diff --git a/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_actions.ts b/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_actions.ts
index d42388f8..f54c6707 100644
--- a/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_actions.ts
+++ b/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_actions.ts
@@ -125,11 +125,15 @@ const callbacksⵧto_actions: Partial<WalkerCallbacks<State, RenderingOptionsⵧ
 	on_type,
 }
 
-function renderⵧto_actions($doc: NodeLike, options: RenderingOptionsⵧToActions = DEFAULT_RENDERING_OPTIONSⵧToActions): Action[] {
+function renderⵧto_actions($doc: NodeLike, options: Partial<RenderingOptionsⵧToActions> = {}): Action[] {
 	if (typeof $doc !== 'object') {
 		return []
 	}
-	return walk<State, RenderingOptionsⵧToActions>($doc, callbacksⵧto_actions, options).actions
+	const full_options: RenderingOptionsⵧToActions = {
+		...DEFAULT_RENDERING_OPTIONSⵧToActions,
+		...options,
+	}
+	return walk<State, RenderingOptionsⵧToActions>($doc, callbacksⵧto_actions, full_options).actions
 }
 
 /////////////////////////////////////////////////
diff --git a/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_debug.ts b/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_debug.ts
index 328c93a5..38c6047e 100644
--- a/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_debug.ts
+++ b/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_debug.ts
@@ -38,8 +38,8 @@ function debug_node_short($node: CheckedNode) {
 
 ////////////////////////////////////
 
-interface RenderingOptions extends BaseRenderingOptions {}
-const DEFAULT_RENDERING_OPTIONS= Object.freeze<RenderingOptions>({
+interface RenderingOptionsⵧToDebug extends BaseRenderingOptions {}
+const DEFAULT_RENDERING_OPTIONSⵧToDebug= Object.freeze<RenderingOptionsⵧToDebug>({
 	...DEFAULT_RENDERING_OPTIONSⵧWalk,
 })
 
@@ -65,7 +65,7 @@ const on_nodeⵧenter = ({$node, $id, depth}: OnNodeEnterParams): State => {
 	return state
 }
 
-const on_nodeⵧexit: WalkerReducer<State, OnNodeExitParams<State>, RenderingOptions> = ({$node, $id, state, depth}) => {
+const on_nodeⵧexit: WalkerReducer<State, OnNodeExitParams<State>, RenderingOptionsⵧToDebug> = ({$node, $id, state, depth}) => {
 	console.log(indent(depth) + `⟨ [on_nodeⵧexit] #${$id}`)
 	console.log(indent(depth) + `  [state="${state}"]`)
 	consoleGroupEnd()
@@ -75,42 +75,42 @@ const on_nodeⵧexit: WalkerReducer<State, OnNodeExitParams<State>, RenderingOpt
 
 
 // when walking inside the content
-const on_concatenateⵧstr: WalkerReducer<State, OnConcatenateStringParams<State>, RenderingOptions> = ({str, state, $node, depth}) => {
+const on_concatenateⵧstr: WalkerReducer<State, OnConcatenateStringParams<State>, RenderingOptionsⵧToDebug> = ({str, state, $node, depth}) => {
 	console.log(indent(depth) + `+ [on_concatenateⵧstr] "${str}"`)
 	state = state + str
 	console.log(indent(depth) + `  [state="${state}"]`)
 	return state
 }
 
-const on_concatenateⵧsub_node: WalkerReducer<State, OnConcatenateSubNodeParams<State>, RenderingOptions> = ({state, sub_state, depth, $id, $parent_node}) => {
+const on_concatenateⵧsub_node: WalkerReducer<State, OnConcatenateSubNodeParams<State>, RenderingOptionsⵧToDebug> = ({state, sub_state, depth, $id, $parent_node}) => {
 	console.log(indent(depth) + `+ [on_concatenateⵧsub_node] "${sub_state}"`)
 	state = state + sub_state
 	console.log(indent(depth) + `  [state="${state}"]`)
 	return state
 }
 
-const on_filter: WalkerReducer<State, OnFilterParams<State>, RenderingOptions> = ({$filter, $filters, state, $node, depth}) => {
+const on_filter: WalkerReducer<State, OnFilterParams<State>, RenderingOptionsⵧToDebug> = ({$filter, $filters, state, $node, depth}) => {
 	console.log(indent(depth) + `  [on_filter] "${$filter}`)
 	return state
 }
 
-const on_classⵧbefore: WalkerReducer<State, OnClassParams<State>, RenderingOptions> = ({$class, state, $node, depth}) => {
+const on_classⵧbefore: WalkerReducer<State, OnClassParams<State>, RenderingOptionsⵧToDebug> = ({$class, state, $node, depth}) => {
 	console.log(indent(depth) + `  [⟩on_classⵧbefore] .${$class}`)
 	return state
 }
-const on_classⵧafter: WalkerReducer<State, OnClassParams<State>, RenderingOptions> = ({$class, state, $node, depth}) => {
+const on_classⵧafter: WalkerReducer<State, OnClassParams<State>, RenderingOptionsⵧToDebug> = ({$class, state, $node, depth}) => {
 	console.log(indent(depth) + `  [⟨on_classⵧafter] .${$class}`)
 	return state
 }
 
-const on_type: WalkerReducer<State, OnTypeParams<State>, RenderingOptions> = ({$type, state, $node, depth}) => {
+const on_type: WalkerReducer<State, OnTypeParams<State>, RenderingOptionsⵧToDebug> = ({$type, state, $node, depth}) => {
 	console.log(indent(depth) + `  [on_type] "${$type}" ${$node.$classes}`)
 	return state
 }
 
 ////////////////////////////////////
 
-const callbacksⵧto_debug: Partial<WalkerCallbacks<State, RenderingOptions>> = {
+const callbacksⵧto_debug: Partial<WalkerCallbacks<State, RenderingOptionsⵧToDebug>> = {
 	on_rootⵧenter,
 	on_rootⵧexit,
 
@@ -142,13 +142,18 @@ const callbacksⵧto_debug: Partial<WalkerCallbacks<State, RenderingOptions>> =
 	},
 }
 
-function renderⵧto_debug($doc: Node, options: RenderingOptions = DEFAULT_RENDERING_OPTIONS): string {
-	return walk<State, RenderingOptions>($doc, callbacksⵧto_debug, options)
+function renderⵧto_debug($doc: Node, options: Partial<RenderingOptionsⵧToDebug> = {}): string {
+	const full_options: RenderingOptionsⵧToDebug = {
+		...DEFAULT_RENDERING_OPTIONSⵧToDebug,
+		...options,
+	}
+	return walk<State, RenderingOptionsⵧToDebug>($doc, callbacksⵧto_debug, full_options)
 }
 
 /////////////////////////////////////////////////
 
 export {
+	DEFAULT_RENDERING_OPTIONSⵧToDebug,
 	callbacksⵧto_debug,
 	renderⵧto_debug,
 }
diff --git a/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_html.ts b/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_html.ts
index 89c9955b..90b4d095 100644
--- a/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_html.ts
+++ b/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_html.ts
@@ -144,10 +144,18 @@ const callbacksⵧto_html: Partial<WalkerCallbacks<State, RenderingOptionsⵧToH
 	on_nodeⵧexit,
 }
 
-function renderⵧto_html($doc: Node, options: RenderingOptionsⵧToHtml = DEFAULT_RENDERING_OPTIONSⵧToHtml): string {
-	return '<div class="o⋄rich-text o⋄children-spacing⁚flow">\n	'
-		+ walk<State, RenderingOptionsⵧToHtml>($doc, callbacksⵧto_html, options).str
-		+ '\n</div>\n'
+function renderⵧto_html($doc: Node, options: Partial<RenderingOptionsⵧToHtml> = {}): string {
+	const full_options: RenderingOptionsⵧToHtml = {
+		...DEFAULT_RENDERING_OPTIONSⵧToHtml,
+		...options,
+	}
+
+	// TODO review classes
+	return `
+<div class="o⋄rich-text o⋄children-spacing⁚flow">
+	${walk<State, RenderingOptionsⵧToHtml>($doc, callbacksⵧto_html, full_options).str}
+</div>
+`
 }
 
 /////////////////////////////////////////////////
diff --git a/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_text.ts b/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_text.ts
index 7e81b11d..65fdfdcd 100644
--- a/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_text.ts
+++ b/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_text.ts
@@ -241,13 +241,17 @@ const callbacksⵧto_text: Partial<WalkerCallbacks<State, RenderingOptionsⵧToT
 
 function renderⵧto_text(
 	$doc: Node,
-	options: RenderingOptionsⵧToText = DEFAULT_RENDERING_OPTIONSⵧToText,
+	options: Partial<RenderingOptionsⵧToText> = {},
 	callback_overrides: Partial<WalkerCallbacks<State, RenderingOptionsⵧToText>> = {},
 ): string {
+	const full_options: RenderingOptionsⵧToText = {
+		...DEFAULT_RENDERING_OPTIONSⵧToText,
+		...options,
+	}
 	return walk<State, RenderingOptionsⵧToText>($doc, {
 		...callbacksⵧto_text,
 		...callback_overrides,
-	}, options).str
+	}, full_options).str
 }
 
 /////////////////////////////////////////////////
diff --git a/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_text_spec.ts b/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_text_spec.ts
index 240dd2e0..d357bbd1 100644
--- a/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_text_spec.ts
+++ b/stack--current/3-advanced--multi/rich-text-format/src/renderers/to_text_spec.ts
@@ -7,11 +7,9 @@ import * as RichText from '../index.js'
 /////////////////////////////////////////////////
 
 describe(`${LIB} -- renderers -- to text`, () => {
-	let rendering_options = RichText.DEFAULT_RENDERING_OPTIONSⵧToText
+	let rendering_options = {}
 	beforeEach(() => {
-		rendering_options = {
-			...RichText.DEFAULT_RENDERING_OPTIONSⵧToText,
-		}
+		rendering_options = {}
 	})
 
 	const $DEMOⵧSIMPLE = (() => {
diff --git a/stack--current/3-advanced--multi/rich-text-format/src/renderers/walk.ts b/stack--current/3-advanced--multi/rich-text-format/src/renderers/walk.ts
index 9612e55d..e8ed8c4c 100644
--- a/stack--current/3-advanced--multi/rich-text-format/src/renderers/walk.ts
+++ b/stack--current/3-advanced--multi/rich-text-format/src/renderers/walk.ts
@@ -10,7 +10,6 @@ import {
 
 import { normalizeꓽnode } from '../utils/normalize.js'
 import { promoteꓽto_node } from '../utils/promote.js'
-import { Action, EmbeddedReducerAction, HyperlinkAction, ReducerAction, RenderingOptionsⵧToActions } from './to_actions'
 
 /////////////////////////////////////////////////
 // "walk" is the foundation on which all the renderer are based
@@ -268,8 +267,11 @@ function _walk_content<State, RenderingOptions extends BaseRenderingOptions>(
 				return { $content: `{{??${sub_node_id}??}}` }
 			}
 
-			//console.error($node, { $content, sub_node_id })
-			throw new Error(`${LIB}: syntax error in content "${$content}", it's referencing an unknown sub-node "${sub_node_id}"!`)
+			if (true) {
+				console.error('shouldꓽrecover_from_unknown_sub_nodes FAILURE',)
+				console.error($node, { $content, sub_node_id })
+			}
+			throw new Error(`${LIB}: syntax error in content "${$content}", it's referencing an unknown sub-node "${sub_node_id}"! (recover mode = ${options.shouldꓽrecover_from_unknown_sub_nodes})`)
 		})())
 
 		let sub_state = _walk($sub_node, callbacks, options, {
@@ -437,17 +439,26 @@ function _walk<State, RenderingOptions extends BaseRenderingOptions>(
 function walk<State, RenderingOptions extends BaseRenderingOptions>(
 	$raw_node: Readonly<Node>,
 	raw_callbacks: Readonly<Partial<WalkerCallbacks<State, RenderingOptions>>>,
-	options: Readonly<RenderingOptions> = {} as any,
+	options: RenderingOptions, // this internal fn can't default unknown type, so we expect the caller to give us full options
 ) {
-	if (!Object.keys(raw_callbacks).every(k => k === 'resolve_unknown_subnode' || k.startsWith('on_')))
-		console.warn(`${LIB} Unexpected unrecognized callbacks, check the API!`)
+	assert(
+		Object.keys(raw_callbacks).every(k => k === 'resolve_unknown_subnode' || k.startsWith('on_')),
+		`${LIB}[walk]: custom callbacks should match the expected format, check the API!`
+	)
 
 	const callbacks: WalkerCallbacks<State, RenderingOptions> = {
 		..._getꓽcallbacksⵧdefault<State, RenderingOptions>(),
 		...raw_callbacks as any as WalkerCallbacks<State, RenderingOptions>,
 	}
 
+	assert(
+		// detect incorrectly built options (actual issue before rewrite in 2024)
+		options.shouldꓽrecover_from_unknown_sub_nodes !== undefined,
+		`${LIB}[walk]: options should be a fully initialized options object!`
+	)
+
 	const $root_node = normalizeꓽnode($raw_node)
+
 	return _walk($root_node, callbacks, options, {
 		$parent_node: null,
 		$id: 'root',
diff --git a/stack--current/3-advanced--multi/rich-text-format/src/renderers/walk_spec.ts b/stack--current/3-advanced--multi/rich-text-format/src/renderers/walk_spec.ts
index ade78213..352e4964 100644
--- a/stack--current/3-advanced--multi/rich-text-format/src/renderers/walk_spec.ts
+++ b/stack--current/3-advanced--multi/rich-text-format/src/renderers/walk_spec.ts
@@ -5,17 +5,31 @@ import { LIB } from '../consts.js'
 /////////////////////////////////////////////////
 
 import * as RichText from '../index.js'
-import { walk, WalkerCallbacks } from './walk.js'
-import { BaseRenderingOptions, Node } from '../index.js'
+import {
+	walk,
+	type WalkerCallbacks,
+} from './walk.js'
+import {
+	type BaseRenderingOptions,
+	type Node,
+} from '../index.js'
 
 describe(`${LIB} -- renderers -- walker (internal)`, function () {
-
 	interface State {}
 	interface Options extends BaseRenderingOptions {}
 	const callbacks: Partial<WalkerCallbacks<State, Options>> = {
 		on_nodeⵧenter() { return {} as State },
 	}
 
+	let rendering_options: Options = {
+		shouldꓽrecover_from_unknown_sub_nodes: false,
+	}
+	beforeEach(() => {
+		rendering_options = {
+			shouldꓽrecover_from_unknown_sub_nodes: false,
+		}
+	})
+
 	describe('walking through all nodes in order', function () {
 
 		it('should work')
@@ -76,7 +90,7 @@ describe(`${LIB} -- renderers -- walker (internal)`, function () {
 				},
 			}
 
-			expect(() => walk<State, Options>($doc, {...callbacks})).to.throw('unknown sub-node')
+			expect(() => walk<State, Options>($doc, {...callbacks}, rendering_options)).to.throw('unknown sub-node')
 		})
 
 		it('should work -- handling missing -- auto recovery -- placeholder', () => {
@@ -160,7 +174,7 @@ describe(`${LIB} -- renderers -- walker (internal)`, function () {
 			const $doc = {
 				$content: '⎨⎨foo',
 			}
-			expect(() => walk<State, Options>($doc, {...callbacks})).to.throw('unmatched')
+			expect(() => walk<State, Options>($doc, {...callbacks}, rendering_options)).to.throw('unmatched')
 		})
 		it('should detect unmatched ⎨⎨⎬⎬ -- ⎨⎨ 2', () => {
 			const $doc = {
@@ -169,7 +183,7 @@ describe(`${LIB} -- renderers -- walker (internal)`, function () {
 					'foo': {}
 				},
 			}
-			expect(() => walk<State, Options>($doc, {...callbacks})).to.throw('unmatched')
+			expect(() => walk<State, Options>($doc, {...callbacks}, rendering_options)).to.throw('unmatched')
 		})
 
 		it('should detect unmatched ⎨⎨⎬⎬ -- ⎬⎬ 1', () => {
@@ -177,7 +191,7 @@ describe(`${LIB} -- renderers -- walker (internal)`, function () {
 			const $doc = {
 				$content: 'foo⎬⎬',
 			}
-			expect(() => walk<State, Options>($doc, {...callbacks})).to.throw('unmatched')
+			expect(() => walk<State, Options>($doc, {...callbacks}, rendering_options)).to.throw('unmatched')
 		})
 		it('should detect unmatched ⎨⎨⎬⎬ -- ⎬⎬ 2a', () => {
 
@@ -187,7 +201,7 @@ describe(`${LIB} -- renderers -- walker (internal)`, function () {
 					'foo': {}
 				},
 			}
-			expect(() => walk<State, Options>($doc, {...callbacks})).to.throw('unmatched')
+			expect(() => walk<State, Options>($doc, {...callbacks}, rendering_options)).to.throw('unmatched')
 		})
 		it('should detect unmatched ⎨⎨⎬⎬ -- ⎬⎬ 2b', () => {
 
@@ -197,7 +211,7 @@ describe(`${LIB} -- renderers -- walker (internal)`, function () {
 					'foo': {}
 				},
 			}
-			expect(() => walk<State, Options>($doc, {...callbacks})).to.throw('unmatched')
+			expect(() => walk<State, Options>($doc, {...callbacks}, rendering_options)).to.throw('unmatched')
 		})
 
 		it('should detect reversed ⎨⎨⎬⎬', () => {
@@ -208,7 +222,7 @@ describe(`${LIB} -- renderers -- walker (internal)`, function () {
 					'foo': {}
 				},
 			}
-			expect(() => walk<State, Options>($doc, {...callbacks})).to.throw('unmatched')
+			expect(() => walk<State, Options>($doc, {...callbacks}, rendering_options)).to.throw('unmatched')
 		})
 	})
 })
diff --git a/stack--current/3-advanced--multi/rich-text-format/src/sugar/builder.ts b/stack--current/3-advanced--multi/rich-text-format/src/sugar/builder.ts
index 0e728dea..6859ddfe 100644
--- a/stack--current/3-advanced--multi/rich-text-format/src/sugar/builder.ts
+++ b/stack--current/3-advanced--multi/rich-text-format/src/sugar/builder.ts
@@ -27,12 +27,12 @@ interface Builder {
 	// node ref is auto added into content
 	pushNode(node: Node, options?: CommonOptions): Builder
 
-	// nothing is added in content
+	// NOTHING is added into content
 	// useful for
 	// 1. lists
 	// 2. manual stuff
-	pushRawNode(node: Node, options?: CommonOptions): Builder
-	pushRawNodes(nodes: { [id: string]: Node }): Builder // batch version
+	pushRawNode(node: CheckedNode['$sub'][string], options?: CommonOptions): Builder
+	pushRawNodes(nodes: CheckedNode['$sub']): Builder // batch version
 
 	pushInlineFragment(str: string, options?: CommonOptions): Builder
 	pushBlockFragment(str: string, options?: CommonOptions): Builder
diff --git a/stack--current/A-apps--core/the-boring-rpg/l2-state/src/reducers/achievements/index.ts b/stack--current/A-apps--core/the-boring-rpg/l2-state/src/reducers/achievements/index.ts
index 714c62bb..3f9d632c 100644
--- a/stack--current/A-apps--core/the-boring-rpg/l2-state/src/reducers/achievements/index.ts
+++ b/stack--current/A-apps--core/the-boring-rpg/l2-state/src/reducers/achievements/index.ts
@@ -39,8 +39,10 @@ function _refresh_achievements(state: Immutable<State>): Immutable<State> {
 			engagement = enqueueEngagement(engagement,
 					getꓽengagement_template(EngagementTemplateKey.achievement_unlocked),
 					{
-						icon,
-						name,
+						$sub: {
+							icon,
+							name,
+						},
 					},
 				)
 		}
diff --git a/stack--current/A-apps--core/the-boring-rpg/x-sandbox/src/to-export-to-own-package/hateoas/utils.ts b/stack--current/A-apps--core/the-boring-rpg/x-sandbox/src/to-export-to-own-package/hateoas/utils.ts
index c331bd16..1b8ef0b0 100644
--- a/stack--current/A-apps--core/the-boring-rpg/x-sandbox/src/to-export-to-own-package/hateoas/utils.ts
+++ b/stack--current/A-apps--core/the-boring-rpg/x-sandbox/src/to-export-to-own-package/hateoas/utils.ts
@@ -1,10 +1,12 @@
 import assert from 'tiny-invariant'
 import { type Immutable } from '@offirmo-private/ts-types'
 
+import { getꓽmutable_copy } from '@offirmo-private/state-utils'
 import {
 	type NodeLike,
 	type Node,
-	promoteꓽto_nodeⵧimmutable,
+	type CheckedNode,
+	createⵧfrom_content,
 } from '@offirmo-private/rich-text-format'
 import {
 	type PendingEngagement,
@@ -15,14 +17,47 @@ import { type HATEOASPendingEngagement } from './types.js'
 
 /////////////////////////////////////////////////
 
+const EXPECTED_FIELDS = new Set(['$sub', '$hints'])
+function assertꓽparams__shape(params: PendingEngagement<NodeLike>['params']): Pick<CheckedNode, '$sub' | '$hints'> {
+	const result: Pick<CheckedNode, '$sub' | '$hints'> = {
+		$sub: {},
+		$hints: {},
+	}
+
+	const keys = Object.keys(params)
+	keys.forEach(k => {
+		assert(EXPECTED_FIELDS.has(k), `a HATEOAS RichText PendingEngagement params should not contain extraneous fields! ("${k}")`)
+	})
+
+	result.$sub = {
+		...params?.['$sub'],
+	}
+	result.$hints = {
+		...params?.['$hints'],
+	}
+
+	return result
+}
+
 function resolveꓽrich_text_pending_engagement<Action>(
 	pe: Immutable<PendingEngagement<NodeLike>>,
 	uid_to_ack: (uid: PendingEngagementUId) => Immutable<Action>,
 ): Immutable<HATEOASPendingEngagement<Node, Action>> {
-	const $doc = promoteꓽto_nodeⵧimmutable(pe.template.content)
+	const template__contentⵧmutable = getꓽmutable_copy(pe.template.content)
+
+	const builder = createⵧfrom_content(template__contentⵧmutable)
+	const extras = assertꓽparams__shape(pe.params)
+	builder.pushRawNodes(extras.$sub)
+	builder.addHints(extras.$hints)
+
+	/*console.warn(`XXX`, {
+		raw_params: pe.params,
+		extras,
+		content: builder.done(),
+	})*/
 
 	return {
-		content: $doc,
+		content: builder.done(),
 		flow: pe.template.flow,
 		role: pe.template.role,
 		...(pe.template.success !== undefined && { success: pe.template.success }),