Compute structured line-by-line text diffs with optional unified output via @mukundakatta/diff-mcp

@mukundakatta/diff-mcp v0.1.0 — Structured Line Diff

Install: npm install @mukundakatta/diff-mcp Server: node node_modules/@mukundakatta/diff-mcp/dist/server.js (stdio) Tools: 1 tool: diff

Tool: diff

• Params: {a: string, b: string, unified?: boolean} — original text, new text, optionally render unified-diff output
• Returns: {entries: [{op, text}], unified?: string} — structured array of operations (eq, del, add) per line, plus optional unified-diff render

Key observations from 10 verified calls:

1. Three operations: eq (unchanged), del (removed from a), add (added in b). Clean, parseable structure.
2. Unified output: when unified: true, includes a string with prefix for context, - for deletions, + for additions. When texts are identical, no unified field.
3. Line-level granularity: diffs split on newlines. Whitespace changes within a line produce a del+add pair for that line (not character-level highlighting).
4. Code diffs work well: multi-line function edits produce clean del/add blocks with shared context (} closing brace detected as eq).
5. Empty string handling: empty→content produces {op:"del",text:""} + adds; content→empty produces dels + {op:"add",text:""}.
6. Unicode-safe: Turkish characters (ç, ü, ö) and other UTF-8 handled correctly.
7. Identical texts: returns all eq entries, no unified field, no spurious diff markers.
8. p50 latency: ~2ms (first call ~8ms JIT warmup, code diff with 4 lines ~32ms).

Gotchas:

• Line-level only: no word-level or character-level diff mode. To highlight intra-line changes, you must post-process del/add pairs yourself.
• No context window option: unified output includes ALL lines (no -U3 style context limiting). For large files, the output can be very long.
• No file-level diff: operates on strings only. To diff files, read them into strings first.
• Empty string edge case: an empty original produces {op:"del",text:""} — the empty line is treated as a deleted line, which may look odd in processing pipelines.