Mewgenics Breeding Manager

External roster, breeding, and planning tool for Mewgenics.

It reads your save, shows the cats in a sortable live table, and adds planning views for safe breeding, room assignment, lineage, and long-term perfect-stat progression.

What It Does

• Live-loads Mewgenics saves and refreshes when the save changes
• Shows all cats with base stats, abilities, mutations, relationships, and lineage context
• Compares breeding pairs with offspring stat ranges, inheritance odds, and breakpoint hints
• Parses lovers and haters and uses them in optimizer logic
• Loads ability and mutation descriptions from resources.gpak when available
• Helps plan toward perfect 7-base-stat lines with staged pairing guidance

---

Main Roster | Single Cat View | Breeding Comparison | Room Optimizer | Perfect 7 Planner | Mutation & Disorder Planner | Family Tree | Safe Breeding | Breeding Partners | Exceptional Cats | Donation Cats | Calibration

---

Main Features

Main Roster

• Sortable and searchable table for your cats
• Click BL and MB cells directly to toggle breeding blacklist and must-breed priority
• Risk% can show inbreeding risk relative to the selected cat
• [EXC] exceptional breeder
• [DON] donation candidate

Current documented thresholds:

• Exceptional breeder: base stat sum >= 40
• Donation candidate heuristic:
  • base stat sum <= 34, and/or
  • top base stat <= 6, and/or
  • high aggression
  • must-breed and exceptional cats are excluded from donation marking

Single Cat Detail View

• Base / mod / total stat grid
• Ability chips with inline effect descriptions
• Mutation chips with inline effect descriptions
• Equipment
• Parents / grandparents
• Lovers / haters
• Include-in-breeding and must-breed controls

Breeding Comparison View

Select two compatible cats to open pair mode.

It shows:

• parent base stats
• offspring stat ranges
• inherited trait ranges
• ability / passive inheritance estimates
• stimulation-adjusted source weighting
• breakpoint hints:
  • locked 7s
  • stats that can hit 7 now
  • one-step-off stats
  • stalled stats
• appearance preview from parsed visual/body data

Room Optimizer

Optimizer for room placement and pair-quality planning.

Current controls include:

• minimum base stat sum
• maximum inbreeding risk
• mode toggle for pair quality vs family separation
• Minimize Variance
• Avoid Lovers
• Prefer Low Aggression
• Prefer High Libido

Current behavior includes:

• avoids hater conflicts
• can avoid lover conflicts
• prefers mutual lovers when appropriate
• uses parsed lovers / haters during placement
• shows per-room pair breakdowns with projected offspring ranges

Perfect 7 Planner

Dedicated long-term planner for building perfect cats.

This is separate from the Room Optimizer because it plans across generations instead of just placing current cats into rooms.

Controls:

• minimum base stat sum
• maximum inbreeding risk
• number of starting pairs
• stimulation
• avoid lovers
• prefer low aggression
• prefer high libido

Output is staged:

1. foundation pairs to start with
2. child separation guidance
3. rotation / outcross guidance
4. finish-and-maintain guidance

Stage 1 and Stage 3 show pair grids with:

• parent stats
• offspring ranges
• expected values
• breakpoint-oriented reasoning

Mutation & Disorder Breeding Planner

Dedicated view for planning breeding around specific mutations, disorders, and passives.

Features:

• Target Trait dropdown with search filtering — select a mutation, passive/disorder, or ability to plan for
• Shows all carriers of the selected trait with name, gender, age, and room
• Explains inheritance mechanics for the trait type (mutations, passives/disorders, abilities each inherit differently)
• Recommends breeding pairs prioritizing carrier x carrier matches, with inbreeding warnings
• Pair comparison mode — Ctrl+click two cats to see full breeding outcome analysis:
  • disorder inheritance odds (15% flat per parent, ~27.75% if both carry it)
  • birth defect risk based on inbreeding coefficient
  • visual mutation inheritance per body part with stimulation weighting
  • passive and spell inheritance odds
  • stat inheritance comparison with better-stat weighting
  • lineage info with grandparent passives
• Room filter and stimulation slider adjust all displayed odds

Note: the save data does not distinguish passives from disorders — all passive_abilities entries are shown together. Refer to in-game knowledge to identify which are disorders.

Safe Breeding View

Ranks valid partners for the selected cat by breeding safety.

Shows:

• partner
• inbreeding risk
• shared ancestors
• plain-language inbreeding labels

Breeding Partners View

Dedicated view for mutual-lover pairs.

Useful for:

• seeing who is bonded
• spotting room mismatches
• keeping breeding partners together

Family Tree View

Visual lineage browser for a selected cat.

Shows:

• self
• parents / grandparents
• children / grandchildren

Exceptional Cats view

Sidebar filter for viewing cats marked as exceptional breeders.

Threshold:

• base stat sum >= 40

Donation Candidates View

Sidebar filter for viewing cats marked as donation candidates.

Heuristic for donation marking:

• base stat sum <= 34, and/or
• top base stat <= 6, and/or
• high aggression
• must-breed and exceptional cats are excluded from donation marking

Calibration View

Per-save parser override editor for alive cats.

Can override:

• gender
• age
• aggression
• libido
• inbredness
• base stats

Also exposes parser-research fields such as:

• voice token
• pre-gender u32 values

Supports:

• save
• reload
• export calibration JSON
• import calibration JSON

Locations Settings

Settings -> Locations... lets you inspect and change:

• game install folder / resources.gpak
• save root directory

The app first checks common Steam install paths, then other discovered locations, then prompts when it still cannot find the game data.

Mutation / Ability Support

The app now parses and displays:

• active abilities
• passive abilities
• visual mutations
• relationship data

When resources.gpak is available, it also loads:

• ability descriptions
• passive descriptions
• mutation descriptions

The visual mutation parser uses slot-aware extraction rather than the old generic placeholder approach, so mutation output should now match the game much more closely.

Save / Parser Notes

The parser currently includes support for:

• room / alive / gone state
• parents and child links
• lovers / haters
• visual mutation slots
• personality fields:
  • aggression
  • libido
  • inbredness
• calibration overrides

Ongoing parser-research tooling is included under:

• tools/field_mapper/README.md

That toolkit supports bulk save ingestion, CSV labeling, and reverse-engineering workflows for unresolved fields like sexuality/gayness.

Requirements

• Python 3.11+
• PySide6
• lz4

Installation

git clone https://github.com/frankieg33/MewgenicsBreedingManager
cd MewgenicsBreedingManager
pip install -r requirements.txt
python mewgenics_manager.py

On Windows you can also build a standalone executable with build.bat.

Usage

By default the app looks for saves under:

%APPDATA%\Glaiel Games\Mewgenics\<SteamID>\saves\

Useful controls:

• File -> Open Save File...
• F5 reload
• Settings -> Show Family Tree & Inbreeding
• Settings -> Locations...
• Ctrl+=, Ctrl+-, Ctrl+0 for zoom

Inbreeding / Risk Calculation

Risk% is based on Wright's Coefficient of Inbreeding using parsed ancestor paths.

High level:

1. Build ancestor paths for each cat
2. Find shared ancestors
3. Reject invalid path combinations that reuse the same cat improperly
4. Sum valid path contributions
5. Normalize to a capped percentage for display

This is useful, but still experimental for very complex pedigrees.

Known Limits

• Some parser-derived fields are still under active research
• Sexuality / gayness is not fully mapped yet
• Ability / mutation text quality depends on available game data
• Inbreeding and family analysis are good enough to use, but should still be treated as save-research features rather than absolute ground truth

Changelog

1.7.0 lots of new features. perfect 7 planner. added a filter for exceptional cats and for donation candidates. performance optimization. lots of suggestions from Daedmano. 1.6.0 fixed mutations and a few other bugs. thanks to byronaltice. 1.5.0 tagged cats in game are now taken into account, which should fix gender going forward. 1.4.0 added an override ability for gender 1.3.1 added a blacklist to the room optimization view 1.3.0 added detail to the room optimizer 1.2.0 added a room optimizer thanks to ICaxapI 1.1.0 updated the gender logic thanks to heartskingu

Credits

• Save parsing research based on pzx521521/mewgenics-save-editor
• Additional community save-format research and issue reports from players and mod users