From e20cd87ef9a71b02a9070ecf3850ac6031fe3b9c Mon Sep 17 00:00:00 2001
From: hugocasa <hugo@casademont.ch>
Date: Thu, 17 Sep 2026 14:42:08 +0200
Subject: [PATCH] feat: edit a nested AI agent's own tools from the flow editor

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 .../components/flows/agentToolTree.test.ts    | 20 +++++++---
 .../src/lib/components/flows/agentToolTree.ts | 26 +++++++------
 .../components/flows/common/FlowCard.svelte   |  4 ++
 .../flows/common/FlowCardHeader.svelte        |  4 ++
 .../flows/content/AgentToolRoster.svelte      |  6 ++-
 .../flows/content/AgentToolWrapper.svelte     |  9 ++++-
 .../flows/content/AiAgentStepInputs.svelte    |  1 +
 .../flows/content/FlowModuleComponent.svelte  | 31 +++++++++++++++-
 .../flows/content/FlowModuleWrapper.svelte    | 37 ++++++++++++-------
 .../flows/map/FlowModuleSchemaMap.svelte      | 12 +++++-
 .../flows/map/InsertModuleInner.svelte        | 20 ++++++----
 11 files changed, 129 insertions(+), 41 deletions(-)

diff --git a/frontend/src/lib/components/flows/agentToolTree.test.ts b/frontend/src/lib/components/flows/agentToolTree.test.ts
index 3e5b49e3a6..70da082068 100644
--- a/frontend/src/lib/components/flows/agentToolTree.test.ts
+++ b/frontend/src/lib/components/flows/agentToolTree.test.ts
@@ -59,20 +59,26 @@ describe('findAgentToolOwner', () => {
 	})
 
 	it('finds a nested tool owner inside a nested ai agent tool', () => {
-		const nestedAgent = makeAiAgent('support_agent', [makeFlowModuleTool(makeRawModule('create_ticket'))])
+		const nestedAgent = makeAiAgent('support_agent', [
+			makeFlowModuleTool(makeRawModule('create_ticket'))
+		])
 		const rootAgent = makeAiAgent('root_agent', [makeFlowModuleTool(nestedAgent)])
 
-		expect(findAgentToolOwner([rootAgent], 'create_ticket')).toMatchObject({
+		const owner = findAgentToolOwner([rootAgent], 'create_ticket')
+		expect(owner).toMatchObject({
 			agentId: 'support_agent',
 			toolIndex: 0,
 			depth: 2
 		})
+		expect(owner?.agents.map((agent) => agent.id)).toEqual(['root_agent', 'support_agent'])
 	})
 })
 
 describe('removeAgentToolOwner', () => {
 	it('removes the matched tool and returns its subtree ids', () => {
-		const nestedAgent = makeAiAgent('support_agent', [makeFlowModuleTool(makeRawModule('create_ticket'))])
+		const nestedAgent = makeAiAgent('support_agent', [
+			makeFlowModuleTool(makeRawModule('create_ticket'))
+		])
 		const rootAgent = makeAiAgent('root_agent', [
 			makeFlowModuleTool(makeRawModule('lookup_user')),
 			makeFlowModuleTool(nestedAgent)
@@ -85,7 +91,9 @@ describe('removeAgentToolOwner', () => {
 			removedIds: ['support_agent', 'create_ticket']
 		})
 		expect((rootAgent.value as any).tools).toHaveLength(1)
-		expect(((rootAgent.value as any).tools as any[]).map((tool) => tool.id)).toEqual(['lookup_user'])
+		expect(((rootAgent.value as any).tools as any[]).map((tool) => tool.id)).toEqual([
+			'lookup_user'
+		])
 	})
 })
 
@@ -93,7 +101,9 @@ describe('collectFlowNodeIds', () => {
 	it('includes ai agent tool ids when deleting an ai agent flow module', () => {
 		const agent = makeAiAgent('root_agent', [
 			makeFlowModuleTool(makeRawModule('lookup_user')),
-			makeFlowModuleTool(makeAiAgent('support_agent', [makeFlowModuleTool(makeRawModule('create_ticket'))]))
+			makeFlowModuleTool(
+				makeAiAgent('support_agent', [makeFlowModuleTool(makeRawModule('create_ticket'))])
+			)
 		])
 
 		expect(collectFlowNodeIds(agent)).toEqual([
diff --git a/frontend/src/lib/components/flows/agentToolTree.ts b/frontend/src/lib/components/flows/agentToolTree.ts
index c30804c21d..5e01d5ef07 100644
--- a/frontend/src/lib/components/flows/agentToolTree.ts
+++ b/frontend/src/lib/components/flows/agentToolTree.ts
@@ -7,7 +7,7 @@ import {
 } from './agentToolUtils'
 import { forEachAiAgentModule } from './aiAgentModules'
 
-type FlowNodeLike = Pick<FlowModule, 'id' | 'value'>
+type FlowNodeLike = Pick<FlowModule, 'id' | 'value' | 'summary'>
 
 export type AgentToolOwner = {
 	agentId: string
@@ -15,6 +15,8 @@ export type AgentToolOwner = {
 	toolIndex: number
 	tool: AgentTool
 	depth: number
+	/** Every agent the tool sits under, the step's own first and `agentId`'s last. */
+	agents: FlowNodeLike[]
 }
 
 export type RemovedAgentTool = {
@@ -26,7 +28,7 @@ export function findAgentToolOwner(
 	modules: FlowModule[],
 	toolId: string
 ): AgentToolOwner | undefined {
-	return findAgentToolOwnerInModules(modules, toolId, 0)
+	return findAgentToolOwnerInModules(modules, toolId, [])
 }
 
 export function removeAgentToolOwner(owner: AgentToolOwner): RemovedAgentTool | undefined {
@@ -53,10 +55,10 @@ export function collectAgentToolIds(tool: AgentTool): string[] {
 function findAgentToolOwnerInModules(
 	modules: FlowModule[],
 	toolId: string,
-	depth: number
+	agents: FlowNodeLike[]
 ): AgentToolOwner | undefined {
 	for (const module of modules) {
-		const owner = findAgentToolOwnerInNode(module, toolId, depth)
+		const owner = findAgentToolOwnerInNode(module, toolId, agents)
 		if (owner) {
 			return owner
 		}
@@ -68,15 +70,15 @@ function findAgentToolOwnerInModules(
 function findAgentToolOwnerInNode(
 	node: FlowNodeLike,
 	toolId: string,
-	depth: number
+	agents: FlowNodeLike[]
 ): AgentToolOwner | undefined {
 	if (node.value.type === 'forloopflow' || node.value.type === 'whileloopflow') {
-		return findAgentToolOwnerInModules(node.value.modules, toolId, depth)
+		return findAgentToolOwnerInModules(node.value.modules, toolId, agents)
 	}
 
 	if (node.value.type === 'branchall') {
 		for (const branch of node.value.branches) {
-			const owner = findAgentToolOwnerInModules(branch.modules, toolId, depth)
+			const owner = findAgentToolOwnerInModules(branch.modules, toolId, agents)
 			if (owner) {
 				return owner
 			}
@@ -85,12 +87,12 @@ function findAgentToolOwnerInNode(
 	}
 
 	if (node.value.type === 'branchone') {
-		const defaultOwner = findAgentToolOwnerInModules(node.value.default, toolId, depth)
+		const defaultOwner = findAgentToolOwnerInModules(node.value.default, toolId, agents)
 		if (defaultOwner) {
 			return defaultOwner
 		}
 		for (const branch of node.value.branches) {
-			const owner = findAgentToolOwnerInModules(branch.modules, toolId, depth)
+			const owner = findAgentToolOwnerInModules(branch.modules, toolId, agents)
 			if (owner) {
 				return owner
 			}
@@ -102,6 +104,7 @@ function findAgentToolOwnerInNode(
 		return undefined
 	}
 
+	const withNode = [...agents, node]
 	// Absent for a linked agent, whose tools live in the resource rather than on the module.
 	const tools = node.value.tools ?? []
 	const toolIndex = tools.findIndex((tool) => tool.id === toolId)
@@ -111,7 +114,8 @@ function findAgentToolOwnerInNode(
 			tools,
 			toolIndex,
 			tool: tools[toolIndex],
-			depth: depth + 1
+			depth: withNode.length,
+			agents: withNode
 		}
 	}
 
@@ -120,7 +124,7 @@ function findAgentToolOwnerInNode(
 			continue
 		}
 
-		const owner = findAgentToolOwnerInNode(tool as FlowNodeLike, toolId, depth + 1)
+		const owner = findAgentToolOwnerInNode(tool as FlowNodeLike, toolId, withNode)
 		if (owner) {
 			return owner
 		}
diff --git a/frontend/src/lib/components/flows/common/FlowCard.svelte b/frontend/src/lib/components/flows/common/FlowCard.svelte
index 091d3a9feb..86c8ae7158 100644
--- a/frontend/src/lib/components/flows/common/FlowCard.svelte
+++ b/frontend/src/lib/components/flows/common/FlowCard.svelte
@@ -14,6 +14,8 @@
 		header?: import('svelte').Snippet
 		action?: import('svelte').Snippet
 		children?: import('svelte').Snippet
+		/** See `FlowCardHeader`. */
+		trail?: import('svelte').Snippet
 		isAgentTool?: boolean
 		siblingToolNames?: string[]
 	}
@@ -30,6 +32,7 @@
 		header,
 		action,
 		children,
+		trail,
 		isAgentTool = false,
 		siblingToolNames = undefined
 	}: Props = $props()
@@ -49,6 +52,7 @@
 				{subtitleDocLink}
 				{flowModuleValue}
 				{action}
+				{trail}
 				{isAgentTool}
 				{siblingToolNames}
 			>
diff --git a/frontend/src/lib/components/flows/common/FlowCardHeader.svelte b/frontend/src/lib/components/flows/common/FlowCardHeader.svelte
index 063367cc85..1c373135e4 100644
--- a/frontend/src/lib/components/flows/common/FlowCardHeader.svelte
+++ b/frontend/src/lib/components/flows/common/FlowCardHeader.svelte
@@ -39,6 +39,8 @@
 		subtitleDocLink?: string | undefined
 		children?: import('svelte').Snippet
 		action?: import('svelte').Snippet
+		/** A line above the header naming where the step sits. */
+		trail?: import('svelte').Snippet
 		isAgentTool?: boolean
 		siblingToolNames?: string[]
 	}
@@ -52,6 +54,7 @@
 		subtitleDocLink = undefined,
 		children,
 		action,
+		trail,
 		isAgentTool = false,
 		siblingToolNames = undefined
 	}: Props = $props()
@@ -192,6 +195,7 @@
 </script>
 
 <div class="flex flex-col gap-1 px-4 py-2">
+	{@render trail?.()}
 	<div
 		class="overflow-x-auto scrollbar-hidden flex items-center justify-between flex-nowrap w-full"
 	>
diff --git a/frontend/src/lib/components/flows/content/AgentToolRoster.svelte b/frontend/src/lib/components/flows/content/AgentToolRoster.svelte
index 33abff2ba8..78d048270c 100644
--- a/frontend/src/lib/components/flows/content/AgentToolRoster.svelte
+++ b/frontend/src/lib/components/flows/content/AgentToolRoster.svelte
@@ -20,6 +20,8 @@
 		emptyMessage?: string
 		/** Where the picker's popover belongs, when the roster is not inside the flow editor. */
 		pickerPortal?: string
+		/** See `InsertModuleInner`. */
+		allowAiAgentTool?: boolean
 	}
 
 	let {
@@ -28,7 +30,8 @@
 		onAddTool = undefined,
 		onDeleteTool = undefined,
 		emptyMessage = 'No tools yet. Add one from the agent on the flow graph.',
-		pickerPortal = '#flow-editor'
+		pickerPortal = '#flow-editor',
+		allowAiAgentTool = true
 	}: Props = $props()
 
 	let funcDesc = $state('')
@@ -81,6 +84,7 @@
 			<InsertModuleInner
 				bind:funcDesc
 				toolMode
+				{allowAiAgentTool}
 				on:close={close}
 				on:new={(e) => (onAddTool?.(e.detail), close())}
 				on:insert={(e) => (onAddTool?.(e.detail), close())}
diff --git a/frontend/src/lib/components/flows/content/AgentToolWrapper.svelte b/frontend/src/lib/components/flows/content/AgentToolWrapper.svelte
index 6ccadc2ee5..304d07d857 100644
--- a/frontend/src/lib/components/flows/content/AgentToolWrapper.svelte
+++ b/frontend/src/lib/components/flows/content/AgentToolWrapper.svelte
@@ -20,6 +20,9 @@
 		staticOnly?: boolean
 		/** See `FlowModuleComponent`: set where there is no graph to select a nested tool on. */
 		noToolNavigation?: boolean
+		/** See `FlowModuleComponent`. */
+		agentTrail?: Pick<FlowModule, 'id' | 'summary'>[]
+		flowModuleSchemaMap?: import('../map/FlowModuleSchemaMap.svelte').default
 	}
 
 	let {
@@ -32,7 +35,9 @@
 		highlightArg,
 		siblingToolNames = undefined,
 		staticOnly = false,
-		noToolNavigation = false
+		noToolNavigation = false,
+		agentTrail = undefined,
+		flowModuleSchemaMap = undefined
 	}: Props = $props()
 </script>
 
@@ -65,6 +70,8 @@
 		isAgentTool={true}
 		{staticOnly}
 		{noToolNavigation}
+		{agentTrail}
+		{flowModuleSchemaMap}
 		bind:toolDescription={tool.description}
 		{siblingToolNames}
 	/>
diff --git a/frontend/src/lib/components/flows/content/AiAgentStepInputs.svelte b/frontend/src/lib/components/flows/content/AiAgentStepInputs.svelte
index 31abd3c0b5..c868f65efb 100644
--- a/frontend/src/lib/components/flows/content/AiAgentStepInputs.svelte
+++ b/frontend/src/lib/components/flows/content/AiAgentStepInputs.svelte
@@ -558,6 +558,7 @@
 										{onAddTool}
 										{onDeleteTool}
 										pickerPortal={toolPickerPortal}
+										allowAiAgentTool={!isAgentTool}
 									/>
 								{:else}
 									<!-- Inert rather than merely button-less: every control below writes into
diff --git a/frontend/src/lib/components/flows/content/FlowModuleComponent.svelte b/frontend/src/lib/components/flows/content/FlowModuleComponent.svelte
index f51703dc22..f813207223 100644
--- a/frontend/src/lib/components/flows/content/FlowModuleComponent.svelte
+++ b/frontend/src/lib/components/flows/content/FlowModuleComponent.svelte
@@ -70,7 +70,7 @@
 		signDebugRequest,
 		getDebugErrorMessage
 	} from '$lib/components/debug'
-	import { Bug, Terminal } from 'lucide-svelte'
+	import { Bug, ChevronRight, Terminal } from 'lucide-svelte'
 	import { sendUserToast } from '$lib/utils'
 
 	const {
@@ -130,6 +130,9 @@
 		 *  surface without a graph — the agent editor, which addresses one tool at a time — would
 		 *  offer a row whose click lands nowhere. */
 		noToolNavigation?: boolean
+		/** The agents an agent tool sits under, the step's own first. The header lists them to go
+		 *  back up, since a nested agent's tools have no graph node to reach them from. */
+		agentTrail?: Pick<FlowModule, 'id' | 'summary'>[]
 		toolDescription?: string | undefined
 		siblingToolNames?: string[]
 	}
@@ -151,6 +154,7 @@
 		staticOnly = false,
 		flowModuleSchemaMap = undefined,
 		noToolNavigation = false,
+		agentTrail = undefined,
 		toolDescription = $bindable(undefined),
 		siblingToolNames = undefined
 	}: Props = $props()
@@ -828,6 +832,26 @@
 
 <svelte:window onkeydown={onKeyDown} />
 
+{#snippet agentTrailNav()}
+	<nav
+		aria-label="Breadcrumb"
+		class="flex flex-row flex-wrap items-center gap-0.5 min-w-0 text-xs text-secondary"
+	>
+		{#each agentTrail ?? [] as agent, i (i)}
+			<Button
+				variant="subtle"
+				unifiedSize="2xs"
+				onClick={() => selectionManager.selectId(agent.id, { openPanel: true })}
+				wrapperClasses="min-w-0 shrink"
+				btnClasses="!px-0 !font-normal !text-xs text-secondary hover:text-emphasis hover:underline hover:!bg-transparent min-w-0"
+			>
+				<span class="truncate">{agent.summary || 'AI Agent'}</span>
+			</Button>
+			<ChevronRight size={12} class="text-tertiary shrink-0" />
+		{/each}
+	</nav>
+{/snippet}
+
 {#if flowModule.value}
 	<div class="h-full bg-surface" bind:clientWidth={width}>
 		<FlowCard
@@ -846,6 +870,7 @@
 			on:reload={reloadModule}
 			bind:summary={flowModule.summary}
 			bind:description={toolDescription}
+			trail={agentTrail?.length && !noToolNavigation ? agentTrailNav : undefined}
 			{isAgentTool}
 			{siblingToolNames}
 		>
@@ -1253,6 +1278,10 @@
 															? (detail) =>
 																	flowModuleSchemaMap?.addToolToAgent(flowModule.id, detail)
 															: undefined}
+														onDeleteTool={flowModuleSchemaMap && !agentLinked
+															? (toolId) =>
+																	flowModuleSchemaMap?.deleteAgentTool(flowModule.id, toolId)
+															: undefined}
 													/>
 												{:else}
 													<InputTransformSchemaForm
diff --git a/frontend/src/lib/components/flows/content/FlowModuleWrapper.svelte b/frontend/src/lib/components/flows/content/FlowModuleWrapper.svelte
index febbe5681c..f6ec85e552 100644
--- a/frontend/src/lib/components/flows/content/FlowModuleWrapper.svelte
+++ b/frontend/src/lib/components/flows/content/FlowModuleWrapper.svelte
@@ -26,6 +26,7 @@
 	import type { TriggerContext } from '$lib/components/triggers'
 	import { formatCron } from '$lib/utils'
 	import AgentToolWrapper from './AgentToolWrapper.svelte'
+	import { findAgentToolOwner } from '../agentToolTree'
 	const { selectionManager, flowStateStore, opWorkspace } =
 		getContext<FlowEditorContext>('FlowEditorContext')
 	const selectedId = $derived(selectionManager.getSelectedId())
@@ -66,6 +67,13 @@
 		flowModuleSchemaMap = undefined
 	}: Props = $props()
 
+	// Searched at any depth: a nested agent's tools have no wrapper of their own to render them.
+	const selectedToolOwner = $derived(
+		flowModule.value.type === 'aiagent' && selectedId
+			? findAgentToolOwner([flowModule], selectedId)
+			: undefined
+	)
+
 	function initializePrimaryScheduleForTriggerScript(module: FlowModule) {
 		const primaryIndex = triggersState.triggers.findIndex((t) => t.isPrimary)
 		if (primaryIndex === -1) {
@@ -326,18 +334,19 @@
 		{/if}
 	{/each}
 {:else if flowModule.value.type === 'aiagent'}
-	{#each flowModule.value.tools ?? [] as tool, toolIndex (toolIndex)}
-		{#if selectedId === tool.id}
-			<AgentToolWrapper
-				{noEditor}
-				bind:tool={flowModule.value.tools![toolIndex]}
-				parentModule={flowModule}
-				{previousModule}
-				{enableAi}
-				{forceTestTab}
-				{highlightArg}
-				siblingToolNames={flowModule.value.tools!.map((t) => t.summary ?? '')}
-			/>
-		{/if}
-	{/each}
+	{#if selectedToolOwner}
+		{@const owner = selectedToolOwner}
+		<AgentToolWrapper
+			{noEditor}
+			bind:tool={() => owner.tools[owner.toolIndex], (v) => (owner.tools[owner.toolIndex] = v)}
+			parentModule={owner.agents[owner.agents.length - 1] as FlowModule}
+			{previousModule}
+			{enableAi}
+			{forceTestTab}
+			{highlightArg}
+			siblingToolNames={owner.tools.map((t) => t.summary ?? '')}
+			agentTrail={owner.agents}
+			{flowModuleSchemaMap}
+		/>
+	{/if}
 {/if}
diff --git a/frontend/src/lib/components/flows/map/FlowModuleSchemaMap.svelte b/frontend/src/lib/components/flows/map/FlowModuleSchemaMap.svelte
index 22b74230b4..50149e4cbd 100644
--- a/frontend/src/lib/components/flows/map/FlowModuleSchemaMap.svelte
+++ b/frontend/src/lib/components/flows/map/FlowModuleSchemaMap.svelte
@@ -293,7 +293,7 @@
 		})
 	}
 
-	function requestDelete(ids: string[]) {
+	function requestDelete(ids: string[], selectAfter?: string) {
 		const request = prepareDeleteRequest({
 			ids,
 			flow: flowStore.val,
@@ -304,6 +304,9 @@
 		if (!request) {
 			return
 		}
+		if (selectAfter) {
+			request.plan.selection = { kind: 'select', id: selectAfter }
+		}
 
 		const affectedGroups = request.plan.structureDelete?.affectedGroups ?? []
 
@@ -325,6 +328,13 @@
 		requestDelete(ids)
 	}
 
+	/** Delete a tool from its agent's Tools section, the only place a nested agent's tools can be
+	 *  deleted from. The agent stays selected: a plain delete selects whatever precedes the tool,
+	 *  often a sibling tool, which would take the panel away from the list being edited. */
+	export function deleteAgentTool(agentId: string, toolId: string) {
+		requestDelete([toolId], agentId)
+	}
+
 	// Operates directly on the flat module array (not the structure tree).
 	// Cloned modules are inserted after the originals, intentionally outside any group.
 	export function duplicateMultiple(ids: string[]) {
diff --git a/frontend/src/lib/components/flows/map/InsertModuleInner.svelte b/frontend/src/lib/components/flows/map/InsertModuleInner.svelte
index 7c75d97fab..b539e5788b 100644
--- a/frontend/src/lib/components/flows/map/InsertModuleInner.svelte
+++ b/frontend/src/lib/components/flows/map/InsertModuleInner.svelte
@@ -25,6 +25,9 @@
 		kind?: 'script' | 'trigger' | 'preprocessor' | 'failure'
 		allowTrigger?: boolean
 		toolMode?: boolean
+		/** Off for a tool of a nested agent: the worker runs an agent tool only under a step's own
+		 *  agent, and leaves one nested any deeper out of what the model is offered. */
+		allowAiAgentTool?: boolean
 		/** Narrow layout (450px instead of 650px). Defaults on for the preprocessor
 		 *  and failure pickers; set it when the container cannot fit the wide one. */
 		small?: boolean
@@ -37,6 +40,7 @@
 		kind = 'script',
 		allowTrigger = true,
 		toolMode = false,
+		allowAiAgentTool = true,
 		small: smallProp = undefined
 	}: Props = $props()
 
@@ -230,13 +234,15 @@
 							dispatch('close')
 						}}
 					/>
-					<TopLevelNode
-						label="AI Agent"
-						onSelect={() => {
-							dispatch('pickAiAgentTool')
-							dispatch('close')
-						}}
-					/>
+					{#if allowAiAgentTool}
+						<TopLevelNode
+							label="AI Agent"
+							onSelect={() => {
+								dispatch('pickAiAgentTool')
+								dispatch('close')
+							}}
+						/>
+					{/if}
 				{:else}
 					{#if customUi?.triggers != false && allowTrigger}
 						<TopLevelNode