editomatic

Whitespace-tolerant edit fallback for Pi — for local/quantized LLM users who also use gentle-pi.

Upgrade to 1.1.0+ (diagnostics + dry-run)

Versions before 1.0.5 could silently corrupt indent-sensitive files (especially Python) when aggressive fallback matching flattened indentation and rewrote the wrong region.

1.0.5+ fail-closed matching · 1.0.6+ backups + atomic write · 1.0.7 multi-edit hardening · 1.0.8 Myers line diffs · 1.1.0 match-failure diagnostics, dry-run preview, correct indent-unit detection, remapped Python syntax errors.

Full details: CHANGELOG.md · lockdown: EDITOMATIC_STRICT=1

editomatic is not a replacement for Pi's built-in edit tool. It is a fallback for models that struggle with exact text matching due to indentation drift, trailing whitespace, or Unicode normalization differences — common failure modes of local and quantized language models.

The problem

Pi's built-in edit tool uses exact string matching. When a model's output contains different indentation levels, trailing spaces, or Unicode smart quotes, the edit fails. Quantized models (4-bit, 8-bit) are especially prone to these drift patterns.

# What the model sends:
{ "oldText": "function hello() {}" }

# What the file actually has:
"    function hello() {\n      // does nothing\n    }"

# Result: edit fails, model has to guess again

editomatic handles this with progressive fallback matching and fail-closed safety so it never silently destroys structure.

How it works

Matching strategies (first success wins):

Pure “strip all leading whitespace and hope” is not used. Two blocks that only look identical after flattening structure are rejected or treated as ambiguous.

Replacement preserves:

• Original BOM and line endings (CRLF vs LF)
• Unchanged lines outside the match
• Tab/space convention and relative indent structure
• Trailing newlines when intentional in newText

Write safety

Every successful write:

1. Saves previous content to yourfile.ext.editomatic-bak
2. Writes new content to a temp file, then renames (atomic on the same filesystem)
3. For Python paths, runs best-effort python -m py_compile before overwrite when an interpreter is available (errors cite the real path and proposed-file line numbers, not a temp path)

Dry-run preview

{ "path": "app.py", "dryRun": true, "edits": [{ "oldText": "...", "newText": "..." }] }

Matches and builds the same Myers diff (and Python syntax gate) but does not write or create a backup. Use when verifying a large newText before committing the change.

Match-failure diagnostics

When oldText is not found, the error includes the closest candidate region, the first differing line (expected vs actual), and whether the drift is whitespace-only. That saves a full re-read when a successive edit used stale text.

Emergency lockdown

export EDITOMATIC_STRICT=1   # exact + fuzzy only

Install

pi install npm:edit-o-matic

Project-local:

pi install npm:edit-o-matic -l

Confirm 1.1.0 or later. See CHANGELOG.md.

Recovery from backup

cp path/to/file.py.editomatic-bak path/to/file.py

Usage

The tool registers as editomatic in Pi's tool registry.

Parameters

{
  path: string;          // Path to file (relative or absolute)
  edits: Array<{
    oldText: string;     // Text to find (whitespace-tolerant)
    newText: string;     // Replacement text ("" = delete)
  }>;
  dryRun?: boolean;      // Preview diff + syntax check; no write
}

Tips

• Keep oldText small and unique — ambiguous matches are rejected; not-found errors include first-diff diagnostics
• One call, multiple edits — searched against original content; applied bottom-up safely
• After a successful edit, re-read or use updated text for further edits to the same region
• Preserve relative indentation in multi-line blocks (critical for Python)
• dryRun: true — verify large replacements before writing
• Deletion — empty newText deletes matched lines; "\n" inserts a blank line

When to use editomatic vs built-in edit

Indentation context injection

On before_agent_start, editomatic injects per-file indent style, short indent examples, and a Python-specific reminder that indentation is syntax. That reduces how often fallback matching is needed.

Package contents

Changelog

See CHANGELOG.md.

Building

npm install
npm run build
npm run check
npm test

License

MIT — LICENSE