Arts command gauge - weapon-specialty arm width

At a glance

Cost byte

Runtime command record DAT_801C9360[char][cmd] + 0x74 - one byte is both the AP price and the pennant width

Budget

The character's AGL stat seeds the turn pool at ctx+0x6DC; input ends when the next command would not fit

Disc source

The equipped weapon's section in the character's player battle file (extraction 863..866), copied verbatim at battle load

Tiers

30 favored / 42 off-class / 54 far tier - authored data, no class comparison in code

Editor

The ROM patcher's equipment editor and the randomizer's --weapon-specialty rewrite these bytes in place

Confidence

Confirmed - live-pinned and byte-validated against the disc; "command 0x0C = the arm" is Inferred (how we know)

What the AP bar does

On your turn the Arts bar fills with a row of pennants, one per direction you press, and stops accepting input when the next pennant would not fit. Every direction has a price; three of the four never change. The fourth - the weapon-hand swing - is authored per weapon, and because the price is also the pennant's width, an off-class weapon looks wider and fits fewer commands in the same turn.

Only the weapon hand depends on equipment - Left for Vahn and Gala, Right for Noa. The Ra-Seru arm and the two leg commands are always 30. The "off-class doubles the arm" folklore counts penalties: the Astral penalty (+24) is twice the off-class penalty (+12); the cost itself is ×1.4, not ×2.

How the gauge consumes it

The gauge is assembled by the battle action handler; one case reads the cost, another spends it:

// gauge build (case 9 / 0x2C)
cost = command_record[cmd] + 0x74;    // the arm width / AP cost byte
gauge_slot.width = cost - 6;          // visual width on the bar

// press (case 0xB)
if (pool < cost) return;              // not enough AP - input ends
pool -= cost;                         // ctx+0x6DC, seeded from AGL

One byte is both price and width - a larger button and a more expensive command are the same value. The pennant is a text window and its label has to fit: 30 is retail's floor, 24 is still legible, below that the label smears (the patcher refuses costs below 24). Two neighbours share the machinery:

• The Muscle Dome hand deals and spends the same records: a dome card is a direction command, its cost is the same byte, the commit debits the same pool (minigames).
• The enemy analogue: a monster fills its per-turn action queue by paying each move's +0x74 cost out of its per-round AGL gauge - the same "wider cost = fewer commands" mechanic on the AI side (battle action).

Where the cost comes from

The game performs no class comparison. The cost is written once at battle load as a verbatim 43-word block copy out of the assembled battle-character buffer - no arithmetic between load and store, confirmed by a live write-watch across a field→battle transition. The source is the equipped weapon's section of the character's player battle file:

section (LZS-decoded)
  +0x04  u32 swing_rec   ; offset to the swing/arm command record
  swing_rec + 0x74       ; u8 arm cost  ← the weapon-specialty byte

The descriptor table keys sections by item id, so each weapon has its own swing record per character's file - a claw is cheap in Noa's file and expensive in Gala's. Decoding all four files gives the byte-exact picture:

Cross-checked live: Gala + Nail Glove reads 42, Gala + Ra-Seru Club reads 30, matching his file's sections. The cost lives inside an LZS-compressed stream, so an editor decompresses the section, rewrites one byte, recompresses, and writes back within the slot footprint.

"Off-class" itself is legible from the static item records: the description pointer is shared per weapon class and carries a Best:<character> token - knife/sword → Vahn, claw → Noa, club/axe → Gala. The Astral Sword has its own description, matches no character, and simply sits on the tier Noa reaches with any club.

Every weapon, every character

Weapon-hand swing cost from each character's file; all other commands read 30. A dash means the file has no section for the weapon (the equip mask stops them equipping it anyway). Classes are finer than blade / claw / club: Gala swings a Short Sword at 30 but a knife at 42; Vahn swings light clubs at 30 but the Power Club and every axe at 42.

Status limb gating

A Rot-class status grays individual command arrows and refuses their input. The gray-draw pass and the input gate read the same status bits, bit-for-bit - and the retail assignment is not one bit per arrow:

With all three limb bits set, Attack is unusable. Rot rolls exactly one of the three limb bits per application.

At execution: a different weapon read

Once a combo is committed, the execution resolver replays it one command per step and folds half the equipment slot's attack into the working ATK per swing - a read distinct from the gauge cost, covered in full on battle formulas. The battle loader deliberately folds no ATK at load; the fold happens here, per committed command.

Common misconceptions

How we know

The full doc adds the gauge pool's AGL seed and Spirit refill, what a named art costs and where it is charged, the arts-AP override hook, and the port's input session: docs/subsystems/arts-command-gauge.md.

See also