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Fantasy Solvers – Balatro Lab

by balatro.fantasysolvers.com · remote · no sign-in to list tools · v0.1.0 · published by com.fantasysolvers.balatro

Supported Balatro scoring and exact small-deck play/discard analysis with verified explanations.

Changes · 2
CompareRegistry entry

4 tools: 2 change things and 2 only read.

Scanned Oct 21, 2026

1 check matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http balatro-lab https://balatro.fantasysolvers.com/mcp

Findings

Matches of fixed checks, with the text they matched.

1 warn
  • Warnevaluate_hand

    The server marks "evaluate_hand" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The name "evaluate_hand" says "evaluate": a word for a change.

    What this check looks for

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

4 tools

Changes things 2Claude Code: ask
  • evaluate_handVersioned optimized immediate score from bengine-core.1 finding

    Why it is in this group

    • The name "evaluate_hand" says "evaluate": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

      The server marks "evaluate_hand" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The name "evaluate_hand" says "evaluate": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Versioned optimized immediate score from bengine-core. Played and held order is optimized, not evaluated literally. Unsupported effects are rejected.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
    • readOnlyHint: true
  • recommend_actionExact small-deck mathematical action values under optimal continuation in the supported model, not estimated real-game success.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Exact small-deck mathematical action values under optimal continuation in the supported model, not estimated real-game success. Returns all optimal ties and fully reconciled draw explanations; no recommendation on incomplete jobs. No A2/full-deck sampling.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
    • readOnlyHint: true
Only reads 2Claude Code: allow
  • compare_actionsCompare all immediate plays or exact small-deck play/discard values, with the same contract and validation as HTTP.No findings

    Why it is in this group

    • The name "compare_actions" says "compare": a word for reading.
    Description, as the server wrote it
    Compare all immediate plays or exact small-deck play/discard values, with the same contract and validation as HTTP. Exact mode limits: 12 draw cards, two hands, two discards. Select explain_actions for particular branches.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
    • readOnlyHint: true
  • get_solver_capabilitiesEngine/rules/build identity, contract version, supported effects, assumptions and limits.No findings

    Why it is in this group

    • The name "get_solver_capabilities" says "get": a word for reading.
    Description, as the server wrote it
    Engine/rules/build identity, contract version, supported effects, assumptions and limits.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
    • readOnlyHint: true

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Install

Pinned to version 0.1.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http balatro-lab https://balatro.fantasysolvers.com/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__balatro-lab__compare_actions",
      "mcp__balatro-lab__get_solver_capabilities"
    ],
    "ask": [
      "mcp__balatro-lab__evaluate_hand",
      "mcp__balatro-lab__recommend_action"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as balatro-lab. Review it before you use it.