Map the shared turn instead of drafting four isolated piles. Pick 2 to 4 characters, lock in the core cards, and check where the team actually hands pressure from one seat to the next.
The Planner Reads Shared Windows, Not Four Separate Decklists
This page is for team handoff questions: who frontloads, who fixes the debuff window, and which seat can actually pass value instead of pretending every strong card is team play.
When It Helps
Use it when the table plan matters more than one seat
It helps when you already know the active characters and the core cards that define each seat, and the real question is whether the team windows actually connect.
Where It Lies
Core picks are signals, not complete decks
If the rest of the list, relic bar, or shop economy is doing the real work, the planner can overrate a clean support story that the full run never cashes in.
Input Boundary
Two to four seats, core cards, and tradeable relic ideas only
The planner models team size, seat identity, selected core cards, and relic handoff suggestions. It does not know every future pick, event, or gold spend.
How It Works
How the Co-op Synergy Planner Reads Your Team
This planner maps the core cards from each seat against shared coverage categories, then surfaces the windows where two players can combine actions and the chains where one seat enables another. It focuses on handoff timing and role overlap rather than individual card power.
Reviewed2026-03-29
How to Use It
Enter 2 to 4 seats, pick core cards for each, then read the team windows
Start by selecting the number of players and assigning a character to each seat. Then enter the core cards that define what each seat is actually trying to do. You do not need a full decklist — three to five cards that describe the seat's real role are enough for the planner to build meaningful coverage and handoff analysis.
After entering the seats, the Team Readout and Shared Windows panels show where the team connects. If the Shared Windows section is sparse, the seats are probably playing four isolated single-player plans rather than a co-op team.
The Coverage Map panel shows which damage types, debuff categories, and defensive roles the team currently covers and which are missing.
The Support Chains panel shows which seat enables which, based on debuff application, block generation, and shared draw.
The Relic Suggestions panel identifies relics worth handing across seats given the current team composition.
What It Models
Coverage overlap, handoff windows, and support chain direction
The planner scores each seat's core cards against a set of coverage categories, then computes the pairwise overlap between seats. Shared windows are turns where two seats can act on the same enemy state — one applies a debuff, the other capitalizes on it — based on the card tags in the entered core sets.
This is a structural analysis, not a damage simulation. It tells you where the team design is coherent and where it has gaps, not whether the exact damage numbers are sufficient.
Where It Stops
Full decklists, future picks, and exact combat scripting are outside the model
The planner models core card signals, not complete decklists. Cards outside the entered core set do not affect the output. Future draft picks, event results, or shop purchases that change the team composition will require a fresh entry to reflect the updated state.
Maintenance Signals
Who Maintains This Page
A calculator without ownership is just a fancy guess. These signals show who maintains the tool, which live ruleset it matches, and where the responsibility boundary stops.
Maintained bySTS2 Calculator Tools Desk
Independent fan-made editors and data maintainers. This is not an official Slay the Spire 2 or Mega Crit property.
Responsible editorSTS2 Calculator Site Operator
Final site operator and responsible editor. Final contact for corrections, rights notices, and maintenance triage via shwuhen@gmail.com.
Last reviewedMarch 28, 2026
Visible copy, links, and page-level signals were checked in the latest review pass.
Patch verifiedCurrent Early Access co-op synergy set
If a patch moves the numbers, wording, or assumptions behind this page, the page gets revised, narrowed, or rechecked again.
Applies toTeam-window, support-chain, and relic-routing notes exposed by the character and card inputs on this planner.
Tool pages cover the math, tables, and assumptions surfaced by the current UI on this route.
DisclaimerTool output is only as honest as the current inputs and published assumptions.
Bad inputs, hidden fight modifiers, or unsupported edge cases still produce bad conclusions. The tool does not guess those for you.
