rename + fix-auto | ✓ | ✓ | ✓ | ✓ | ✓ |
| See what code does before changing it — side effects, data flow, unsafe constructs | ✓ | ✓ | ✓ | ✓ | ✓ |
| Change code, not just read it — extract, inline, wrap, introduce, generate | — | ✓ | ✓ | ✓ | ✓ |
| Prove a refactor preserved behavior, and catch leaked secrets | — | ✓ | ✓ | ✓ | ✓ |
| Restructure whole modules, and trace untrusted data from where it enters to where it lands | — | — | ✓ | ✓ | ✓ |
| Rank work by real evidence — what changes most, what tests cover, who owns it | — | — | ✓ | ✓ | ✓ |
| 25 premium grammars (COBOL, Fortran, Solidity, HDL…) | — | — | — | ✓ | ✓ |
| Port codebases across languages, and prove the result behaves like the original | — | — | — | — | ✓ |
Full per-tool detail in the feature matrix.
ast-grep, comby, and semgrep are pattern-matching and structural search tools designed for humans. act is one native binary that exposes typed, parameterised refactor operations through MCP and a CLI, with automatic checkpointing, instant undo, and a merge gate that returns a verdict and a receipt. Full comparisons: act101 vs ast-grep · act101 vs comby · act101 vs semgrep.
It's measured, not estimated: ~88% fewer tokens on query operations — skeleton, references, callers — versus reading whole files, from timed runs against real repositories. The method and the raw numbers are published. It applies to reads, not writes, and it's a side effect of answering from the AST instead of shipping whole files.
Porting is a workflow, not a button. The 10 porting operations plus parity
verification make each step checkable — the manifest keeps score, and
verify_port_parity checks that a ported function behaves like the original.
Small, well-tested modules port well today; a large legacy migration is a program of
work run step by step under the manifest — that's what the Enterprise engagement covers.
Evaluate the claim the cheap way: port one module and read the parity report.
Yes. act ships as one native binary with two interfaces — MCP and a CLI — both exposing the same 182 AST-aware refactor operations. Agents like Claude Code, Cursor, Codex, and OpenCode call rename, extract function, inline, move symbol, and 60+ Python-specific refactors directly, with cross-file import updates, automatic checkpoints, and instant undo.
Yes. act provides 10 porting operations that let an agent define a source-to-target contract, inventory every symbol that must move, resolve dependency ordering, and track the migration step by step. The same workflow handles Ruby to Elixir, COBOL to Java, Python 2 to Python 3, and arbitrary pairs across 163 grammars.
act is one native binary that is both an MCP server and a CLI. Run
act mcp serve and Claude Code, Cursor, OpenAI Codex, and OpenCode connect
via stdio or HTTP+SSE — or run any act subcommand directly. Marketplace install blocks
for each agent are on the install section.
One native binary, every grammar, zero setup. Builder Edition is free.
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