Iron's Spellbooks Tweaks

Iron's Spellbooks Tweaks

Modpack config tweaks for Iron's Spells 'n Spellbooks. TOML options for mana, cooldowns, spell power and buff durations, dimension blocks, rarity gating, inscriptions, black hole resistance. Per-world overrides and datapack unlocks. Soft dep, no mixins.

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About this Mod

Iron's Spellbooks Tweaks

Config tweaks for Iron's Spells 'n Spellbooks. Adds TOML config options that Iron's doesn't expose.

What it does

Iron's Spellbooks has a small set of config options in its serverconfig (mana regen multiplier, spawn percent, sword toggles). Several open issues on iron431's GitHub ask for more direct control over mana regen rate, starting mana, and cooldowns (#161, #162, #391) that haven't been addressed.

This addon fills those gaps without touching Iron's serverconfig (which has known multiplayer sync bugs per #1033). It uses its own TOML at config/irons_spellbooks_tweaks-server.toml and applies settings via attribute modifiers and hooks on Iron's public events.

Config options

Mana

baseManaRegenPercent: bonus added to MANA_REGEN attribute on login
startingMaxMana: bonus added to MAX_MANA attribute on login
disableManaRegen: fully disables passive mana regen

Spell timing

cooldownReductionBonus: bonus to COOLDOWN_REDUCTION attribute
castTimeReductionBonus: bonus to CAST_TIME_REDUCTION attribute

Spell scaling

spellPowerMultiplier: scales the SPELL_POWER attribute on every player, range 0.0 to 10.0. Damage tooltips reflect the scaled value.
buffDurationMultiplier: scales buff and debuff durations from Iron's Spellbooks and its addons, range 0.0 to 10.0. Vanilla potions, food effects, and beacon effects are not touched. The active effect countdown in inventory shows the actual time, the spell tooltip shows the unmodified base.
buffDurationNamespaces: list of mod namespaces whose effects get scaled by buffDurationMultiplier. Defaults cover Iron's Spellbooks plus Cataclysm Spellbooks, dacxirons, GameTechBC's Spellbooks, GTBC's Geomancy Plus, Hazen 'n Stuff, Illage and Spell-age, and Traveloptics.

Restrictions

spellCastingDisabledDimensions: list of dimension IDs where casting is blocked
maxSpellRarity: caps the highest spell rarity players can cast (mob casters bypass)
inscriptionBlacklist: list of spell IDs that cannot be inscribed

Black hole

blackholeImmunity: per-entity-type pull resistance values from 0.0 to 1.0

Summon scaling

summonVexHpMultiplier, summonVexDamageMultiplier: scale HP and damage of summoned vexes
raiseDeadHpMultiplier, raiseDeadDamageMultiplier: scale HP and damage of summoned skeletons and zombies from Raise Dead
summonPolarBearHpMultiplier, summonPolarBearDamageMultiplier: scale HP and damage of summoned polar bears
summonHorseHpMultiplier: scale HP of summoned horses
summonSwordsDamageMultiplier: scale damage of Summon Swords

Multipliers stack multiplicatively with any HP/damage scaling other mods apply.

Per-world config overrides (v1.5+)

The global config in config/ is the source of truth. To customize a specific world, drop a copy of the global file into that world's serverconfig/ folder and edit it. Missing keys fall back to global.

The /isstweaks copyconfig command (op-only) copies the global config into the current world's serverconfig/ folder so you can set up overrides in-game. It won't overwrite an existing per-world file.

Per-player progression unlocks

A datapack-driven unlock system lets pack devs gate spells, dimensions, and bonuses behind advancements or boss kills. JSONs go at data//isstweaks/unlocks/.json. Supports advancement and entity_kill triggers.

Available grants:

rarity_cap: raise the player's allowed rarity ceiling above the global maxSpellRarity gate
cooldown_reduction_bonus: flat addition to the player's cooldown reduction attribute
cast_time_reduction_bonus: flat addition to the player's cast time reduction attribute
max_mana_bonus: flat int addition to the player's MAX_MANA attribute
mana_regen_bonus: flat addition to the player's MANA_REGEN attribute
remove_dimensions: exempt the player from the casting dimension blacklist for these dimensions
remove_inscriptions: exempt the player from the inscription blacklist for these spells

If a player gets multiple unlocks that grant the same number bonus, they all add up. Negative values work too if you want to subtract. There's an optional requirement_text field on each unlock JSON for a hint string, which the requirements command shows in chat.

Commands

OP only:

  • /isstweaks grant : manually grant an unlock
  • /isstweaks revoke : revoke from the granted set
  • /isstweaks status : show current progress
  • /isstweaks reset : wipe all progression data
  • /isstweaks copyconfig: copy the global config into the current world's serverconfig folder

Open to all players:

  • /isstweaks requirements spell : shows the unlock requirement for a specific spell. Prefixed with [Unlocked] if the player has already met it.
  • /isstweaks requirements rarity : shows the unlock requirement for a rarity tier. Same [Unlocked] indicator when the player's cap is at or above the queried tier.

Note on overlap with Iron's per-spell configs

Iron's Spellbooks has per-spell JSON configs at config/irons_spellbooks_spell_config/ for tweaking individual spells (max level, mana cost multiplier, cooldown). This mod doesn't touch those. The maxSpellRarity option is just one rarity gate that applies to every spell at cast time, no per-spell editing needed. It's faster to set up but less precise than per-spell tweaking. Pick whichever fits, or use both together.

For modpack makers

Drop the jar in your pack's mods folder, edit config/irons_spellbooks_tweaks-server.toml, ship the config alongside the pack. All options are server-side so clients don't need matching configs.

##Compatibility

Minecraft 1.20.1 Forge and Minecraft 1.21.1 NeoForge
Iron's Spells 'n Spellbooks 3.0.0+ (1.20.1) or 1.21.1-3.15.0+ (1.21.1)
Soft dependency, mod loads cleanly without Iron's Spellbooks present
No conflicts expected with other Iron's addons

License

MIT

Available Versions

Iron's Spellbooks Tweaks 1.5.0 - NeoForge 1.21.1release
MC 1.21.1neoforge
June 10, 2026
Iron's Spellbooks Tweaks 1.5.0 - Forge 1.20.1release
MC 1.20.1forge
June 10, 2026

How to Install Iron's Spellbooks Tweaks on Your Server

1

Order Server

Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).

2

Set forge Loader

In the panel under "Egg", select the forge loader and matching Minecraft version (1.21.1).

3

Install Mod

Open the mod browser in the dashboard and search for "Iron's Spellbooks Tweaks". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.

Compatibility

Mod Loaders

forgeneoforge

Minecraft Versions

1.21.1, 1.20.1

Server-side

Required

Recommended RAM

4 GB(min. 3 GB)

Frequently Asked Questions

Iron's Spellbooks Tweaks server crashes on startup – what to do?

Most common cause: wrong forge version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.21.1). You can switch loaders with one click in the panel.

Is Iron's Spellbooks Tweaks compatible with forge and neoforge?

Iron's Spellbooks Tweaks officially supports forge, neoforge for Minecraft 1.21.1, 1.20.1. The Mado dashboard automatically detects incompatible loader combinations.

Server lagging with Iron's Spellbooks Tweaks – how to optimize performance?

Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Iron's Spellbooks Tweaks consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.

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Details

License
MIT License
Server-side
Required

Supported Versions

1.21.11.20.1