diff --git a/packages/attachment/attachment-local/src/index.ts b/packages/attachment/attachment-local/src/index.ts
index 516280548c..4fb200345b 100644
--- a/packages/attachment/attachment-local/src/index.ts
+++ b/packages/attachment/attachment-local/src/index.ts
@@ -93,7 +93,11 @@ class SharedRequest<T> {
   wait(signal?: AbortSignal): Promise<T> {
     signal?.throwIfAborted()
     this.waiters += 1
-    if (signal === undefined) return this.promise.finally(() => this.release(false))
+    if (signal === undefined) {
+      return this.promise.finally(() => {
+        this.release(false)
+      })
+    }
     let released = false
     const release = (cancelled: boolean): void => {
       if (released) return
@@ -113,6 +117,8 @@ class SharedRequest<T> {
       }, (error: unknown) => {
         signal.removeEventListener('abort', abort)
         release(false)
+        // CompressionLimiter normalizes task rejections before this handler.
+        // oxlint-disable-next-line typescript/prefer-promise-reject-errors
         reject(error)
       })
     })
diff --git a/packages/attachment/attachment-local/tests/encoding.spec.ts b/packages/attachment/attachment-local/tests/encoding.spec.ts
index d75fc9b4b3..8cd7a60540 100644
--- a/packages/attachment/attachment-local/tests/encoding.spec.ts
+++ b/packages/attachment/attachment-local/tests/encoding.spec.ts
@@ -83,6 +83,7 @@ describe('CompressionLimiter', () => {
 
   it('normalizes a non-Error rejection and releases its slot', async () => {
     const limiter = new CompressionLimiter(1)
+    // oxlint-disable-next-line typescript/prefer-promise-reject-errors -- Native bindings can reject non-Error values.
     const failed = limiter.run(() => Promise.reject('native failure'))
     const next = limiter.run(() => Promise.resolve('next'))
 
diff --git a/packages/attachment/attachment-local/tests/request-image.spec.ts b/packages/attachment/attachment-local/tests/request-image.spec.ts
index e33522c104..726837a242 100644
--- a/packages/attachment/attachment-local/tests/request-image.spec.ts
+++ b/packages/attachment/attachment-local/tests/request-image.spec.ts
@@ -340,7 +340,9 @@ describe('local request-image cache', () => {
     const read = vi.spyOn(attachments, 'readImage').mockImplementation((_ref, signal) => {
       readSignal = signal
       return new Promise((_resolve, reject) => {
-        signal?.addEventListener('abort', () => reject(signal.reason), { once: true })
+        signal?.addEventListener('abort', () => {
+          reject(new Error('request transform aborted', { cause: signal.reason }))
+        }, { once: true })
       })
     })
     const controller = new AbortController()
@@ -349,7 +351,9 @@ describe('local request-image cache', () => {
       { maxPixels: 640_000, maxBytes: 1024 * 1024 },
       controller.signal,
     )
-    await vi.waitFor(() => expect(read).toHaveBeenCalledTimes(1))
+    await vi.waitFor(() => {
+      expect(read).toHaveBeenCalledTimes(1)
+    })
 
     const reason = new Error('cancel only transform waiter')
     controller.abort(reason)
@@ -369,7 +373,9 @@ describe('local request-image cache', () => {
       calls += 1
       if (calls === 1) {
         return new Promise((_resolve, reject) => {
-          signal?.addEventListener('abort', () => reject(signal.reason), { once: true })
+          signal?.addEventListener('abort', () => {
+            reject(new Error('request transform aborted', { cause: signal.reason }))
+          }, { once: true })
         })
       }
       return actualRead(ref, signal)
@@ -377,7 +383,9 @@ describe('local request-image cache', () => {
     const controller = new AbortController()
     const policy = { maxPixels: 640_000, maxBytes: 1024 * 1024 }
     const cancelled = attachments.readImageRequest(master, policy, controller.signal)
-    await vi.waitFor(() => expect(calls).toBe(1))
+    await vi.waitFor(() => {
+      expect(calls).toBe(1)
+    })
 
     controller.abort('cancelled')
     const replacement = attachments.readImageRequest(master, policy)
@@ -389,4 +397,5 @@ describe('local request-image cache', () => {
     await expect(replacement).resolves.toMatchObject({ width: 1130, height: 565 })
     expect(calls).toBe(2)
   })
+
 })
diff --git a/packages/fs/tool-fs/tests/read-image.spec.ts b/packages/fs/tool-fs/tests/read-image.spec.ts
index 3bf86d27f5..03616911b5 100644
--- a/packages/fs/tool-fs/tests/read-image.spec.ts
+++ b/packages/fs/tool-fs/tests/read-image.spec.ts
@@ -251,6 +251,33 @@ describe('read_image_region', () => {
     expect(result.isError).toBe(false)
   })
 
+  it('continues across an earlier session message without the requested image', async () => {
+    const ctx = await setup()
+    const source = await ctx.attachments.saveImage({ data: PNG_3X3, mediaType: 'image/png' })
+    const history = [
+      createUserMessage({
+        content: [{ type: 'text', text: 'before image' }],
+        source: { kind: 'plugin', plugin: 'test' },
+      }),
+      createUserMessage({
+        content: [{ type: 'image', attachment: source.ref }],
+        source: { kind: 'plugin', plugin: 'test' },
+      }),
+    ]
+
+    const result = await call(ctx, 'read_image_region', {
+      attachment_id: source.ref.attachmentId,
+      preview_width: 3,
+      preview_height: 3,
+      x: 0,
+      y: 0,
+      width: 1,
+      height: 1,
+    }, agentOn('vision-model', 'visual', history))
+
+    expect(result.isError).toBe(false)
+  })
+
   it('rejects a missing session, empty id, and invalid coordinate arguments', async () => {
     const ctx = await setup()
     const base = {
diff --git a/packages/interaction/commands/tests/commands.spec.ts b/packages/interaction/commands/tests/commands.spec.ts
index c65fb49bed..85806a1d36 100644
--- a/packages/interaction/commands/tests/commands.spec.ts
+++ b/packages/interaction/commands/tests/commands.spec.ts
@@ -487,9 +487,10 @@ describe('image attachments', () => {
         })
       }),
       validateImageBatch(inputs: readonly unknown[]) {
-        return (AttachmentStore.prototype as unknown as {
+        const validate = AttachmentStore.prototype as unknown as {
           validateImageBatch(this: unknown, batch: readonly unknown[]): void
-        }).validateImageBatch.call(this, inputs)
+        }
+        validate.validateImageBatch.call(this, inputs)
       },
       // The real base-class batch method over this double's limits and members.
       saveImages(inputs: readonly unknown[]) {
diff --git a/packages/llm/llm-deepseek/src/file-store.ts b/packages/llm/llm-deepseek/src/file-store.ts
index ddaefd1eee..0757b42db2 100644
--- a/packages/llm/llm-deepseek/src/file-store.ts
+++ b/packages/llm/llm-deepseek/src/file-store.ts
@@ -50,33 +50,44 @@ function abortReason(signal: AbortSignal): Error {
     : new Error('DeepSeek file upload cancelled with a non-Error reason.', { cause: reason })
 }
 
+function uploadFailure(error: unknown): Error {
+  return error instanceof Error
+    ? error
+    : new Error('DeepSeek file upload failed with a non-Error reason.', { cause: error })
+}
+
 function waitForUpload(operation: SharedUpload, signal: AbortSignal | undefined): Promise<DeepSeekFileReference> {
   signal?.throwIfAborted()
   operation.waiters += 1
   let released = false
-  const release = (cancelled: boolean): void => {
+  const release = (cancelledReason?: Error): void => {
     if (released) return
     released = true
     operation.waiters -= 1
-    if (cancelled && operation.waiters === 0 && !operation.settled) {
-      operation.controller.abort(signal === undefined ? undefined : abortReason(signal))
+    if (cancelledReason !== undefined && operation.waiters === 0 && !operation.settled) {
+      operation.controller.abort(cancelledReason)
     }
   }
-  if (signal === undefined) return operation.promise.finally(() => release(false))
+  if (signal === undefined) {
+    return operation.promise.finally(() => {
+      release()
+    })
+  }
   return new Promise<DeepSeekFileReference>((resolve, reject) => {
     const abort = (): void => {
-      release(true)
-      reject(abortReason(signal))
+      const reason = abortReason(signal)
+      release(reason)
+      reject(reason)
     }
     signal.addEventListener('abort', abort, { once: true })
     void operation.promise.then((value) => {
       signal.removeEventListener('abort', abort)
-      release(false)
+      release()
       resolve(value)
     }, (error: unknown) => {
       signal.removeEventListener('abort', abort)
-      release(false)
-      reject(error)
+      release()
+      reject(uploadFailure(error))
     })
   })
 }
@@ -155,7 +166,7 @@ export class DeepSeekFileStore {
       return value
     }, (error: unknown) => {
       shared.settled = true
-      throw error
+      throw uploadFailure(error)
     })
     this.inflight.set(key, shared)
     void shared.promise.finally(() => {
@@ -168,7 +179,7 @@ export class DeepSeekFileStore {
     version: RequestImageAttachment,
     connection: DeepSeekFileConnection,
     policy: DeepSeekFilePolicy,
-    signal?: AbortSignal,
+    signal: AbortSignal,
   ): Promise<DeepSeekFileReference> {
     if (version.bytes > MAX_CHAT_IMAGE_BYTES) {
       throw new LlmError('DeepSeek chat image exceeds the 32 MiB per-image limit.', 'INVALID_REQUEST')
@@ -186,9 +197,9 @@ export class DeepSeekFileStore {
         mediaType: version.mediaType,
         filename: filename(version),
         expiresAfterSeconds: policy.expiresAfterSeconds,
-        ...signal === undefined ? {} : { signal },
+        signal,
       })
-      if (remote.bytes !== version.data.byteLength || remote.expiresAt === undefined) {
+      if (remote.bytes !== version.data.byteLength) {
         throw new LlmError('DeepSeek Files API upload response does not match the submitted image.', 'INVALID_RESPONSE')
       }
       return {
diff --git a/packages/llm/llm-deepseek/src/files-api.ts b/packages/llm/llm-deepseek/src/files-api.ts
index f19823100e..cc998b2e7e 100644
--- a/packages/llm/llm-deepseek/src/files-api.ts
+++ b/packages/llm/llm-deepseek/src/files-api.ts
@@ -143,7 +143,6 @@ export class DeepSeekFilesClient {
     let response: Response
     try {
       const headers = new Headers(attributionHeaders())
-      for (const [name, value] of new Headers(init.headers)) headers.set(name, value)
       headers.set('authorization', `Bearer ${this.apiKey}`)
       response = await this.fetchImpl(`${this.baseURL}${path}`, {
         ...init,
@@ -180,7 +179,7 @@ export class DeepSeekFilesClient {
     filename: string
     expiresAfterSeconds: number
     signal?: AbortSignal
-  }): Promise<DeepSeekFileObject> {
+  }): Promise<DeepSeekFileObject & { expiresAt: number }> {
     if (input.data.byteLength > MAX_FILE_UPLOAD_BYTES) {
       throw new LlmError('DeepSeek Files API upload exceeds 128 MiB.', 'INVALID_REQUEST')
     }
@@ -197,7 +196,7 @@ export class DeepSeekFilesClient {
     const response = await this.request('/files', { method: 'POST', body: form }, input.signal)
     const file = parseFileObject(await response.json(), 'upload')
     if (file.expiresAt === undefined) throw invalidResponse('upload')
-    return file
+    return { ...file, expiresAt: file.expiresAt }
   }
 
   /**
diff --git a/packages/llm/llm-deepseek/src/serialize.ts b/packages/llm/llm-deepseek/src/serialize.ts
index a65c9750c3..b998b23a8b 100644
--- a/packages/llm/llm-deepseek/src/serialize.ts
+++ b/packages/llm/llm-deepseek/src/serialize.ts
@@ -317,7 +317,7 @@ export async function serializeMessagesWithImages(
       wire.push({
         role: 'tool',
         tool_call_id: result.toolCallId,
-        content: text || (fileParts.length > 0 ? '(see attached image)' : '(no output)'),
+        content: text || '(no output)',
       })
       pendingToolImages.push(...fileParts)
     }
diff --git a/packages/llm/llm-deepseek/tests/adapter.spec.ts b/packages/llm/llm-deepseek/tests/adapter.spec.ts
index 731df2eb0f..2663c4cd78 100644
--- a/packages/llm/llm-deepseek/tests/adapter.spec.ts
+++ b/packages/llm/llm-deepseek/tests/adapter.spec.ts
@@ -176,6 +176,7 @@ describe('DeepSeekAdapter against a mock server', () => {
     await drain(adapter.stream({
       provider: 'deepseek-official',
       model: 'deepseek-v4-flash-vision-exp',
+      tools: [{ name: 'read_image_region', description: 'crop', parameters: { type: 'object' } }],
       messages: [createUserMessage({
         content: [
           { type: 'text', text: 'describe ' },
@@ -191,7 +192,7 @@ describe('DeepSeekAdapter against a mock server', () => {
         role: 'user',
         content: [
           { type: 'text', text: 'describe ' },
-          { type: 'text', text: expect.stringContaining(`Image ${imageRef.attachmentId}`) as string },
+          { type: 'text', text: expect.stringContaining('Call read_image_region') as string },
           { type: 'file', file_id: 'file-api-1' },
         ],
       }],
@@ -1499,6 +1500,23 @@ describe('plugin registration and config', () => {
       .toThrow(/maxTokens must be a positive integer/)
   })
 
+  it('rejects image request limits on a text-only catalog model', () => {
+    expect(() => resolveAdapterOptions({
+      models: [{ id: 'text-only', inputModalities: ['text'], imagePixelBudget: 1 }],
+    })).toThrow(/text-only catalog model .* cannot declare image request limits/)
+  })
+
+  it.each([
+    ['imagePixelBudget', 0, /imagePixelBudget must be a positive safe integer/],
+    ['imagePixelBudget', Number.MAX_SAFE_INTEGER + 1, /imagePixelBudget must be a positive safe integer/],
+    ['imageMaxBytes', 0, /imageMaxBytes must be a positive safe integer/],
+    ['imageMaxBytes', 1.5, /imageMaxBytes must be a positive safe integer/],
+  ] as const)('rejects per-model %s=%s', (field, value, message) => {
+    expect(() => resolveAdapterOptions({
+      models: [{ id: 'vision', inputModalities: ['image'], [field]: value }],
+    })).toThrow(message)
+  })
+
   it('prefers a model\'s own output cap over the profile default', async () => {
     // The profile default stays what an unlisted or uncapped model resolves
     // to, so adding a per-model cap changes one model rather than the route.
@@ -1569,6 +1587,23 @@ describe('plugin registration and config', () => {
     })).toThrow(/imageOffloadCountQuantum must not exceed maxImagesPerRequest/)
   })
 
+  it.each([
+    ['maxImagesPerRequest', 0, /maxImagesPerRequest must be a positive safe integer/],
+    ['maxImagesPerRequest', 1.5, /maxImagesPerRequest must be a positive safe integer/],
+    ['imageOffloadByteQuantum', 0, /imageOffloadByteQuantum must be a positive safe integer/],
+    ['imageOffloadByteQuantum', Number.MAX_SAFE_INTEGER + 1, /imageOffloadByteQuantum must be a positive safe integer/],
+    ['imageOffloadCountQuantum', 0, /imageOffloadCountQuantum must be a positive safe integer/],
+    ['imageOffloadCountQuantum', 1.5, /imageOffloadCountQuantum must be a positive safe integer/],
+    ['fileExpiresAfterSeconds', 3_599, /fileExpiresAfterSeconds must be an integer from 3600 through 2592000/],
+    ['fileExpiresAfterSeconds', 2_592_001, /fileExpiresAfterSeconds must be an integer from 3600 through 2592000/],
+    ['fileRefreshMarginSeconds', -1, /fileRefreshMarginSeconds must be a non-negative integer/],
+    ['fileRefreshMarginSeconds', 604_800, /fileRefreshMarginSeconds must be a non-negative integer/],
+    ['fileQuotaCleanupBatch', 0, /fileQuotaCleanupBatch must be an integer from 1 through 1000/],
+    ['fileQuotaCleanupBatch', 1_001, /fileQuotaCleanupBatch must be an integer from 1 through 1000/],
+  ] as const)('rejects %s=%s', (field, value, message) => {
+    expect(() => resolveAdapterOptions({ [field]: value })).toThrow(message)
+  })
+
   it.each([0, 1.5, Number.MAX_SAFE_INTEGER + 1])(
     'rejects invalid request file bound %s',
     async (maxRequestFilesBytes) => {
diff --git a/packages/llm/llm-deepseek/tests/file-store.spec.ts b/packages/llm/llm-deepseek/tests/file-store.spec.ts
index 6d9e940786..069ff47c9d 100644
--- a/packages/llm/llm-deepseek/tests/file-store.spec.ts
+++ b/packages/llm/llm-deepseek/tests/file-store.spec.ts
@@ -4,8 +4,9 @@ import { join } from 'node:path'
 import { describe, expect, it, vi } from 'vitest'
 import { AttachmentId, ImageVariantId } from '@deepseek-ai/dsh-attachment'
 import type { ImageAttachmentRef, RequestImageAttachment } from '@deepseek-ai/dsh-attachment'
-import { DeepSeekFileStore } from '../src/file-store.ts'
-import { DeepSeekUploadIndex } from '../src/upload-index.ts'
+import { DeepSeekFileStore, MAX_CHAT_IMAGE_BYTES } from '../src/file-store.ts'
+import { DeepSeekFileId } from '../src/file-id.ts'
+import { deepSeekFileScope, DeepSeekUploadIndex } from '../src/upload-index.ts'
 
 const REF: ImageAttachmentRef = {
   attachmentId: AttachmentId(`sha256:${'a'.repeat(64)}`),
@@ -90,7 +91,9 @@ describe('DeepSeekFileStore', () => {
       uploadSignal = init?.signal ?? undefined
       return new Promise<Response>((resolve, reject) => {
         complete = resolve
-        uploadSignal?.addEventListener('abort', () => reject(uploadSignal?.reason), { once: true })
+        uploadSignal?.addEventListener('abort', () => {
+          reject(new Error('upload aborted', { cause: uploadSignal?.reason }))
+        }, { once: true })
       })
     }) as typeof fetch
     const store = new DeepSeekFileStore({ index, now: () => NOW, fetch: fetchImpl })
@@ -98,7 +101,9 @@ describe('DeepSeekFileStore', () => {
 
     const cancelled = store.ensureUploaded(VERSION, CONNECTION, POLICY, controller.signal)
     const completed = store.ensureUploaded(VERSION, CONNECTION, POLICY)
-    await vi.waitFor(() => expect(fetchImpl).toHaveBeenCalledTimes(1))
+    await vi.waitFor(() => {
+      expect(fetchImpl).toHaveBeenCalledTimes(1)
+    })
     const reason = new Error('cancel one upload waiter')
     controller.abort(reason)
 
@@ -123,13 +128,17 @@ describe('DeepSeekFileStore', () => {
     const fetchImpl = vi.fn((_url: string | URL | Request, init?: RequestInit) => {
       uploadSignal = init?.signal ?? undefined
       return new Promise<Response>((_resolve, reject) => {
-        uploadSignal?.addEventListener('abort', () => reject(uploadSignal?.reason), { once: true })
+        uploadSignal?.addEventListener('abort', () => {
+          reject(new Error('upload aborted', { cause: uploadSignal?.reason }))
+        }, { once: true })
       })
     }) as typeof fetch
     const store = new DeepSeekFileStore({ index, now: () => NOW, fetch: fetchImpl })
     const controller = new AbortController()
     const upload = store.ensureUploaded(VERSION, CONNECTION, POLICY, controller.signal)
-    await vi.waitFor(() => expect(fetchImpl).toHaveBeenCalledTimes(1))
+    await vi.waitFor(() => {
+      expect(fetchImpl).toHaveBeenCalledTimes(1)
+    })
 
     const reason = new Error('cancel only upload waiter')
     controller.abort(reason)
@@ -138,6 +147,79 @@ describe('DeepSeekFileStore', () => {
     expect(uploadSignal?.reason).toBe(reason)
   })
 
+  it('normalizes a non-Error cancellation reason', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
+    const fetchImpl = vi.fn((_url: string | URL | Request, init?: RequestInit) => (
+      new Promise<Response>((_resolve, reject) => {
+        init?.signal?.addEventListener('abort', () => {
+          reject(new Error('upload aborted', { cause: init.signal?.reason }))
+        }, { once: true })
+      })
+    )) as typeof fetch
+    const store = new DeepSeekFileStore({
+      index: new DeepSeekUploadIndex(join(dir, 'index.json')),
+      now: () => NOW,
+      fetch: fetchImpl,
+    })
+    const controller = new AbortController()
+    const upload = store.ensureUploaded(VERSION, CONNECTION, POLICY, controller.signal)
+    await vi.waitFor(() => {
+      expect(fetchImpl).toHaveBeenCalledOnce()
+    })
+    controller.abort('cancelled')
+
+    await expect(upload).rejects.toMatchObject({
+      message: 'DeepSeek file upload cancelled with a non-Error reason.',
+      cause: 'cancelled',
+    })
+  })
+
+  it('starts a fresh upload while the cancelled transport is settling', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
+    let requests = 0
+    const fetchImpl = vi.fn((_url: string | URL | Request, init?: RequestInit) => {
+      requests += 1
+      if (requests === 1) {
+        return new Promise<Response>((_resolve, reject) => {
+          init?.signal?.addEventListener('abort', () => {
+            queueMicrotask(() => {
+              reject(new Error('upload aborted', { cause: init.signal?.reason }))
+            })
+          }, { once: true })
+        })
+      }
+      return Promise.resolve(new Response(JSON.stringify({
+        id: 'file-api-retry', object: 'file', bytes: 3, created_at: NOW / 1_000,
+        filename: 'dsh-retry.png', purpose: 'user_data',
+        expires_at: NOW / 1_000 + POLICY.expiresAfterSeconds,
+      }), { status: 200 }))
+    }) as typeof fetch
+    const store = new DeepSeekFileStore({
+      index: new DeepSeekUploadIndex(join(dir, 'index.json')),
+      now: () => NOW,
+      fetch: fetchImpl,
+    })
+    const controller = new AbortController()
+    const cancelled = store.ensureUploaded(VERSION, CONNECTION, POLICY, controller.signal)
+    await vi.waitFor(() => {
+      expect(fetchImpl).toHaveBeenCalledOnce()
+    })
+    controller.abort(new Error('cancel first'))
+    const retried = store.ensureUploaded(VERSION, CONNECTION, POLICY)
+
+    await expect(cancelled).rejects.toThrow('cancel first')
+    await expect(retried).resolves.toMatchObject({ record: { fileId: 'file-api-retry' } })
+  })
+
+  it('rejects a request version above the chat per-image limit before transport', async () => {
+    const fetchImpl = vi.fn() as typeof fetch
+    const store = new DeepSeekFileStore({ now: () => NOW, fetch: fetchImpl })
+    const oversized = { ...VERSION, bytes: MAX_CHAT_IMAGE_BYTES + 1 }
+    await expect(store.ensureUploaded(oversized, CONNECTION, POLICY))
+      .rejects.toMatchObject({ code: 'INVALID_REQUEST' })
+    expect(fetchImpl).not.toHaveBeenCalled()
+  })
+
   it('does not persist an upload whose response is missing and retries on the next request', async () => {
     const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
     const index = new DeepSeekUploadIndex(join(dir, 'index.json'))
@@ -158,6 +240,55 @@ describe('DeepSeekFileStore', () => {
       .resolves.toMatchObject({ record: { fileId: 'file-api-1' }, uploaded: true })
   })
 
+  it('rejects an upload response whose byte count differs from the request version', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
+    const fetchImpl = vi.fn(() => Promise.resolve(new Response(JSON.stringify({
+      id: 'file-api-wrong-size', object: 'file', bytes: 2, created_at: NOW / 1_000,
+      filename: 'dsh-wrong.png', purpose: 'user_data',
+      expires_at: NOW / 1_000 + POLICY.expiresAfterSeconds,
+    }), { status: 200 }))) as typeof fetch
+    const store = new DeepSeekFileStore({
+      index: new DeepSeekUploadIndex(join(dir, 'index.json')),
+      now: () => NOW,
+      fetch: fetchImpl,
+    })
+    await expect(store.ensureUploaded(VERSION, CONNECTION, POLICY))
+      .rejects.toMatchObject({ code: 'INVALID_RESPONSE' })
+  })
+
+  it.each([
+    ['image/jpeg', 'jpeg'],
+    ['image/webp', 'webp'],
+    ['image/gif', 'gif'],
+  ] as const)('uses the %s filename extension for uploads', async (mediaType, extension) => {
+    const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
+    const remote = uploadFetch()
+    const store = new DeepSeekFileStore({
+      index: new DeepSeekUploadIndex(join(dir, `${extension}.json`)),
+      now: () => NOW,
+      fetch: remote.fetchImpl,
+    })
+    await store.ensureUploaded({ ...VERSION, mediaType }, CONNECTION, POLICY)
+    const form = vi.mocked(remote.fetchImpl).mock.calls[0]?.[1]?.body
+    expect(form).toBeInstanceOf(FormData)
+    const file = (form as FormData).get('file')
+    expect(file).toBeInstanceOf(File)
+    if (!(file instanceof File)) throw new Error('expected multipart file')
+    expect(file.name).toMatch(new RegExp(`\\.${extension}$`, 'u'))
+  })
+
+  it('normalizes a non-Error failure from the durable upload index', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
+    const index = new DeepSeekUploadIndex(join(dir, 'index.json'))
+    vi.spyOn(index, 'get').mockRejectedValue('index unavailable')
+    const store = new DeepSeekFileStore({ index, now: () => NOW, fetch: vi.fn() as typeof fetch })
+
+    await expect(store.ensureUploaded(VERSION, CONNECTION, POLICY)).rejects.toMatchObject({
+      message: 'DeepSeek file upload failed with a non-Error reason.',
+      cause: 'index unavailable',
+    })
+  })
+
   it('reuses local expires_at above the refresh margin and uploads again at the margin', async () => {
     const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
     const index = new DeepSeekUploadIndex(join(dir, 'index.json'))
@@ -190,6 +321,101 @@ describe('DeepSeekFileStore', () => {
     expect(remote.fetchImpl).toHaveBeenCalledTimes(2)
   })
 
+  it('removes a losing upload and keeps the winning durable mapping when duplicate cleanup fails', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
+    const index = new DeepSeekUploadIndex(join(dir, 'index.json'))
+    vi.spyOn(index, 'commit').mockResolvedValue({
+      accepted: false,
+      record: {
+        scope: deepSeekFileScope(CONNECTION.baseURL, CONNECTION.apiKey),
+        masterAttachmentId: VERSION.master.attachmentId,
+        variantId: VERSION.variantId,
+        fileId: DeepSeekFileId('file-api-winner'),
+        bytes: 3,
+        createdAt: NOW,
+        expiresAt: NOW + POLICY.expiresAfterSeconds * 1_000,
+      },
+    })
+    const remote = uploadFetch()
+    const fetchImpl = vi.fn((url: string | URL | Request, init?: RequestInit) => {
+      if (init?.method === 'DELETE') return Promise.resolve(new Response('failed', { status: 500 }))
+      return remote.fetchImpl(url, init)
+    }) as typeof fetch
+    const store = new DeepSeekFileStore({ index, now: () => NOW, fetch: fetchImpl })
+
+    await expect(store.ensureUploaded(VERSION, CONNECTION, POLICY)).resolves.toMatchObject({
+      record: { fileId: 'file-api-winner' },
+      uploaded: false,
+    })
+    expect(fetchImpl).toHaveBeenCalledTimes(2)
+  })
+
+  it('reclaims one owned file after quota rejection and retries the upload once', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
+    let uploads = 0
+    const fetchImpl = vi.fn((input: string | URL | Request, init?: RequestInit) => {
+      if (init?.method === 'POST') {
+        uploads += 1
+        if (uploads === 1) return Promise.resolve(new Response(JSON.stringify({
+          error: { message: 'stored file quota exceeded', code: 'file_quota' },
+        }), { status: 400 }))
+        return Promise.resolve(new Response(JSON.stringify({
+          id: 'file-api-recovered', object: 'file', bytes: 3, created_at: NOW / 1_000,
+          filename: 'dsh-recovered.png', purpose: 'user_data',
+          expires_at: NOW / 1_000 + POLICY.expiresAfterSeconds,
+        }), { status: 200 }))
+      }
+      if (init?.method === 'DELETE') {
+        return Promise.resolve(new Response(JSON.stringify({
+          id: 'file-api-old', object: 'file', deleted: true,
+        }), { status: 200 }))
+      }
+      expect(new URL(requestUrl(input)).pathname).toBe('/files')
+      return Promise.resolve(new Response(JSON.stringify({
+        object: 'list',
+        data: [{
+          id: 'file-api-old', object: 'file', bytes: 3, created_at: NOW / 1_000,
+          filename: 'dsh-old.png', purpose: 'user_data',
+        }],
+        first_id: 'file-api-old', last_id: 'file-api-old', has_more: false,
+      }), { status: 200 }))
+    }) as typeof fetch
+    const store = new DeepSeekFileStore({
+      index: new DeepSeekUploadIndex(join(dir, 'index.json')),
+      now: () => NOW,
+      fetch: fetchImpl,
+    })
+
+    await expect(store.ensureUploaded(VERSION, CONNECTION, POLICY)).resolves.toMatchObject({
+      record: { fileId: 'file-api-recovered' }, uploaded: true,
+    })
+    expect(uploads).toBe(2)
+  })
+
+  it('preserves a quota error when no harness-owned file can be reclaimed', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
+    const fetchImpl = vi.fn((_input: string | URL | Request, init?: RequestInit) => {
+      if (init?.method === 'POST') return Promise.resolve(new Response(JSON.stringify({
+        error: { message: 'file count quota exceeded', code: 'file_quota' },
+      }), { status: 400 }))
+      return Promise.resolve(new Response(JSON.stringify({
+        object: 'list',
+        data: [{
+          id: 'file-api-foreign', object: 'file', bytes: 3, created_at: NOW / 1_000,
+          filename: 'foreign.png', purpose: 'user_data',
+        }],
+        has_more: false,
+      }), { status: 200 }))
+    }) as typeof fetch
+    const store = new DeepSeekFileStore({
+      index: new DeepSeekUploadIndex(join(dir, 'index.json')),
+      now: () => NOW,
+      fetch: fetchImpl,
+    })
+
+    await expect(store.ensureUploaded(VERSION, CONNECTION, POLICY)).rejects.toMatchObject({ code: 'FILES_API' })
+  })
+
   it('finishes pagination before deleting cursor files during quota recovery', async () => {
     const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
     const deleted = new Set<string>()
@@ -227,4 +453,44 @@ describe('DeepSeekFileStore', () => {
     await expect(store.reclaimOldestOwned(CONNECTION, 2)).resolves.toBe(2)
     expect([...deleted]).toEqual(['file-api-oldest', 'file-api-next'])
   })
+
+  it('stops pagination when a page omits or repeats its cursor', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
+    for (const mode of ['missing', 'repeated'] as const) {
+      let page = 0
+      const fetchImpl = vi.fn((input: string | URL | Request, init?: RequestInit) => {
+        if (init?.method === 'DELETE') {
+          const id = requestUrl(input).split('/').at(-1)
+          return Promise.resolve(new Response(JSON.stringify({ id, object: 'file', deleted: true }), { status: 200 }))
+        }
+        page += 1
+        const lastId = mode === 'missing' ? undefined : 'file-api-same'
+        return Promise.resolve(new Response(JSON.stringify({
+          object: 'list', data: [], has_more: true,
+          ...lastId === undefined ? {} : { last_id: lastId },
+        }), { status: 200 }))
+      }) as typeof fetch
+      const store = new DeepSeekFileStore({
+        index: new DeepSeekUploadIndex(join(dir, `${mode}.json`)),
+        now: () => NOW,
+        fetch: fetchImpl,
+      })
+      await expect(store.reclaimOldestOwned(CONNECTION, 1)).resolves.toBe(0)
+      expect(page).toBe(mode === 'missing' ? 1 : 2)
+    }
+  })
+
+  it('releases every batch and clears the scoped upload index', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'dsh-file-store-'))
+    const index = new DeepSeekUploadIndex(join(dir, 'index.json'))
+    const store = new DeepSeekFileStore({ index, now: () => NOW, fetch: vi.fn() as typeof fetch })
+    const reclaim = vi.spyOn(store, 'reclaimOldestOwned')
+      .mockResolvedValueOnce(1_000)
+      .mockResolvedValueOnce(2)
+    const clear = vi.spyOn(index, 'clear')
+
+    await expect(store.releaseAll(CONNECTION)).resolves.toBe(1_002)
+    expect(reclaim).toHaveBeenCalledTimes(2)
+    expect(clear).toHaveBeenCalledOnce()
+  })
 })
diff --git a/packages/llm/llm-deepseek/tests/files-api.spec.ts b/packages/llm/llm-deepseek/tests/files-api.spec.ts
index 466c9be83b..e6a1aa59ea 100644
--- a/packages/llm/llm-deepseek/tests/files-api.spec.ts
+++ b/packages/llm/llm-deepseek/tests/files-api.spec.ts
@@ -119,7 +119,7 @@ describe('DeepSeekFilesClient', () => {
     const client = new DeepSeekFilesClient({
       baseURL: 'https://api.deepseek.com',
       apiKey: 'key',
-      fetch: vi.fn(() => Promise.resolve(new Response('not-json', { status }))) as typeof fetch,
+      fetch: vi.fn(() => Promise.resolve(new Response('not-json', { status }))),
     })
     await expect(client.retrieve(DeepSeekFileId('missing'))).rejects.toMatchObject({
       name: 'DeepSeekFilesError',
@@ -139,7 +139,7 @@ describe('DeepSeekFilesClient', () => {
     const client = new DeepSeekFilesClient({
       baseURL: 'https://api.deepseek.com',
       apiKey: 'key',
-      fetch: vi.fn(() => Promise.resolve(new Response(JSON.stringify(body), { status: 400 }))) as typeof fetch,
+      fetch: vi.fn(() => Promise.resolve(new Response(JSON.stringify(body), { status: 400 }))),
     })
     const error = await client.retrieve(DeepSeekFileId('missing')).catch((caught: unknown) => caught)
     expect(error).toBeInstanceOf(DeepSeekFilesError)
@@ -151,7 +151,7 @@ describe('DeepSeekFilesClient', () => {
     const client = new DeepSeekFilesClient({
       baseURL: 'https://api.deepseek.com',
       apiKey: 'key',
-      fetch: vi.fn(() => Promise.reject(transport)) as typeof fetch,
+      fetch: vi.fn(() => Promise.reject(transport)),
     })
     await expect(client.retrieve(DeepSeekFileId('one'))).rejects.toMatchObject({
       code: 'TRANSPORT',
@@ -183,7 +183,7 @@ describe('DeepSeekFilesClient', () => {
     const client = new DeepSeekFilesClient({
       baseURL: 'https://api.deepseek.com',
       apiKey: 'key',
-      fetch: vi.fn(() => Promise.resolve(new Response(JSON.stringify(body), { status: 200 }))) as typeof fetch,
+      fetch: vi.fn(() => Promise.resolve(new Response(JSON.stringify(body), { status: 200 }))),
     })
     await expect(client.retrieve(DeepSeekFileId('one'))).rejects.toMatchObject({ code: 'INVALID_RESPONSE' })
   })
@@ -224,7 +224,7 @@ describe('DeepSeekFilesClient', () => {
     const client = new DeepSeekFilesClient({
       baseURL: 'https://api.deepseek.com',
       apiKey: 'key',
-      fetch: vi.fn(() => Promise.resolve(new Response(JSON.stringify(body), { status: 200 }))) as typeof fetch,
+      fetch: vi.fn(() => Promise.resolve(new Response(JSON.stringify(body), { status: 200 }))),
     })
     await expect(client.list()).rejects.toMatchObject({ code: 'INVALID_RESPONSE' })
   })
@@ -253,7 +253,7 @@ describe('DeepSeekFilesClient', () => {
     const client = new DeepSeekFilesClient({
       baseURL: 'https://api.deepseek.com',
       apiKey: 'key',
-      fetch: vi.fn(() => Promise.resolve(new Response(JSON.stringify(body), { status: 200 }))) as typeof fetch,
+      fetch: vi.fn(() => Promise.resolve(new Response(JSON.stringify(body), { status: 200 }))),
     })
     await expect(client.delete(DeepSeekFileId('file-api-one'))).rejects.toMatchObject({ code: 'INVALID_RESPONSE' })
   })
diff --git a/packages/llm/llm-deepseek/tests/serialize.spec.ts b/packages/llm/llm-deepseek/tests/serialize.spec.ts
index 8e04b9b3b0..06af757c9a 100644
--- a/packages/llm/llm-deepseek/tests/serialize.spec.ts
+++ b/packages/llm/llm-deepseek/tests/serialize.spec.ts
@@ -399,6 +399,14 @@ describe('image serialization', () => {
     })
   })
 
+  it('rejects an image whose prepared request version is absent', async () => {
+    const ref = imageRef()
+    await expect(serializeMessagesWithImages([createUserMessage({
+      content: [{ type: 'image', attachment: ref }],
+      source: { kind: 'plugin', plugin: 'test' },
+    })], imageOptions([]))).rejects.toMatchObject({ code: 'INVALID_REQUEST' })
+  })
+
   it('keeps tool content textual and groups consecutive tool-result images afterward', async () => {
     const messages = [
       createUserMessage({
@@ -561,6 +569,17 @@ describe('image serialization', () => {
     expect(resolveFileId.mock.calls[0]?.[0]).toMatchObject({ master: { mediaType: 'image/jpeg' } })
   })
 
+  it('rejects an unprepared image while computing exact request bytes', async () => {
+    const ref = imageRef()
+    await expect(serializeRequestWithImages(request({
+      model: 'deepseek-v4-flash-vision-exp',
+      messages: [createUserMessage({
+        content: [{ type: 'image', attachment: ref }],
+        source: { kind: 'plugin', plugin: 'test' },
+      })],
+    }), imageOptions([]))).rejects.toMatchObject({ code: 'INVALID_REQUEST' })
+  })
+
   it.each(['system', 'assistant'] as const)('rejects an image in %s history before reading attachments', async (role) => {
     const resolveFileId = vi.fn()
     await expect(serializeMessagesWithImages([createMessage({
diff --git a/packages/llm/llm-pi-ai/tests/config.spec.ts b/packages/llm/llm-pi-ai/tests/config.spec.ts
index 55444228de..61a2535a9d 100644
--- a/packages/llm/llm-pi-ai/tests/config.spec.ts
+++ b/packages/llm/llm-pi-ai/tests/config.spec.ts
@@ -64,3 +64,26 @@ describe('modality schema boundary', () => {
     expect(absent.providers['acme-gateway']?.defaultInput).toEqual(['text'])
   })
 })
+
+describe('request image policy bounds', () => {
+  it.each([
+    ['requestImagePixelBudget', 0, /requestImagePixelBudget must be a positive safe integer/],
+    ['requestImagePixelBudget', Number.MAX_SAFE_INTEGER + 1, /requestImagePixelBudget must be a positive safe integer/],
+    ['requestImageMaxBytes', 0, /requestImageMaxBytes must be a positive safe integer/],
+    ['requestImageMaxBytes', 1.5, /requestImageMaxBytes must be a positive safe integer/],
+  ] as const)('rejects %s=%s at service resolution', (field, value, message) => {
+    const programmatic = {
+      providers: {
+        'acme-gateway': {
+          api: 'openai-completions',
+          baseURL: 'https://acme.test',
+          models: [{ id: 'm' }],
+          [field]: value,
+        },
+      },
+    } as unknown as Config
+    expect(() => {
+      assertServiceable(programmatic)
+    }).toThrow(message)
+  })
+})
diff --git a/packages/llm/llm-pi-ai/tests/context.spec.ts b/packages/llm/llm-pi-ai/tests/context.spec.ts
index a0fb671c95..8a3f7bd084 100644
--- a/packages/llm/llm-pi-ai/tests/context.spec.ts
+++ b/packages/llm/llm-pi-ai/tests/context.spec.ts
@@ -428,4 +428,14 @@ describe('pi-ai request context conversion', () => {
       history('assistant', [{ type: 'image', attachment: ref }]),
     )).toThrow(/assistant image output/)
   })
+
+  it('rejects an attachment service that omits a requested image version', async () => {
+    const store = {
+      readImageRequests: vi.fn(() => Promise.resolve([])),
+    } as unknown as AttachmentStore
+    await expect(toPiContext(
+      request([user([{ type: 'image', attachment: ref }])]),
+      store,
+    )).rejects.toMatchObject({ code: 'INVALID_REQUEST' })
+  })
 })
diff --git a/packages/llm/llm/src/content.ts b/packages/llm/llm/src/content.ts
index 73a2aee889..72e452e005 100644
--- a/packages/llm/llm/src/content.ts
+++ b/packages/llm/llm/src/content.ts
@@ -74,7 +74,9 @@ function collectImageLengths(
 ): void {
   for (const block of blocks) {
     if (block.type === 'image') {
-      const bytes = policy.byteLength?.(block.attachment) ?? block.attachment.bytes
+      const bytes = policy.byteLength === undefined
+        ? block.attachment.bytes
+        : policy.byteLength(block.attachment)
       lengths.push(policy.representation === 'base64' ? base64Length(bytes) : bytes)
     } else if (block.type === 'tool-result') {
       collectImageLengths(block.content, lengths, policy)
diff --git a/packages/llm/llm/tests/content.spec.ts b/packages/llm/llm/tests/content.spec.ts
index d1b02fa011..6a0eb02c63 100644
--- a/packages/llm/llm/tests/content.spec.ts
+++ b/packages/llm/llm/tests/content.spec.ts
@@ -1,6 +1,13 @@
 import { describe, expect, it } from 'vitest'
 import { AttachmentId } from '@deepseek-ai/dsh-attachment'
-import { CallId, createUserMessage, OFFLOADED_IMAGE_TEXT, offloadRequestImages, offloadRequestImagesWithPolicy } from '../src/index.ts'
+import {
+  CallId,
+  createUserMessage,
+  OFFLOADED_IMAGE_TEXT,
+  offloadRequestImages,
+  offloadRequestImagesWithPolicy,
+  projectImagesForTextModel,
+} from '../src/index.ts'
 import type { ContentBlock } from '../src/index.ts'
 
 const source = { kind: 'plugin' as const, plugin: 'test' }
@@ -19,6 +26,11 @@ function image(bytes: number): ContentBlock {
 }
 
 describe('offloadRequestImages', () => {
+  it('preserves every image when no payload bound is configured', () => {
+    const messages = [createUserMessage({ content: [image(300)], source })]
+    expect(offloadRequestImages(messages, undefined)).toBe(messages)
+  })
+
   it('preserves the original request when its base64 payload fits exactly', () => {
     const messages = [createUserMessage({ content: [image(3), image(3)], source })]
     expect(offloadRequestImages(messages, 8)).toBe(messages)
@@ -116,4 +128,58 @@ describe('offloadRequestImagesWithPolicy', () => {
     expect(projected[0]?.content.filter(block => block.type === 'text')).toHaveLength(20)
     expect(projected[0]?.content.filter(block => block.type === 'image')).toHaveLength(581)
   })
+
+  it('uses route-owned request byte lengths when supplied', () => {
+    const messages = [createUserMessage({ content: [image(100), image(100)], source })]
+    const projected = offloadRequestImagesWithPolicy(messages, {
+      representation: 'raw',
+      maxBytes: 3,
+      byteLength: () => 2,
+    })
+    expect(projected[0]?.content).toEqual([
+      { type: 'text', text: OFFLOADED_IMAGE_TEXT },
+      image(100),
+    ])
+  })
+})
+
+describe('projectImagesForTextModel', () => {
+  it('returns image-free history unchanged', () => {
+    const messages = [createUserMessage({ content: [{ type: 'text', text: 'plain' }], source })]
+    expect(projectImagesForTextModel(messages)).toBe(messages)
+  })
+
+  it('replaces direct and nested images while retaining unaffected messages and blocks', () => {
+    const plain = createUserMessage({ content: [{ type: 'text', text: 'plain' }], source })
+    const nested = {
+      type: 'tool-result' as const,
+      toolCallId: CallId('nested-image'),
+      content: [{ type: 'text' as const, text: 'before' }, image(3), { type: 'text' as const, text: 'after' }],
+    }
+    const unchangedNested = {
+      type: 'tool-result' as const,
+      toolCallId: CallId('text-only'),
+      content: [{ type: 'text' as const, text: 'unchanged' }],
+    }
+    const visual = createUserMessage({
+      content: [{ type: 'text', text: 'lead' }, image(3), unchangedNested, nested],
+      source,
+    })
+
+    const projected = projectImagesForTextModel([plain, visual])
+    expect(projected[0]).toBe(plain)
+    expect(projected[1]?.content).toEqual([
+      { type: 'text', text: 'lead' },
+      { type: 'text', text: '[image omitted because this model accepts text only; attachment sha256:aaaaaaaa]' },
+      unchangedNested,
+      {
+        ...nested,
+        content: [
+          { type: 'text', text: 'before' },
+          { type: 'text', text: '[image omitted because this model accepts text only; attachment sha256:aaaaaaaa]' },
+          { type: 'text', text: 'after' },
+        ],
+      },
+    ])
+  })
 })
diff --git a/packages/llm/llm/tests/service.spec.ts b/packages/llm/llm/tests/service.spec.ts
index b2e5399964..4c624fa862 100644
--- a/packages/llm/llm/tests/service.spec.ts
+++ b/packages/llm/llm/tests/service.spec.ts
@@ -986,6 +986,18 @@ describe('LlmRuntime', () => {
       type: 'text',
       text: '[image omitted because this model accepts text only; attachment sha256:aaaaaaaa]',
     }])
+
+    const frozen = Object.freeze({
+      provider: 'route',
+      model: 'text-only',
+      messages: [createUserMessage({
+        content: [{ type: 'image', attachment }],
+        source: { kind: 'plugin' as const, plugin: 'test' },
+      })],
+    })
+    await collect(ctx.llm.stream(frozen))
+    expect(Object.isFrozen(seen[1])).toBe(true)
+    expect(Object.isFrozen(seen[1]?.messages)).toBe(true)
   })
 
   it('passes cancellation through exact-model resolution', async () => {