diff --git a/packages/app/src/components/prompt-input.tsx b/packages/app/src/components/prompt-input.tsx
index a5655902a47..67fa6ea82ec 100644
--- a/packages/app/src/components/prompt-input.tsx
+++ b/packages/app/src/components/prompt-input.tsx
@@ -24,6 +24,7 @@ import {
   usePrompt,
   ImageAttachmentPart,
   AgentPart,
+  CommandPart,
   FileAttachmentPart,
 } from "@/context/prompt"
 import { useLayout } from "@/context/layout"
@@ -210,6 +211,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
       if (part.type === "text") return { ...part }
       if (part.type === "image") return { ...part }
       if (part.type === "agent") return { ...part }
+      if (part.type === "command") return { ...part }
       return {
         ...part,
         selection: part.selection ? { ...part.selection } : undefined,
@@ -428,10 +430,17 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
     setStore("popover", null)
 
     if (cmd.type === "custom") {
-      const text = `/${cmd.trigger} `
+      const content = `/${cmd.trigger}`
+      const commandPart: CommandPart = {
+        type: "command",
+        name: cmd.trigger,
+        content,
+        start: 0,
+        end: content.length,
+      }
+      const textPart = { type: "text" as const, content: " ", start: content.length, end: content.length + 1 }
       editorRef.innerHTML = ""
-      editorRef.textContent = text
-      prompt.set([{ type: "text", content: text, start: 0, end: text.length }], text.length)
+      prompt.set([commandPart, textPart], content.length + 1)
       requestAnimationFrame(() => {
         editorRef.focus()
         const range = document.createRange()
@@ -462,12 +471,13 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
     onSelect: handleSlashSelect,
   })
 
-  const createPill = (part: FileAttachmentPart | AgentPart) => {
+  const createPill = (part: FileAttachmentPart | AgentPart | CommandPart) => {
     const pill = document.createElement("span")
     pill.textContent = part.content
     pill.setAttribute("data-type", part.type)
     if (part.type === "file") pill.setAttribute("data-path", part.path)
     if (part.type === "agent") pill.setAttribute("data-name", part.name)
+    if (part.type === "command") pill.setAttribute("data-name", part.name)
     pill.setAttribute("contenteditable", "false")
     pill.style.userSelect = "text"
     pill.style.cursor = "default"
@@ -493,6 +503,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
       const el = node as HTMLElement
       if (el.dataset.type === "file") return true
       if (el.dataset.type === "agent") return true
+      if (el.dataset.type === "command") return true
       return el.tagName === "BR"
     })
 
@@ -503,7 +514,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
         editorRef.appendChild(createTextFragment(part.content))
         continue
       }
-      if (part.type === "file" || part.type === "agent") {
+      if (part.type === "file" || part.type === "agent" || part.type === "command") {
         editorRef.appendChild(createPill(part))
       }
     }
@@ -588,6 +599,18 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
       position += content.length
     }
 
+    const pushCommand = (cmd: HTMLElement) => {
+      const content = cmd.textContent ?? ""
+      parts.push({
+        type: "command",
+        name: cmd.dataset.name!,
+        content,
+        start: position,
+        end: position + content.length,
+      })
+      position += content.length
+    }
+
     const visit = (node: Node) => {
       if (node.nodeType === Node.TEXT_NODE) {
         buffer += node.textContent ?? ""
@@ -606,6 +629,11 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
         pushAgent(el)
         return
       }
+      if (el.dataset.type === "command") {
+        flushText()
+        pushCommand(el)
+        return
+      }
       if (el.tagName === "BR") {
         buffer += "\n"
         return
@@ -656,8 +684,49 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
     const shellMode = store.mode === "shell"
 
     if (!shellMode) {
+      const commandPartIndex = rawParts.findIndex((p) => p.type === "command")
+      if (commandPartIndex > 0) {
+        const textPart = {
+          type: "text" as const,
+          content: rawText,
+          start: 0,
+          end: rawText.length,
+        }
+        setStore("popover", null)
+        prompt.set([textPart], cursorPosition)
+        queueScroll()
+        return
+      }
+
       const atMatch = rawText.substring(0, cursorPosition).match(/@(\S*)$/)
       const slashMatch = rawText.match(/^\/(\S*)$/)
+      const slashWithSpaceMatch = rawText.match(/^\/(\S+)\s/)
+
+      if (slashWithSpaceMatch && !rawParts.some((p) => p.type === "command")) {
+        const cmdName = slashWithSpaceMatch[1]
+        const customCmd = sync.data.command.find((c) => c.name === cmdName)
+        if (customCmd) {
+          const content = `/${cmdName}`
+          const commandPart: CommandPart = {
+            type: "command",
+            name: cmdName,
+            content,
+            start: 0,
+            end: content.length,
+          }
+          const afterCommand = rawText.slice(content.length)
+          const textPart = {
+            type: "text" as const,
+            content: afterCommand,
+            start: content.length,
+            end: content.length + afterCommand.length,
+          }
+          setStore("popover", null)
+          prompt.set([commandPart, textPart], cursorPosition)
+          queueScroll()
+          return
+        }
+      }
 
       if (atMatch) {
         atOnInput(atMatch[1])
@@ -690,7 +759,9 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
       const isText = node.nodeType === Node.TEXT_NODE
       const isPill =
         node.nodeType === Node.ELEMENT_NODE &&
-        ((node as HTMLElement).dataset.type === "file" || (node as HTMLElement).dataset.type === "agent")
+        ((node as HTMLElement).dataset.type === "file" ||
+          (node as HTMLElement).dataset.type === "agent" ||
+          (node as HTMLElement).dataset.type === "command")
       const isBreak = node.nodeType === Node.ELEMENT_NODE && (node as HTMLElement).tagName === "BR"
 
       if (isText && remaining <= length) {
@@ -1515,6 +1586,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
               "w-full px-5 py-3 pr-12 text-14-regular text-text-strong focus:outline-none whitespace-pre-wrap": true,
               "[&_[data-type=file]]:text-syntax-property": true,
               "[&_[data-type=agent]]:text-syntax-type": true,
+              "[&_[data-type=command]]:text-syntax-string": true,
               "font-mono!": store.mode === "shell",
             }}
           />
@@ -1714,7 +1786,9 @@ function setCursorPosition(parent: HTMLElement, position: number) {
     const isText = node.nodeType === Node.TEXT_NODE
     const isPill =
       node.nodeType === Node.ELEMENT_NODE &&
-      ((node as HTMLElement).dataset.type === "file" || (node as HTMLElement).dataset.type === "agent")
+      ((node as HTMLElement).dataset.type === "file" ||
+        (node as HTMLElement).dataset.type === "agent" ||
+        (node as HTMLElement).dataset.type === "command")
     const isBreak = node.nodeType === Node.ELEMENT_NODE && (node as HTMLElement).tagName === "BR"
 
     if (isText && remaining <= length) {
diff --git a/packages/app/src/context/prompt.tsx b/packages/app/src/context/prompt.tsx
index 2fa4571e890..a189b089eb2 100644
--- a/packages/app/src/context/prompt.tsx
+++ b/packages/app/src/context/prompt.tsx
@@ -26,6 +26,11 @@ export interface AgentPart extends PartBase {
   name: string
 }
 
+export interface CommandPart extends PartBase {
+  type: "command"
+  name: string
+}
+
 export interface ImageAttachmentPart {
   type: "image"
   id: string
@@ -34,7 +39,7 @@ export interface ImageAttachmentPart {
   dataUrl: string
 }
 
-export type ContentPart = TextPart | FileAttachmentPart | AgentPart | ImageAttachmentPart
+export type ContentPart = TextPart | FileAttachmentPart | AgentPart | CommandPart | ImageAttachmentPart
 export type Prompt = ContentPart[]
 
 export type FileContextItem = {
@@ -73,6 +78,9 @@ export function isPromptEqual(promptA: Prompt, promptB: Prompt): boolean {
     if (partA.type === "agent" && partA.name !== (partB as AgentPart).name) {
       return false
     }
+    if (partA.type === "command" && partA.name !== (partB as CommandPart).name) {
+      return false
+    }
     if (partA.type === "image" && partA.id !== (partB as ImageAttachmentPart).id) {
       return false
     }
@@ -89,6 +97,7 @@ function clonePart(part: ContentPart): ContentPart {
   if (part.type === "text") return { ...part }
   if (part.type === "image") return { ...part }
   if (part.type === "agent") return { ...part }
+  if (part.type === "command") return { ...part }
   return {
     ...part,
     selection: cloneSelection(part.selection),
diff --git a/packages/opencode/src/session/message-v2.ts b/packages/opencode/src/session/message-v2.ts
index 2dff17a5efa..28af8c43bc5 100644
--- a/packages/opencode/src/session/message-v2.ts
+++ b/packages/opencode/src/session/message-v2.ts
@@ -172,6 +172,14 @@ export namespace MessageV2 {
   })
   export type SubtaskPart = z.infer<typeof SubtaskPart>
 
+  export const CommandPart = PartBase.extend({
+    type: z.literal("command"),
+    command: z.string(),
+  }).meta({
+    ref: "CommandPart",
+  })
+  export type CommandPart = z.infer<typeof CommandPart>
+
   export const RetryPart = PartBase.extend({
     type: z.literal("retry"),
     attempt: z.number(),
@@ -334,6 +342,7 @@ export namespace MessageV2 {
       AgentPart,
       RetryPart,
       CompactionPart,
+      CommandPart,
     ])
     .meta({
       ref: "Part",
diff --git a/packages/opencode/src/session/prompt.ts b/packages/opencode/src/session/prompt.ts
index f891612272c..839bfc06a12 100644
--- a/packages/opencode/src/session/prompt.ts
+++ b/packages/opencode/src/session/prompt.ts
@@ -142,6 +142,16 @@ export namespace SessionPrompt {
           .meta({
             ref: "SubtaskPartInput",
           }),
+        MessageV2.CommandPart.omit({
+          messageID: true,
+          sessionID: true,
+        })
+          .partial({
+            id: true,
+          })
+          .meta({
+            ref: "CommandPartInput",
+          }),
       ]),
     ),
   })
@@ -1545,8 +1555,12 @@ export namespace SessionPrompt {
     }
 
     const templateParts = await resolvePromptParts(template)
-    const parts =
-      (agent.mode === "subagent" && command.subtask !== false) || command.subtask === true
+    const parts = [
+      {
+        type: "command" as const,
+        command: `/${input.command}${input.arguments ? " " + input.arguments : ""}`,
+      },
+      ...((agent.mode === "subagent" && command.subtask !== false) || command.subtask === true
         ? [
             {
               type: "subtask" as const,
@@ -1557,7 +1571,8 @@ export namespace SessionPrompt {
               prompt: templateParts.find((y) => y.type === "text")?.text ?? "",
             },
           ]
-        : [...templateParts, ...(input.parts ?? [])]
+        : [...templateParts, ...(input.parts ?? [])]),
+    ]
 
     const result = (await prompt({
       sessionID: input.sessionID,
diff --git a/packages/sdk/js/src/v2/gen/sdk.gen.ts b/packages/sdk/js/src/v2/gen/sdk.gen.ts
index a26cefb176f..ac8ffaaba64 100644
--- a/packages/sdk/js/src/v2/gen/sdk.gen.ts
+++ b/packages/sdk/js/src/v2/gen/sdk.gen.ts
@@ -11,6 +11,7 @@ import type {
   AuthSetErrors,
   AuthSetResponses,
   CommandListResponses,
+  CommandPartInput,
   Config as Config2,
   ConfigGetResponses,
   ConfigProvidersResponses,
@@ -1314,7 +1315,7 @@ export class Session extends HeyApiClient {
       }
       system?: string
       variant?: string
-      parts?: Array<TextPartInput | FilePartInput | AgentPartInput | SubtaskPartInput>
+      parts?: Array<TextPartInput | FilePartInput | AgentPartInput | SubtaskPartInput | CommandPartInput>
     },
     options?: Options<never, ThrowOnError>,
   ) {
@@ -1402,7 +1403,7 @@ export class Session extends HeyApiClient {
       }
       system?: string
       variant?: string
-      parts?: Array<TextPartInput | FilePartInput | AgentPartInput | SubtaskPartInput>
+      parts?: Array<TextPartInput | FilePartInput | AgentPartInput | SubtaskPartInput | CommandPartInput>
     },
     options?: Options<never, ThrowOnError>,
   ) {
diff --git a/packages/sdk/js/src/v2/gen/types.gen.ts b/packages/sdk/js/src/v2/gen/types.gen.ts
index 97a695162ed..0b216fd83fc 100644
--- a/packages/sdk/js/src/v2/gen/types.gen.ts
+++ b/packages/sdk/js/src/v2/gen/types.gen.ts
@@ -419,6 +419,14 @@ export type CompactionPart = {
   auto: boolean
 }
 
+export type CommandPart = {
+  id: string
+  sessionID: string
+  messageID: string
+  type: "command"
+  command: string
+}
+
 export type Part =
   | TextPart
   | {
@@ -441,6 +449,7 @@ export type Part =
   | AgentPart
   | RetryPart
   | CompactionPart
+  | CommandPart
 
 export type EventMessagePartUpdated = {
   type: "message.part.updated"
@@ -1763,6 +1772,12 @@ export type SubtaskPartInput = {
   command?: string
 }
 
+export type CommandPartInput = {
+  id?: string
+  type: "command"
+  command: string
+}
+
 export type Command = {
   name: string
   description?: string
@@ -3066,7 +3081,7 @@ export type SessionPromptData = {
     }
     system?: string
     variant?: string
-    parts: Array<TextPartInput | FilePartInput | AgentPartInput | SubtaskPartInput>
+    parts: Array<TextPartInput | FilePartInput | AgentPartInput | SubtaskPartInput | CommandPartInput>
   }
   path: {
     /**
@@ -3253,7 +3268,7 @@ export type SessionPromptAsyncData = {
     }
     system?: string
     variant?: string
-    parts: Array<TextPartInput | FilePartInput | AgentPartInput | SubtaskPartInput>
+    parts: Array<TextPartInput | FilePartInput | AgentPartInput | SubtaskPartInput | CommandPartInput>
   }
   path: {
     /**
diff --git a/packages/sdk/openapi.json b/packages/sdk/openapi.json
index f697f6e3f3e..a2ff9a3effc 100644
--- a/packages/sdk/openapi.json
+++ b/packages/sdk/openapi.json
@@ -2182,6 +2182,9 @@
                         },
                         {
                           "$ref": "#/components/schemas/SubtaskPartInput"
+                        },
+                        {
+                          "$ref": "#/components/schemas/CommandPartInput"
                         }
                       ]
                     }
@@ -2558,6 +2561,9 @@
                         },
                         {
                           "$ref": "#/components/schemas/SubtaskPartInput"
+                        },
+                        {
+                          "$ref": "#/components/schemas/CommandPartInput"
                         }
                       ]
                     }
@@ -6620,6 +6626,28 @@
         },
         "required": ["id", "sessionID", "messageID", "type", "auto"]
       },
+      "CommandPart": {
+        "type": "object",
+        "properties": {
+          "id": {
+            "type": "string"
+          },
+          "sessionID": {
+            "type": "string"
+          },
+          "messageID": {
+            "type": "string"
+          },
+          "type": {
+            "type": "string",
+            "const": "command"
+          },
+          "command": {
+            "type": "string"
+          }
+        },
+        "required": ["id", "sessionID", "messageID", "type", "command"]
+      },
       "Part": {
         "anyOf": [
           {
@@ -6685,6 +6713,9 @@
           },
           {
             "$ref": "#/components/schemas/CompactionPart"
+          },
+          {
+            "$ref": "#/components/schemas/CommandPart"
           }
         ]
       },
@@ -9427,6 +9458,22 @@
         },
         "required": ["type", "prompt", "description", "agent"]
       },
+      "CommandPartInput": {
+        "type": "object",
+        "properties": {
+          "id": {
+            "type": "string"
+          },
+          "type": {
+            "type": "string",
+            "const": "command"
+          },
+          "command": {
+            "type": "string"
+          }
+        },
+        "required": ["type", "command"]
+      },
       "Command": {
         "type": "object",
         "properties": {
diff --git a/packages/ui/src/components/message-part.tsx b/packages/ui/src/components/message-part.tsx
index 8102c2ce715..f8a30ff3099 100644
--- a/packages/ui/src/components/message-part.tsx
+++ b/packages/ui/src/components/message-part.tsx
@@ -14,6 +14,7 @@ import { Dynamic } from "solid-js/web"
 import {
   AgentPart,
   AssistantMessage,
+  CommandPart,
   FilePart,
   Message as MessageType,
   Part as PartType,
@@ -276,9 +277,26 @@ export function AssistantMessageDisplay(props: { message: AssistantMessage; part
   return <For each={filteredParts()}>{(part) => <Part part={part} message={props.message} />}</For>
 }
 
+function CommandDisplay(props: { command: string }) {
+  const parts = createMemo(() => {
+    const match = props.command.match(/^(\/\S+)(.*)$/)
+    if (!match) return { command: props.command, args: "" }
+    return { command: match[1], args: match[2] }
+  })
+
+  return (
+    <span>
+      <span class="text-syntax-string">{parts().command}</span>
+      {parts().args}
+    </span>
+  )
+}
+
 export function UserMessageDisplay(props: { message: UserMessage; parts: PartType[] }) {
   const dialog = useDialog()
 
+  const commandPart = createMemo(() => props.parts?.find((p) => p.type === "command") as CommandPart | undefined)
+
   const textPart = createMemo(
     () => props.parts?.find((p) => p.type === "text" && !(p as TextPart).synthetic) as TextPart | undefined,
   )
@@ -338,6 +356,13 @@ export function UserMessageDisplay(props: { message: UserMessage; parts: PartTyp
           </For>
         </div>
       </Show>
+      <Show when={commandPart()}>
+        {(cmd) => (
+          <div data-slot="user-message-text">
+            <CommandDisplay command={cmd().command} />
+          </div>
+        )}
+      </Show>
       <Show when={text()}>
         <div data-slot="user-message-text">
           <HighlightedText text={text()} references={inlineFiles()} agents={agents()} />