feat(core): add post-step request recovery (PR3 phase 1)

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

@@ -2,7 +2,7 @@ import { createServer } from 'node:http'
 import type { IncomingMessage, Server, ServerResponse } from 'node:http'
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
-import LlmService, { LlmError, userAgent } from '@deepseek-ai/dsh-llm'
+import LlmService, { CONTEXT_WINDOW_EXCEEDED_CODE, LlmError, userAgent } from '@deepseek-ai/dsh-llm'
 import * as LlmDeepSeek from '@deepseek-ai/dsh-llm-deepseek'
 import { DeepSeekAdapter, httpErrorCode } from '@deepseek-ai/dsh-llm-deepseek'
 import { assemble } from './assemble.ts'
@@ -173,6 +173,32 @@ describe('DeepSeekAdapter against a mock server', () => {
     ).resolves.toBe(status)
   })
 
+  it('classifies a thrown HTTP context-window rejection with the canonical code', async () => {
+    const server = await mockServer([{
+      kind: 'http-error',
+      status: 400,
+      body: JSON.stringify({
+        error: {
+          message: 'This model maximum context length is 128000 tokens; your input exceeds that limit.',
+          type: 'invalid_request_error',
+          code: 'context_length_exceeded',
+        },
+      }),
+    }])
+    const ctx = await harness(server.url)
+    const code = await assemble(ctx, { model: 'deepseek-v4-flash', messages: [] })
+      .catch((error: unknown) => (error as LlmError).code)
+    expect(code).toBe(CONTEXT_WINDOW_EXCEEDED_CODE)
+  })
+
+  it('classifies only context-capacity HTTP 400 details as context overflow', () => {
+    expect(httpErrorCode(400, { message: 'request too large for model context' }))
+      .toBe(CONTEXT_WINDOW_EXCEEDED_CODE)
+    expect(httpErrorCode(400, { message: 'invalid input: temperature exceeds maximum allowed value' }))
+      .toBe('INVALID_REQUEST')
+    expect(httpErrorCode(413, { code: 'context_length_exceeded' })).toBe('HTTP_413')
+  })
+
   it('keeps the status-line message for JSON error bodies without a message', async () => {
     const server = await mockServer([{ kind: 'http-error', status: 500, body: '{"error":{"type":"x"}}' }])
     const ctx = await harness(server.url)