Compression Language Packs

Compression Language Packs

Caveman compression can load language-specific rule packs in addition to the built-in English rules. This keeps the core engine stable while allowing Portuguese, Spanish, German, French, Japanese, and future language packs to evolve independently.

Location

Language packs live under:

open-sse/services/compression/rules/<language>/

Current shipped packs (verified against rules/ directory contents):

Language	Directory	Rule categories present
English	rules/en/	context, dedup, filler, structural, ultra
Spanish	rules/es/	context, dedup, filler, structural, ultra
Portuguese (Brazil)	rules/pt-BR/	context, filler, structural
German	rules/de/	context, filler, structural
French	rules/fr/	context, filler, structural
Japanese	rules/ja/	context, filler, structural

Parity note: en and es packs have the full 5 categories; pt-BR, de, fr, ja ship 3 categories. The missing dedup and ultra categories silently fall back to the English built-ins. Contributions welcome to add dedup.json and ultra.json for the smaller packs.

The canonical category list and per-category schema live in open-sse/services/compression/rules/_schema.json (JSON Schema draft 2020-12).

Language Detection

languageDetector.ts uses lightweight heuristics to infer the language from prompt text. The configured default language is still respected, and detection can be disabled by config when exact control is required.

Detection output is used only to choose rule packs. It does not change provider routing, locale selection, or UI language.

Config Shape

Compression settings can include:

{
  "languageConfig": {
    "enabled": true,
    "defaultLanguage": "en",
    "autoDetect": true,
    "enabledPacks": ["en", "pt-BR", "es", "de", "fr", "ja"]
  },
  "cavemanConfig": {
    "language": "en",
    "autoDetectLanguage": true,
    "enabledLanguagePacks": ["en", "pt-BR", "es", "de", "fr", "ja"]
  }
}

languageConfig controls dashboard/preview defaults. cavemanConfig is the runtime engine config used when Caveman compresses message text.

Adding a Language Pack

1. Create open-sse/services/compression/rules/<language>/<pack>.json.
2. Use the Caveman rule format from docs/compression/COMPRESSION_RULES_FORMAT.md.
3. Keep replacements conservative and avoid changing code, identifiers, URLs, or JSON.
4. Add or update tests for language selection and replacement behavior.
5. Expose new dashboard/i18n labels if the language appears in UI selectors.

API

Available packs can be queried with:

curl http://localhost:20128/api/compression/language-packs

The preview endpoint accepts language config overrides:

curl -X POST http://localhost:20128/api/compression/preview \
  -H "Content-Type: application/json" \
  -d '{
    "mode": "standard",
    "text": "Por favor, eu gostaria que voce basicamente resumisse isso.",
    "config": {
      "languageConfig": {
        "defaultLanguage": "pt-BR",
        "autoDetect": true
      }
    }
  }'

SHARED_BOUNDARIES (v3.8.0)

All 6 language packs received a SHARED_BOUNDARIES clause in v3.8.0 that is applied at every Caveman intensity (LITE, FULL, ULTRA). It instructs the engine to preserve these patterns verbatim, regardless of surrounding filler removal:

Pattern type	Example
Fenced code blocks	```python\n...\n```
Inline code	`my_var`
URLs	https://example.com/path
File paths (absolute + relative)	/etc/hosts, ./src/index.ts
Error headers	Error:, TypeError:, SyntaxError:
Stack trace lines	at functionName (file.ts:12:3)

These patterns are populated in DEFAULT_CAVEMAN_CONFIG.preservePatterns (previously []). The constant lives in open-sse/services/compression/types.ts.

Why this matters

Without SHARED_BOUNDARIES, aggressive Caveman modes could strip content that looked like repetitive prose but was actually a code snippet, file path, or error stack. SHARED_BOUNDARIES acts as a language-agnostic safety net applied before filler rules run.

Customizing preservePatterns

Additional patterns can be added at runtime via compression settings:

{
  "cavemanConfig": {
    "preservePatterns": [
      "```[\\s\\S]*?```",
      "`[^`]+`",
      "https?://\\S+",
      "(?:/|\\./)[^\\s]+",
      "\\b(?:Error|TypeError|SyntaxError|RangeError):",
      "\\s+at\\s+\\S+\\s+\\(\\S+:\\d+:\\d+\\)"
    ]
  }
}

Custom patterns extend (not replace) the 6 defaults.

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Operational Notes

• English built-in rules remain the fallback when a language pack is missing.
• Invalid built-in JSON packs fail validation so release assets do not silently degrade.
• Rule packs are data-only and should not import code or run arbitrary logic.
• The compression analytics layer records the selected mode and engine, not full prompt text.