fix: pass arguments to commands without explicit placeholders (#9606)

packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx

@@ -546,16 +546,22 @@ export function Prompt(props: PromptProps) {
     } else if (
       inputText.startsWith("/") &&
       iife(() => {
-        const command = inputText.split(" ")[0].slice(1)
+        const firstLine = inputText.split("\n")[0]
-        console.log(command)
+        const command = firstLine.split(" ")[0].slice(1)
         return sync.data.command.some((x) => x.name === command)
       })
     ) {
-      let [command, ...args] = inputText.split(" ")
+      // Parse command from first line, preserve multi-line content in arguments
+      const firstLineEnd = inputText.indexOf("\n")
+      const firstLine = firstLineEnd === -1 ? inputText : inputText.slice(0, firstLineEnd)
+      const [command, ...firstLineArgs] = firstLine.split(" ")
+      const restOfInput = firstLineEnd === -1 ? "" : inputText.slice(firstLineEnd + 1)
+      const args = firstLineArgs.join(" ") + (restOfInput ? "\n" + restOfInput : "")
+
       sdk.client.session.command({
         sessionID,
         command: command.slice(1),
-        arguments: args.join(" "),
+        arguments: args,
         agent: local.agent.current().name,
         model: `${selectedModel.providerID}/${selectedModel.modelID}`,
         messageID,

packages/opencode/src/session/prompt.ts

@@ -1627,8 +1627,15 @@ NOTE: At any point in time through this workflow you should feel free to ask the
       if (position === last) return args.slice(argIndex).join(" ")
       return args[argIndex]
     })
+    const usesArgumentsPlaceholder = templateCommand.includes("$ARGUMENTS")
     let template = withArgs.replaceAll("$ARGUMENTS", input.arguments)
 
+    // If command doesn't explicitly handle arguments (no $N or $ARGUMENTS placeholders)
+    // but user provided arguments, append them to the template
+    if (placeholders.length === 0 && !usesArgumentsPlaceholder && input.arguments.trim()) {
+      template = template + "\n\n" + input.arguments
+    }
+
     const shell = ConfigMarkdown.shell(template)
     if (shell.length > 0) {
       const results = await Promise.all(