diff --git a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/tool-input/tool-input.tsx b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/tool-input/tool-input.tsx
index b3d9cab9d4..6afbe1484c 100644
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/tool-input/tool-input.tsx
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/tool-input/tool-input.tsx
@@ -557,7 +557,7 @@ function FileUploadSyncWrapper({
   )
 }
 
-function ChannelSelectorSyncWrapper({
+function SlackSelectorSyncWrapper({
   blockId,
   paramId,
   value,
@@ -565,6 +565,7 @@ function ChannelSelectorSyncWrapper({
   uiComponent,
   disabled,
   previewContextValues,
+  selectorType,
 }: {
   blockId: string
   paramId: string
@@ -573,6 +574,7 @@ function ChannelSelectorSyncWrapper({
   uiComponent: any
   disabled: boolean
   previewContextValues?: Record<string, any>
+  selectorType: 'channel-selector' | 'user-selector'
 }) {
   return (
     <GenericSyncWrapper blockId={blockId} paramId={paramId} value={value} onChange={onChange}>
@@ -580,7 +582,7 @@ function ChannelSelectorSyncWrapper({
         blockId={blockId}
         subBlock={{
           id: paramId,
-          type: 'channel-selector' as const,
+          type: selectorType,
           title: paramId,
           serviceId: uiComponent.serviceId,
           placeholder: uiComponent.placeholder,
@@ -1952,7 +1954,7 @@ export function ToolInput({
 
       case 'channel-selector':
         return (
-          <ChannelSelectorSyncWrapper
+          <SlackSelectorSyncWrapper
             blockId={blockId}
             paramId={param.id}
             value={value}
@@ -1960,6 +1962,21 @@ export function ToolInput({
             uiComponent={uiComponent}
             disabled={disabled}
             previewContextValues={currentToolParams as any}
+            selectorType='channel-selector'
+          />
+        )
+
+      case 'user-selector':
+        return (
+          <SlackSelectorSyncWrapper
+            blockId={blockId}
+            paramId={param.id}
+            value={value}
+            onChange={onChange}
+            uiComponent={uiComponent}
+            disabled={disabled}
+            previewContextValues={currentToolParams as any}
+            selectorType='user-selector'
           />
         )
 
diff --git a/apps/sim/lib/environment/utils.ts b/apps/sim/lib/environment/utils.ts
index 8e56e264e3..ecff2660a2 100644
--- a/apps/sim/lib/environment/utils.ts
+++ b/apps/sim/lib/environment/utils.ts
@@ -143,6 +143,7 @@ export async function ensureBlockEnvVarsResolvable(
   options: { requestId?: string } = {}
 ): Promise<void> {
   const requestId = options.requestId
+  const envVarPattern = createEnvVarPattern()
   await Promise.all(
     Object.values(blocks).map(async (block) => {
       const subBlocks = block.subBlocks ?? {}
@@ -157,7 +158,6 @@ export async function ensureBlockEnvVarsResolvable(
             return
           }
 
-          const envVarPattern = createEnvVarPattern()
           const matches = value.match(envVarPattern)
           if (!matches) {
             return
diff --git a/apps/sim/tools/slack/message.ts b/apps/sim/tools/slack/message.ts
index d8c9e36b87..1e1d3b0c9d 100644
--- a/apps/sim/tools/slack/message.ts
+++ b/apps/sim/tools/slack/message.ts
@@ -20,6 +20,12 @@ export const slackMessageTool: ToolConfig<SlackMessageParams, SlackMessageRespon
       visibility: 'user-only',
       description: 'Authentication method: oauth or bot_token',
     },
+    destinationType: {
+      type: 'string',
+      required: false,
+      visibility: 'user-only',
+      description: 'Destination type: channel or dm',
+    },
     botToken: {
       type: 'string',
       required: false,
@@ -38,11 +44,11 @@ export const slackMessageTool: ToolConfig<SlackMessageParams, SlackMessageRespon
       visibility: 'user-only',
       description: 'Target Slack channel (e.g., #general)',
     },
-    userId: {
+    dmUserId: {
       type: 'string',
       required: false,
       visibility: 'user-only',
-      description: 'Target Slack user ID for direct messages (e.g., U1234567890)',
+      description: 'Target Slack user for direct messages',
     },
     text: {
       type: 'string',
@@ -71,10 +77,11 @@ export const slackMessageTool: ToolConfig<SlackMessageParams, SlackMessageRespon
       'Content-Type': 'application/json',
     }),
     body: (params: SlackMessageParams) => {
+      const isDM = params.destinationType === 'dm'
       return {
         accessToken: params.accessToken || params.botToken,
-        channel: params.channel,
-        userId: params.userId,
+        channel: isDM ? undefined : params.channel,
+        userId: isDM ? params.dmUserId : params.userId,
         text: params.text,
         thread_ts: params.thread_ts || undefined,
         files: params.files || null,
diff --git a/apps/sim/tools/slack/message_reader.ts b/apps/sim/tools/slack/message_reader.ts
index b7bdc258f0..3170409239 100644
--- a/apps/sim/tools/slack/message_reader.ts
+++ b/apps/sim/tools/slack/message_reader.ts
@@ -23,6 +23,12 @@ export const slackMessageReaderTool: ToolConfig<
       visibility: 'user-only',
       description: 'Authentication method: oauth or bot_token',
     },
+    destinationType: {
+      type: 'string',
+      required: false,
+      visibility: 'user-only',
+      description: 'Destination type: channel or dm',
+    },
     botToken: {
       type: 'string',
       required: false,
@@ -41,11 +47,11 @@ export const slackMessageReaderTool: ToolConfig<
       visibility: 'user-only',
       description: 'Slack channel to read messages from (e.g., #general)',
     },
-    userId: {
+    dmUserId: {
       type: 'string',
       required: false,
       visibility: 'user-only',
-      description: 'User ID for DM conversation (e.g., U1234567890)',
+      description: 'Target Slack user for DM conversation',
     },
     limit: {
       type: 'number',
@@ -73,14 +79,17 @@ export const slackMessageReaderTool: ToolConfig<
     headers: () => ({
       'Content-Type': 'application/json',
     }),
-    body: (params: SlackMessageReaderParams) => ({
-      accessToken: params.accessToken || params.botToken,
-      channel: params.channel,
-      userId: params.userId,
-      limit: params.limit,
-      oldest: params.oldest,
-      latest: params.latest,
-    }),
+    body: (params: SlackMessageReaderParams) => {
+      const isDM = params.destinationType === 'dm'
+      return {
+        accessToken: params.accessToken || params.botToken,
+        channel: isDM ? undefined : params.channel,
+        userId: isDM ? params.dmUserId : params.userId,
+        limit: params.limit,
+        oldest: params.oldest,
+        latest: params.latest,
+      }
+    },
   },
 
   transformResponse: async (response: Response) => {
diff --git a/apps/sim/tools/slack/types.ts b/apps/sim/tools/slack/types.ts
index 4271409aa0..55dd9f7d20 100644
--- a/apps/sim/tools/slack/types.ts
+++ b/apps/sim/tools/slack/types.ts
@@ -7,7 +7,9 @@ export interface SlackBaseParams {
 }
 
 export interface SlackMessageParams extends SlackBaseParams {
+  destinationType?: 'channel' | 'dm'
   channel?: string
+  dmUserId?: string
   userId?: string
   text: string
   thread_ts?: string
@@ -22,7 +24,9 @@ export interface SlackCanvasParams extends SlackBaseParams {
 }
 
 export interface SlackMessageReaderParams extends SlackBaseParams {
+  destinationType?: 'channel' | 'dm'
   channel?: string
+  dmUserId?: string
   userId?: string
   limit?: number
   oldest?: string