Post-Edit Formatter

Run your project’s formatter after every agent file edit so style stays consistent without extra steps.

from praisonaiagents import Agent
from praisonaiagents.tools.edit_tools import create_edit_tools

edit_tools = create_edit_tools(post_edit_format="auto")

coder = Agent(
    name="Coder",
    instructions="Edit files cleanly and keep formatting consistent.",
    tools=edit_tools,
)
coder.start("Refactor utils.py to use list comprehensions")

The user asks for a refactor; the formatter runs automatically after each file edit.

How It Works

Quick Start

Simple Usage

Enable auto-formatting on edit tools:

from praisonaiagents import Agent
from praisonaiagents.tools.edit_tools import create_edit_tools

edit_tools = create_edit_tools(post_edit_format="auto")

coder = Agent(
    name="Coder",
    instructions="Edit the file as requested.",
    tools=edit_tools,
)
coder.start("Add type hints to models.py")

With Configuration

Pin formatters per extension:

from praisonaiagents import Agent
from praisonaiagents.tools.edit_tools import create_edit_tools

edit_tools = create_edit_tools(
    post_edit_format="auto",
    formatters={
        ".py": ["ruff", "format", "{path}"],
        ".ts": ["./node_modules/.bin/prettier", "--write", "{path}"],
    },
)

coder = Agent(name="PolyglotCoder", instructions="Edit Python and TypeScript.", tools=edit_tools)

A missing or failing formatter never fails the edit — the original write is kept and errors are logged at debug level.

How It Works

After a successful edit_file or apply_patch, the pipeline detects a formatter by file extension, runs it, and re-reads the file on exit code 0.

Extension	Default command
`.py`	`ruff format {path}` (falls back to `black`)
`.js`, `.ts`, `.tsx`, `.json`, `.css`, `.md`	`prettier --no-config --no-editorconfig --write {path}`
`.go`	`gofmt -w {path}`
`.rs`	`rustfmt {path}`

The {path} placeholder is the absolute path to the edited file. If omitted from your argv list, it is appended automatically.

Diagnostics: unavailable note

When an edited file has a known LSP language whose server is not installed and no legacy checker is available, the edit output now appends a one-time-per-language note:

Diagnostics (lsp:<lang>): unavailable — language server `<cmd>` not found on PATH; install with `<hint>`

For example, editing a Python file with no pylsp on PATH:

Diagnostics (lsp:python): unavailable — language server `pylsp` not found on PATH; install with `pip install python-lsp-server`

This replaces the previous silent no-op — the lost self-correction signal is now visible. The note is deduplicated per language per run, so install the server once and it disappears. See LSP Auto-Detect to probe availability before you run.

Configuration Options

Option	Type	Default	Description
`post_edit_format`	`str`	`"off"`	`"off"`, `"auto"`, or `"on"`
`formatters`	`dict[str, list[str]]`	Built-in map	Per-extension formatter argv
`post_edit_diagnostics`	`str`	`"auto"`	Separate linter/diagnostics pass

Best Practices

Start with auto mode

post_edit_format="auto" runs a formatter only when one is on PATH — zero cost when none is installed.

Use project-local prettier

Prefer ./node_modules/.bin/prettier so the version matches package.json.

Pin formatter versions in CI

Match local and CI formatter versions to avoid diff churn between runs.

Skip when CI already formats

Most useful for interactive agent sessions where you want immediate clean output.

File Editing

Core edit and patch tools

Code Agent

Code assistant configuration

LSP Auto-Detect

Probe server availability before you edit

Getting Started

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Getting Started (No Code)

Post-Edit Formatter

How It Works

Quick Start

How It Works

Diagnostics: unavailable note

Configuration Options

Best Practices

File Editing

Code Agent

LSP Auto-Detect

​How It Works

​Quick Start

​How It Works

​Diagnostics: unavailable note

​Configuration Options

​Best Practices

​Related

File Editing

Code Agent

LSP Auto-Detect

How It Works

Quick Start

How It Works

Diagnostics: unavailable note

Configuration Options

Best Practices

Related