2E Target 20 is a focused Fantasy Grounds Unity extension for the official AD&D 2nd Edition (2E) ruleset. It modernizes ability checks and skill/proficiency checks by converting them from the traditional roll-under mechanic to a clean, unified d20 + modifiers ≥ 20 system—while leaving attacks, saving throws, and percentile skills completely untouched.

The New Formulas

• Ability Checks: d20 + Table 44 ability modifier + character level ≥ 20
• Skill/Proficiency Checks (ability-linked only): d20 + Table 44 ability modifier + character level + (Class + Stat + Racial + Armor + Skill + Miscellaneous modifiers) ≥ 20

Table 44 comes straight from Player's Option: Skills & Powers (p.89) — a compact, bounded modifier table that replaces raw 3–18 ability scores:

Character level is added flat and uncapped, giving high-level characters strong reliability on trained checks (echoing the spirit of 5E proficiency scaling). All skill modifier fields are the exact ones already present on stock skill records—no new bookkeeping required.

Smart Implementation

• Ability Checks: Uses ActionsManager mod/result handlers. Preserves existing CHECK-effect bonuses (e.g., temporary spells granting "+2 to Strength checks").
• Skill Checks: Monkey-patches ActionSkill.getRoll (the only point with direct access to the skill’s database node) to compute the full bonus from individual fields, then sets a flat Target 20. A no-op mod handler prevents stock roll-under logic from interfering.
• Chat Feedback: Success/failure messages clearly show “(vs. Target 20) [SUCCESS by X]” or “[FAILURE by X]” with appropriate fonts and icons.
• Safe Guards: Only activates on single d20 rolls. Fully respects the “AD&D Options and House Rules” extension’s 3d6/4d6 ability check modes (does nothing, letting the other extension handle it).

Percentile skills (thief skills, etc.) and all roll-under d100 mechanics remain unchanged.

Seamless Composition

Exposes Target20Manager.isActive() for other extensions to detect. Works beautifully with 2E ADV/DIS—when Target 20 is active, Advantage/Disadvantage treats ability/skill checks as roll-over (keep the higher die), eliminating the need for manual inversion. No dependency required either way.

Known Limitation

Skill checks do not currently incorporate magical CHECK/SKILL effect-tag bonuses (a complexity tradeoff in v1.0 due to how bonuses are gathered). Ability checks fully support them. This may be revisited based on play feedback.

Compatibility

• Official AD&D 2nd Edition ruleset.
• Purely additive—no stock ruleset files edited.
• Works alongside other 2E extensions (including ADV/DIS and options modules).
• Load order set conservatively at 10.