fix(acp): preserve command reference arguments

packages/ui/acp/src/index.ts

@@ -73,6 +73,7 @@ import {
   type AskUserQuestionRequest,
 } from '@deepseek-ai/dsh-user-interaction'
 import {
+  acpPromptToText,
   acpPromptToReferencedPrompt,
   harnessBlockToAcpContent,
   promptHasUnsupportedContent,
@@ -896,23 +897,16 @@ export function apply(ctx: Context, config: AcpConfig): void {
         if (promptHasUnsupportedContent(params.prompt)) {
           throw invalidParams('only text and resource_link prompt content is supported; image/audio/embedded resource blocks are rejected rather than silently dropped')
         }
-        let referencedPrompt: ReturnType<typeof acpPromptToReferencedPrompt>
-        try {
-          referencedPrompt = acpPromptToReferencedPrompt(params.prompt)
-        } catch (error: unknown) {
-          throw invalidParams(`invalid session reference: ${renderThrown(error)}`)
-        }
-        const { text } = referencedPrompt
-        if (text.trim().length === 0) {
+        const flattenedText = acpPromptToText(params.prompt)
+        if (flattenedText.trim().length === 0) {
           // Reject up front rather than calling send(): an empty prompt would
           // queue no work, no turn would start, and the RPC would hang forever
           // waiting for a settle that never comes.
           throw invalidParams('empty prompt')
         }
-        // ACP command prompts may carry additional supported content blocks.
-        // The same lossless flattening used for model prompts supplies their
-        // unstructured command input; unsupported kinds were rejected above.
-        const commandLine = text.startsWith('/') ? text : undefined
+        // Direct commands consume ordinary ACP flattening before reference
+        // extraction, so URI-shaped arguments remain opaque to the bridge.
+        const commandLine = flattenedText.startsWith('/') ? flattenedText : undefined
         if (commandLine !== undefined) {
           const controller = new AbortController()
           rec.commandAbort = controller
@@ -955,6 +949,13 @@ export function apply(ctx: Context, config: AcpConfig): void {
             rec.commandAbort = undefined
           }
         }
+        let referencedPrompt: ReturnType<typeof acpPromptToReferencedPrompt>
+        try {
+          referencedPrompt = acpPromptToReferencedPrompt(params.prompt)
+        } catch (error: unknown) {
+          throw invalidParams(`invalid session reference: ${renderThrown(error)}`)
+        }
+        const { text } = referencedPrompt
         let preparedContent: ContentBlock[] = [{ type: 'text', text }]
         let preparedContexts: NonNullable<Parameters<Agent['send']>[1]>['contexts'] = []
         if (referencedPrompt.references.length > 0) {

packages/ui/acp/tests/commands.spec.ts

@@ -4,6 +4,7 @@ import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { PROTOCOL_VERSION } from '@agentclientprotocol/sdk'
 import { SessionId } from '@deepseek-ai/dsh-session'
+import { encodeSessionReferenceUri } from '@deepseek-ai/dsh-session-reference'
 import { makeBridgeHarness, textResponse, type BridgeHarness } from './harness.ts'
 
 function commandUpdates(harness: BridgeHarness, sessionId: string) {
@@ -195,6 +196,28 @@ describe('ACP plugin commands', () => {
     expect(harness.adapter.requests).toHaveLength(0)
   })
 
+  it('keeps session-reference syntax opaque in direct command arguments', async () => {
+    harness = await makeBridgeHarness({ storageDir })
+    const command = vi.fn(() => ({ kind: 'success' as const }))
+    harness.ctx.commands.register({ name: 'direct', description: 'Direct', handler: command })
+    await harness.client.initialize({ protocolVersion: PROTOCOL_VERSION, clientCapabilities: {} })
+    const { sessionId } = await harness.client.newSession({ cwd: process.cwd(), mcpServers: [] })
+    const sourceUri = encodeSessionReferenceUri(SessionId('source'))
+
+    await expect(harness.client.prompt({
+      sessionId,
+      prompt: [
+        { type: 'text', text: `/direct valid=${sourceUri} malformed=dsh-session:IiJ` },
+        { type: 'resource_link', name: 'source', uri: sourceUri },
+      ],
+    })).resolves.toEqual({ stopReason: 'end_turn' })
+    expect(command).toHaveBeenCalledWith(expect.objectContaining({
+      rawInput: ` valid=${sourceUri} malformed=dsh-session:IiJ\n[resource_link name="source" uri=${JSON.stringify(sourceUri)}]\n`,
+    }))
+    expect(harness.adapter.requests).toHaveLength(0)
+    expect(harness.ctx.agents.get(SessionId(sessionId))?.session.events).toHaveLength(0)
+  })
+
   it('maps session cancellation to the in-flight command signal and isolates other sessions', async () => {
     harness = await makeBridgeHarness({ storageDir })
     let started!: () => void