HelloBuffCap

A lean buff-cap tracker for WoW Classic Era. Shows how many of your 32 helpful aura slots are in use — including the ones that never draw an icon — and which aura the game will push off next.

Written as a replacement for BCT, which stopped working when patch 1.15.9 moved Classic Era onto the modern UI codebase and turned UnitBuff and friends into deprecation shims.

Heads up — this is a personal work in progress. I build and evolve it as I play using it, so features land when I need them and design choices reflect my play style.

What it shows

BUFF CAP  27/32
NEXT MONGOOSE ELIXIR

That's the whole display. It sits locked in the bottom-left corner by default — /hbc unlock to drag it somewhere else. NEXT is your oldest-applied aura — the likeliest thing to go when a 33rd buff lands on you. Likeliest, not certain: see the caveats below. There is no buff list, by design.

Some auras hold a slot without being things the cap can take from you, so they count but are never nominated as NEXT:

No duration and already up at login — paladin auras, hunter aspects, druid forms, a stored Chronoboon.
Auras that never draw an icon — warrior stance, tracking, defensive state.

/hbc scan prints the full ordering to chat when you want to check what the addon thinks is happening.

Commands

Command	Effect
`/hbc`	Show / hide the HUD
`/hbc config`	Open the options panel
`/hbc lock` · `/hbc unlock`	Lock the HUD in place (locked also means click-through)
`/hbc resetpos`	Move the HUD back to the bottom-left corner
`/hbc reset`	Reset every setting (asks first)
`/hbc scan`	Dump the full aura list and its application times to chat

Caveats

Only works on Classic Era, no support for other game versions.
The queue is age-ordered, but the game also weighs importance. Patch 1.13.7 added buff prioritization so that "limited-duration or low impact buffs such as Renew, Rejuvenation, or 6-piece set bonuses" no longer push off "important buffs such as Rallying Cry of the Dragonslayer or Flask of the Titans". Blizzard never published the priority function, so it can't be reproduced. Age is still the best single signal — and it's what BCT and the buff-cap calculators use — but read position 1 as "oldest", not as a guarantee.
The hidden-aura count is a lower bound. Some auras take a slot without ever drawing an icon, and there is no API that lists them. HelloBuffCap detects the three it can see reliably: warrior stance, warrior defensive state and tracking. See DESIGN.md for which ones were deliberately left out and why.
Auras with no duration that were already active when you logged in can't be dated, so they sort to the back of the queue and are marked with ~. That covers paladin auras, hunter aspects, druid forms and a stored Chronoboon — which does take a slot, but collapses every world buff inside it into that one slot, so it's the last thing you want called out as about to drop.