Add web multimodal image attachments

packages/llm/llm-deepseek/src/adapter.ts

@@ -116,6 +116,8 @@ export class DeepSeekAdapter extends LlmAdapter {
       id: model.id,
       name: model.name ?? model.id,
       ...model.description === undefined ? {} : { description: model.description },
+      inputModalities: ['text'],
+      outputModalities: ['text'],
     })))
   }
 

packages/llm/llm-deepseek/src/serialize.ts

@@ -2,10 +2,12 @@
  * Serialize harness messages into DeepSeek chat completions. User text is joined; assistant text
  * becomes `content`, tool calls become `tool_calls`, and tool results become separate tool messages.
  * Assistant reasoning is replayed as `reasoning_content` only on tool-call turns, as required by
- * thinking-mode passback. Unknown declaration-merged block types are skipped rather than rejected.
+ * thinking-mode passback. Core image blocks are rejected explicitly because this wire route is text-only;
+ * unknown declaration-merged block types retain the adapter's documented extension fallback.
  * @module dsh-llm-deepseek/serialize
  */
 
+import { LlmError } from '@deepseek-ai/dsh-llm'
 import type { ContentBlock, GenerateOptions, Message } from '@deepseek-ai/dsh-llm'
 import type { WireMessage, WireRequest, WireTool } from './types.ts'
 
@@ -23,6 +25,16 @@ function flattenText(blocks: ContentBlock[]): string {
     .join('')
 }
 
+/** Reject core image content before any text-flattening path can silently erase it. */
+function assertTextOnly(blocks: readonly ContentBlock[]): void {
+  for (const block of blocks) {
+    if (block.type === 'image') {
+      throw new LlmError('The DeepSeek chat-completions adapter does not support image content.', 'UNSUPPORTED_CONTENT')
+    }
+    if (block.type === 'tool-result') assertTextOnly(block.content)
+  }
+}
+
 /** Serialize one assistant message (text + reasoning + tool calls). */
 function serializeAssistant(message: Message): WireMessage {
   const text = flattenText(message.content)
@@ -68,6 +80,7 @@ function serializeAssistant(message: Message): WireMessage {
 export function serializeMessages(messages: Message[]): WireMessage[] {
   const wire: WireMessage[] = []
   for (const message of messages) {
+    assertTextOnly(message.content)
     if (message.role === 'system') {
       wire.push({ role: 'system', content: flattenText(message.content) })
       continue

packages/llm/llm-deepseek/tests/adapter.spec.ts

@@ -528,8 +528,8 @@ describe('plugin registration and config', () => {
     await ctx.plugin(LlmDeepSeek, { apiKey: 'k', baseURL: 'http://127.0.0.1:1' })
     expect(ctx.llm.listProviders()).toEqual([{ id: 'deepseek', name: 'DeepSeek' }])
     await expect(ctx.llm.listModels('deepseek')).resolves.toEqual([
-      { provider: 'deepseek', id: 'deepseek-v4-flash', name: 'deepseek-v4-flash' },
-      { provider: 'deepseek', id: 'deepseek-v4-pro', name: 'deepseek-v4-pro' },
+      { provider: 'deepseek', id: 'deepseek-v4-flash', name: 'deepseek-v4-flash', inputModalities: ['text'], outputModalities: ['text'] },
+      { provider: 'deepseek', id: 'deepseek-v4-pro', name: 'deepseek-v4-pro', inputModalities: ['text'], outputModalities: ['text'] },
     ])
     await expect(ctx.llm.resolveModelContext('deepseek', 'deepseek-v4-flash'))
       .resolves.toEqual({ contextWindow: 128_000 })
@@ -540,8 +540,8 @@ describe('plugin registration and config', () => {
     await ctx.plugin(LlmService)
     LlmDeepSeek.apply(ctx, { apiKey: 'k', baseURL: 'http://127.0.0.1:1' })
     await expect(ctx.llm.listModels('deepseek')).resolves.toEqual([
-      { provider: 'deepseek', id: 'deepseek-v4-flash', name: 'deepseek-v4-flash' },
-      { provider: 'deepseek', id: 'deepseek-v4-pro', name: 'deepseek-v4-pro' },
+      { provider: 'deepseek', id: 'deepseek-v4-flash', name: 'deepseek-v4-flash', inputModalities: ['text'], outputModalities: ['text'] },
+      { provider: 'deepseek', id: 'deepseek-v4-pro', name: 'deepseek-v4-pro', inputModalities: ['text'], outputModalities: ['text'] },
     ])
   })
 
@@ -562,8 +562,8 @@ describe('plugin registration and config', () => {
       ],
     })
     await expect(ctx.llm.listModels('deepseek')).resolves.toEqual([
-      { provider: 'deepseek', id: 'private-fast', name: 'private-fast' },
-      { provider: 'deepseek', id: 'private-reasoner', name: 'Private Reasoner', description: 'Higher reasoning budget' },
+      { provider: 'deepseek', id: 'private-fast', name: 'private-fast', inputModalities: ['text'], outputModalities: ['text'] },
+      { provider: 'deepseek', id: 'private-reasoner', name: 'Private Reasoner', description: 'Higher reasoning budget', inputModalities: ['text'], outputModalities: ['text'] },
     ])
     await expect(ctx.llm.resolveModelContext('deepseek', 'private-fast'))
       .resolves.toEqual({ contextWindow: 32_000 })

packages/llm/llm-deepseek/tests/serialize.spec.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import { CallId } from '@deepseek-ai/dsh-llm'
+import { AttachmentId } from '@deepseek-ai/dsh-attachment'
 import type { ContentBlock, GenerateOptions, Message } from '@deepseek-ai/dsh-llm'
 import { serializeMessages, serializeRequest } from '../src/serialize.ts'
 
@@ -123,6 +124,19 @@ describe('serializeMessages', () => {
     expect(wire).toEqual([{ role: 'user', content: 'see chart' }])
   })
 
+  it('rejects image blocks instead of silently flattening them away', () => {
+    expect(() => serializeMessages([{
+      role: 'user',
+      content: [{
+        type: 'image',
+        attachment: {
+          attachmentId: AttachmentId(`sha256:${'a'.repeat(64)}`),
+          mediaType: 'image/png', bytes: 68, width: 1, height: 1,
+        },
+      }],
+    }])).toThrow(expect.objectContaining({ code: 'UNSUPPORTED_CONTENT' }))
+  })
+
   it('emits an empty user message rather than dropping block-less messages', () => {
     const wire = serializeMessages([{ role: 'user', content: [] }])
     expect(wire).toEqual([{ role: 'user', content: '' }])