Patchloom

Patchloom is a Rust CLI for structured file edits, built for AI coding agents.

AI agents are good at reasoning about code but bad at editing config files. When an agent needs to bump a version in config.yaml, it reaches for sed or text replacement. That works until the regex strips a YAML comment, breaks indentation, or produces invalid syntax. When the task touches six files, that means six separate tool calls, each a full round-trip back to the LLM. And on Windows, sed and jq do not exist.

Patchloom fixes all three problems with a single Rust binary.

What it does

Structured editing: Edit JSON, YAML, and TOML files by selector path, not regex. Comments and formatting are preserved because the file is parsed, not pattern-matched.
Batch operations: Bundle multiple file edits into a single tool call, cutting round-trips from six to one.
Cross-platform: Works identically on Linux, macOS, and Windows with zero dependencies.
Safe by default: All write operations preview changes without mutating files unless --apply is passed.
MCP server: Exposes all operations as structured tool calls for MCP-capable agents.

Quick example

# Edit a YAML value by selector; comments and formatting survive
patchloom doc set config.yaml database.port 5432 --apply

# Version bump across 6 files in a single tool call
patchloom batch --apply <<'EOF'
doc.set package.json version "2.0.0"
doc.set config.yaml app.version "2.0.0"
replace README.md "1.0.0" "2.0.0"
EOF

20 commands

Category	Command	Description
Text	`search`	Literal or regex search across files
	`replace`	Mechanical string replacement with diff preview
	`patch`	Preview or apply unified diffs
Structured	`doc`	Parser-backed JSON, YAML, and TOML operations
	`md`	Markdown section-aware operations
Files	`create`	Create a new file with content
	`delete`	Delete a file
	`rename`	Rename or move a file
	`read`	Read file contents with optional line range
	`status`	Show uncommitted file changes
Batch	`tx`	Execute a multi-operation plan atomically
	`batch`	Line-oriented batch operations
Normalize	`tidy`	Whitespace, line ending, and final newline normalization
Safety	`undo`	Restore files from backup
Agent	`mcp-server`	MCP protocol server for structured tool calls
	`agent-rules`	Print agent rules for AGENTS.md
	`schema`	Export operation schemas with tier filtering
	`explain`	Explain a tx plan in plain English
Setup	`init`	Set up patchloom in the current project
	`completions`	Generate shell completions

As a Rust library

Patchloom is also a Rust library. Add it as a dependency to embed structured file editing in your own tools:

[dependencies]
patchloom = { version = "0.1", default-features = false }

The api module exposes doc, replace, markdown, file, and patch operations. All API types are Send + Sync. Disabling default features omits the MCP server and its async dependencies.

See the crate documentation for the full API surface.

Get started

Head to Installation to install, then follow the Quickstart to make your first edit.