Add Recall Knowledge DC and skill to PF2e stat blocks

Display Recall Knowledge line below trait tags showing DC (from level
via standard DC-by-level table, adjusted for rarity) and associated
skill derived from creature type trait. Omitted for D&D creatures and
creatures with no recognized type trait.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/components/__tests__/pf2e-stat-block.test.tsx

@@ -25,6 +25,12 @@ const ABILITY_MID_NAME_REGEX = /Goblin Scuttle/;
 const ABILITY_MID_DESC_REGEX = /The goblin Steps\./;
 const CANTRIPS_REGEX = /Cantrips:/;
 const AC_REGEX = /16/;
+const RK_DC_13_REGEX = /DC 13/;
+const RK_DC_15_REGEX = /DC 15/;
+const RK_DC_25_REGEX = /DC 25/;
+const RK_HUMANOID_SOCIETY_REGEX = /Humanoid \(Society\)/;
+const RK_UNDEAD_RELIGION_REGEX = /Undead \(Religion\)/;
+const RK_BEAST_SKILLS_REGEX = /Beast \(Arcana\/Nature\)/;
 
 const GOBLIN_WARRIOR: Pf2eCreature = {
 	system: "pf2e",
@@ -154,6 +160,53 @@ describe("Pf2eStatBlock", () => {
 		});
 	});
 
+	describe("recall knowledge", () => {
+		it("renders Recall Knowledge line for a creature with a recognized type trait", () => {
+			renderStatBlock(GOBLIN_WARRIOR);
+			expect(screen.getByText("Recall Knowledge")).toBeInTheDocument();
+			expect(screen.getByText(RK_DC_13_REGEX)).toBeInTheDocument();
+			expect(screen.getByText(RK_HUMANOID_SOCIETY_REGEX)).toBeInTheDocument();
+		});
+
+		it("adjusts DC for uncommon rarity", () => {
+			const uncommonCreature: Pf2eCreature = {
+				...GOBLIN_WARRIOR,
+				traits: ["uncommon", "small", "humanoid"],
+			};
+			renderStatBlock(uncommonCreature);
+			expect(screen.getByText(RK_DC_15_REGEX)).toBeInTheDocument();
+		});
+
+		it("adjusts DC for rare rarity", () => {
+			const rareCreature: Pf2eCreature = {
+				...GOBLIN_WARRIOR,
+				level: 5,
+				traits: ["rare", "medium", "undead"],
+			};
+			renderStatBlock(rareCreature);
+			expect(screen.getByText(RK_DC_25_REGEX)).toBeInTheDocument();
+			expect(screen.getByText(RK_UNDEAD_RELIGION_REGEX)).toBeInTheDocument();
+		});
+
+		it("shows multiple skills for types with dual skill mapping", () => {
+			const beastCreature: Pf2eCreature = {
+				...GOBLIN_WARRIOR,
+				traits: ["small", "beast"],
+			};
+			renderStatBlock(beastCreature);
+			expect(screen.getByText(RK_BEAST_SKILLS_REGEX)).toBeInTheDocument();
+		});
+
+		it("omits Recall Knowledge when no type trait is recognized", () => {
+			const noTypeCreature: Pf2eCreature = {
+				...GOBLIN_WARRIOR,
+				traits: ["small", "goblin"],
+			};
+			renderStatBlock(noTypeCreature);
+			expect(screen.queryByText("Recall Knowledge")).not.toBeInTheDocument();
+		});
+	});
+
 	describe("perception and senses", () => {
 		it("renders perception modifier and senses", () => {
 			renderStatBlock(GOBLIN_WARRIOR);

apps/web/src/components/pf2e-stat-block.tsx

@@ -1,5 +1,5 @@
 import type { Pf2eCreature, SpellReference } from "@initiative/domain";
-import { formatInitiativeModifier } from "@initiative/domain";
+import { formatInitiativeModifier, recallKnowledge } from "@initiative/domain";
 import { useCallback, useRef, useState } from "react";
 import { SpellDetailPopover } from "./spell-detail-popover.js";
 import {
@@ -113,6 +113,8 @@ export function Pf2eStatBlock({ creature }: Readonly<Pf2eStatBlockProps>) {
 	);
 	const handleCloseSpell = useCallback(() => setOpenSpell(null), []);
 
+	const rk = recallKnowledge(creature.level, creature.traits);
+
 	const abilityEntries = [
 		{ label: "Str", mod: creature.abilityMods.str },
 		{ label: "Dex", mod: creature.abilityMods.dex },
@@ -147,6 +149,12 @@ export function Pf2eStatBlock({ creature }: Readonly<Pf2eStatBlockProps>) {
 				<p className="mt-1 text-muted-foreground text-xs">
 					{creature.sourceDisplayName}
 				</p>
+				{rk && (
+					<p className="mt-1 text-sm">
+						<span className="font-semibold">Recall Knowledge</span> DC {rk.dc}{" "}
+						&bull; {capitalize(rk.type)} ({rk.skills.join("/")})
+					</p>
+				)}
 			</div>
 
 			<SectionDivider />

packages/domain/src/__tests__/recall-knowledge.test.ts

@@ -0,0 +1,99 @@
+import { describe, expect, it } from "vitest";
+import { recallKnowledge } from "../recall-knowledge.js";
+
+describe("recallKnowledge", () => {
+	it("returns null when no type trait is recognized", () => {
+		expect(recallKnowledge(5, ["small", "goblin"])).toBeNull();
+	});
+
+	it("calculates DC for a common creature from the DC-by-level table", () => {
+		const result = recallKnowledge(5, ["humanoid"]);
+		expect(result).toEqual({ dc: 20, type: "humanoid", skills: ["Society"] });
+	});
+
+	it("calculates DC for level -1", () => {
+		const result = recallKnowledge(-1, ["humanoid"]);
+		expect(result).toEqual({ dc: 13, type: "humanoid", skills: ["Society"] });
+	});
+
+	it("calculates DC for level 0", () => {
+		const result = recallKnowledge(0, ["animal"]);
+		expect(result).toEqual({ dc: 14, type: "animal", skills: ["Nature"] });
+	});
+
+	it("calculates DC for level 25 (max table entry)", () => {
+		const result = recallKnowledge(25, ["dragon"]);
+		expect(result).toEqual({ dc: 50, type: "dragon", skills: ["Arcana"] });
+	});
+
+	it("clamps DC for levels beyond the table", () => {
+		const result = recallKnowledge(30, ["dragon"]);
+		expect(result).toEqual({ dc: 50, type: "dragon", skills: ["Arcana"] });
+	});
+
+	it("adjusts DC for uncommon rarity (+2)", () => {
+		const result = recallKnowledge(5, ["uncommon", "medium", "undead"]);
+		expect(result).toEqual({
+			dc: 22,
+			type: "undead",
+			skills: ["Religion"],
+		});
+	});
+
+	it("adjusts DC for rare rarity (+5)", () => {
+		const result = recallKnowledge(5, ["rare", "large", "dragon"]);
+		expect(result).toEqual({ dc: 25, type: "dragon", skills: ["Arcana"] });
+	});
+
+	it("adjusts DC for unique rarity (+10)", () => {
+		const result = recallKnowledge(5, ["unique", "medium", "humanoid"]);
+		expect(result).toEqual({
+			dc: 30,
+			type: "humanoid",
+			skills: ["Society"],
+		});
+	});
+
+	it("returns multiple skills for beast type", () => {
+		const result = recallKnowledge(3, ["beast"]);
+		expect(result).toEqual({
+			dc: 18,
+			type: "beast",
+			skills: ["Arcana", "Nature"],
+		});
+	});
+
+	it("returns multiple skills for construct type", () => {
+		const result = recallKnowledge(1, ["construct"]);
+		expect(result).toEqual({
+			dc: 15,
+			type: "construct",
+			skills: ["Arcana", "Crafting"],
+		});
+	});
+
+	it("matches type traits case-insensitively", () => {
+		const result = recallKnowledge(5, ["Humanoid"]);
+		expect(result).toEqual({ dc: 20, type: "Humanoid", skills: ["Society"] });
+	});
+
+	it("uses the first matching type trait when multiple are present", () => {
+		const result = recallKnowledge(7, ["large", "monitor", "protean"]);
+		expect(result).toEqual({
+			dc: 23,
+			type: "monitor",
+			skills: ["Religion"],
+		});
+	});
+
+	it("preserves original trait casing in the returned type", () => {
+		const result = recallKnowledge(1, ["Fey"]);
+		expect(result?.type).toBe("Fey");
+	});
+
+	it("ignores common rarity (no adjustment)", () => {
+		// "common" is not included in traits by the normalization pipeline
+		const result = recallKnowledge(5, ["medium", "humanoid"]);
+		expect(result?.dc).toBe(20);
+	});
+});

packages/domain/src/index.ts

@@ -108,6 +108,10 @@ export {
 	VALID_PLAYER_COLORS,
 	VALID_PLAYER_ICONS,
 } from "./player-character-types.js";
+export {
+	type RecallKnowledge,
+	recallKnowledge,
+} from "./recall-knowledge.js";
 export { rehydrateCombatant } from "./rehydrate-combatant.js";
 export { rehydratePlayerCharacter } from "./rehydrate-player-character.js";
 export {

packages/domain/src/recall-knowledge.ts

@@ -0,0 +1,118 @@
+/**
+ * PF2e Recall Knowledge DC calculation and type-to-skill mapping.
+ *
+ * DC is derived from creature level using the standard DC-by-level table
+ * (Player Core / GM Core), adjusted for rarity.
+ */
+
+/** Standard DC-by-level table from PF2e GM Core. Index = level + 1 (level -1 → index 0). */
+const DC_BY_LEVEL: readonly number[] = [
+	13, // level -1
+	14, // level 0
+	15, // level 1
+	16, // level 2
+	18, // level 3
+	19, // level 4
+	20, // level 5
+	22, // level 6
+	23, // level 7
+	24, // level 8
+	26, // level 9
+	27, // level 10
+	28, // level 11
+	30, // level 12
+	31, // level 13
+	32, // level 14
+	34, // level 15
+	35, // level 16
+	36, // level 17
+	38, // level 18
+	39, // level 19
+	40, // level 20
+	42, // level 21
+	44, // level 22
+	46, // level 23
+	48, // level 24
+	50, // level 25
+];
+
+const RARITY_ADJUSTMENT: Readonly<Record<string, number>> = {
+	uncommon: 2,
+	rare: 5,
+	unique: 10,
+};
+
+/**
+ * Mapping from PF2e creature type traits to the skill(s) used for
+ * Recall Knowledge. Types that map to multiple skills list all of them.
+ */
+const TYPE_TO_SKILLS: Readonly<Record<string, readonly string[]>> = {
+	aberration: ["Occultism"],
+	animal: ["Nature"],
+	astral: ["Occultism"],
+	beast: ["Arcana", "Nature"],
+	celestial: ["Religion"],
+	construct: ["Arcana", "Crafting"],
+	dragon: ["Arcana"],
+	dream: ["Occultism"],
+	elemental: ["Arcana", "Nature"],
+	ethereal: ["Occultism"],
+	fey: ["Nature"],
+	fiend: ["Religion"],
+	fungus: ["Nature"],
+	giant: ["Society"],
+	humanoid: ["Society"],
+	monitor: ["Religion"],
+	ooze: ["Occultism"],
+	plant: ["Nature"],
+	undead: ["Religion"],
+};
+
+export interface RecallKnowledge {
+	readonly dc: number;
+	readonly type: string;
+	readonly skills: readonly string[];
+}
+
+/**
+ * Calculate Recall Knowledge DC, type, and skill(s) for a PF2e creature.
+ *
+ * Returns `null` when no recognized type trait is found in the creature's
+ * traits array, indicating the Recall Knowledge line should be omitted.
+ */
+export function recallKnowledge(
+	level: number,
+	traits: readonly string[],
+): RecallKnowledge | null {
+	// Find the first type trait that maps to a skill
+	let matchedType: string | undefined;
+	let skills: readonly string[] | undefined;
+
+	for (const trait of traits) {
+		const lower = trait.toLowerCase();
+		const mapped = TYPE_TO_SKILLS[lower];
+		if (mapped) {
+			matchedType = trait;
+			skills = mapped;
+			break;
+		}
+	}
+
+	if (!matchedType || !skills) return null;
+
+	// Calculate DC from level
+	const clampedIndex = Math.max(0, Math.min(level + 1, DC_BY_LEVEL.length - 1));
+	let dc = DC_BY_LEVEL[clampedIndex];
+
+	// Apply rarity adjustment (rarity traits are included in the traits array
+	// for non-common creatures by the normalization pipeline)
+	for (const trait of traits) {
+		const adjustment = RARITY_ADJUSTMENT[trait.toLowerCase()];
+		if (adjustment) {
+			dc += adjustment;
+			break;
+		}
+	}
+
+	return { dc, type: matchedType, skills };
+}

specs/004-bestiary/spec.md

@@ -103,6 +103,11 @@ As a DM running a PF2e encounter, I want to click a spell name in a creature's s
 
 A click on any spell name in the spellcasting section opens a popover (desktop) or bottom sheet (mobile) showing the spell's description, level, traits, range, action cost, target/area, duration, defense/save, and heightening rules. The data is read directly from the cached creature data (already embedded in NPC JSON from Foundry VTT) — no additional network fetch is required, and the feature works offline once the source has been loaded. Dismiss with click-outside, Escape, or (on mobile) swipe-down.
 
+**US-D5 — View Recall Knowledge DC and Skill (P2)**
+As a DM running a PF2e encounter, I want to see the Recall Knowledge DC and associated skill on a creature's stat block so I can quickly tell players the DC and which skill to roll without looking it up in external tools.
+
+The Recall Knowledge line appears below the trait tags, showing the DC (calculated from the creature's level using the PF2e standard DC-by-level table, adjusted for rarity) and the skill determined by the creature's type trait. The line is omitted for creatures with no recognized type trait and never shown for D&D creatures.
+
 ### Requirements
 
 - **FR-016**: The system MUST display a stat block panel with full creature information when a creature is selected.
@@ -148,6 +153,10 @@ A click on any spell name in the spellcasting section opens a popover (desktop)
 15. **Given** the spell description bottom sheet is open on mobile, **When** the DM swipes the sheet down, **Then** the sheet dismisses.
 16. **Given** a creature from a legacy (non-remastered) PF2e source has spells with pre-remaster names (e.g., "Magic Missile", "True Strike"), **When** the DM clicks one of those spell names, **Then** the spell description still displays correctly using the embedded data.
 17. **Given** a spell name appears as "Heal (×3)" in the stat block, **When** the DM looks at the rendered output, **Then** "Heal" is the clickable element and "(×3)" appears as plain text next to it.
+18. **Given** a PF2e creature with level 5 and common rarity is displayed, **When** the DM views the stat block, **Then** a "Recall Knowledge" line appears below the trait tags showing the DC calculated from level 5 (DC 20) and the skill derived from the creature's type trait.
+19. **Given** a PF2e creature with rare rarity is displayed, **When** the DM views the stat block, **Then** the Recall Knowledge DC is the standard DC for its level +5.
+20. **Given** a PF2e creature with the "Undead" type trait is displayed, **When** the DM views the stat block, **Then** the Recall Knowledge line shows "Religion" as the associated skill.
+21. **Given** a D&D creature is displayed, **When** the DM views the stat block, **Then** no Recall Knowledge line is shown.
 
 ### Edge Cases
 
@@ -156,6 +165,8 @@ A click on any spell name in the spellcasting section opens a popover (desktop)
 - Viewport resized from wide to narrow while stat block is open: the layout transitions from panel to drawer.
 - Embedded spell item missing description text: the popover/sheet shows the available metadata (level, traits, range, etc.) and a placeholder note for the missing description.
 - Cached source data from before the spell description feature was added: existing cached entries lack the new per-spell data fields. The IndexedDB schema version MUST be bumped to invalidate old caches and trigger re-fetch (re-normalization from raw Foundry data is not possible because the original raw JSON is not retained).
+- Creature with no recognized type trait (e.g., a creature whose only traits are not in the type-to-skill mapping): the Recall Knowledge line is omitted entirely.
+- Creature with a type trait that maps to multiple skills (e.g., Beast → Arcana/Nature): both skills are shown.
 
 ---
 
@@ -217,6 +228,11 @@ A DM wants to see which sources are cached, find a specific source, clear a spec
 - **FR-075**: PF2e creature abilities MUST have complete descriptive text in stat blocks. Stubs, generic feat references, and unresolved copy entries are not acceptable.
 - **FR-076**: The PF2e index SHOULD carry per-creature license tagging (ORC/OGL) derived from the Foundry VTT source data.
 - **FR-084**: The PF2e normalization pipeline MUST preserve per-spell data (slug, level, traits, range, time, target, area, duration, defense, description, heightening/overlays) from embedded `items[type=spell]` entries on NPCs, in addition to the spell name. This data MUST be stored in the cached source data and persisted across browser sessions.
+- **FR-085**: PF2e stat blocks MUST display a "Recall Knowledge" line below the trait tags showing the DC and the associated skill (e.g., "Recall Knowledge DC 18 • Undead (Religion)").
+- **FR-086**: The Recall Knowledge DC MUST be calculated from the creature's level using the PF2e standard DC-by-level table, adjusted for rarity: uncommon +2, rare +5, unique +10.
+- **FR-087**: The Recall Knowledge skill MUST be derived from the creature's type trait using the standard PF2e mapping (e.g., Aberration → Occultism, Animal → Nature, Astral → Occultism, Beast → Arcana/Nature, Celestial → Religion, Construct → Arcana/Crafting, Dragon → Arcana, Dream → Occultism, Elemental → Arcana/Nature, Ethereal → Occultism, Fey → Nature, Fiend → Religion, Fungus → Nature, Giant → Society, Humanoid → Society, Monitor → Religion, Ooze → Occultism, Plant → Nature, Undead → Religion).
+- **FR-088**: Creatures with no recognized type trait MUST omit the Recall Knowledge line entirely rather than showing incorrect data.
+- **FR-089**: The Recall Knowledge line MUST NOT be shown for D&D creatures.
 
 ### Acceptance Scenarios