[Bug] Claude Desktop 使用 AWS Bedrock API Key 时错误转发到 bedrock-runtime /v1/messages，导致 HTTP 200 空响应

[JulianZJN]

Self Checks / 自检

• I have read the docs and checked the Claude Desktop provider setup.
• I searched existing issues for UnknownOperationException, Claude Desktop AWS Bedrock, and malformed response HTTP 200.
• I removed all API keys/tokens from this report.

CC Switch Version / 版本号

v3.15.0

Operating System / 操作系统

macOS, Apple Silicon

Related App / 涉及应用

• Claude Desktop third-party inference
• Claude Code in VS Code

Provider / 供应商

AWS Bedrock (API Key), region us-east-1

Summary / 问题概述

After switching the AWS Bedrock (API Key) provider through CC Switch, both Claude Desktop and Claude Code in VS Code became unusable.

Claude Desktop shows:

API Error: API returned an empty or malformed response (HTTP 200) — check for a proxy or gateway intercepting the request

The connection test in Claude Desktop / CC Switch can pass, but real chat requests fail.

VS Code Claude Code also fails when routed through this provider. Earlier it returned an invalid Bedrock model identifier when a CC Switch alias such as claude-sonnet-4-6 was forwarded; after changing models, requests still did not work reliably.

Evidence / 日志证据

With CC Switch debug logging enabled, the Claude Desktop request was forwarded to:

https://bedrock-runtime.us-east-1.amazonaws.com/v1/messages?beta=true

Example CC Switch log:

[Claude] >>> 请求 URL: https://bedrock-runtime.us-east-1.amazonaws.com/v1/messages?beta=true (model=global.anthropic.claude-sonnet-4-6)

The upstream AWS response body was:

{"Output":{"__type":"com.amazon.coral.service#UnknownOperationException"},"Version":"1.0"}

CC Switch then recorded it as:

status=200
input=0
output=0

Claude Desktop then surfaces this as an empty/malformed HTTP 200 response.

Manual verification / 手动验证

Using the same Bedrock API key, direct Bedrock Runtime invocation works when using the Runtime invoke endpoint:

POST https://bedrock-runtime.us-east-1.amazonaws.com/model/{modelId}/invoke
Authorization: Bearer <redacted>

The following model IDs returned valid responses in a direct minimal test:

global.anthropic.claude-opus-4-6-v1
global.anthropic.claude-sonnet-4-6
us.anthropic.claude-sonnet-4-5-20250929-v1:0

But bedrock-runtime.us-east-1.amazonaws.com/v1/messages returns UnknownOperationException, which seems expected because Bedrock Runtime is not the normal Anthropic-compatible /v1/messages base URL.

Expected Behavior / 期望行为

For an AWS Bedrock (API Key) provider:

1. Claude Desktop proxy mode should use the correct Bedrock Runtime invocation path/adapter, or use the correct Anthropic-compatible Bedrock endpoint if that is the intended mode.
2. AWS upstream errors like UnknownOperationException should be surfaced as errors instead of being treated/logged as a successful HTTP 200 with 0 tokens.
3. Claude Desktop and VS Code Claude Code should both be able to chat through the configured AWS Bedrock provider when the same API key works via direct Bedrock Runtime invocation.

Actual Behavior / 实际行为

1. Claude Desktop local gateway is configured as:

http://127.0.0.1:15721/claude-desktop

2. CC Switch forwards real chat traffic to:

https://bedrock-runtime.us-east-1.amazonaws.com/v1/messages?beta=true

3. AWS returns:

{"Output":{"__type":"com.amazon.coral.service#UnknownOperationException"},"Version":"1.0"}

4. CC Switch records status 200, input/output tokens 0, and Claude Desktop reports malformed response.

Possible Root Cause / 可能原因

It looks like the Claude Desktop proxy path treats the AWS Bedrock Runtime endpoint as if it were a normal Anthropic Messages-compatible endpoint and appends /v1/messages.

For Bedrock Runtime, direct invocation needs the Bedrock-style model invocation path, for example:

/model/{modelId}/invoke

or an equivalent Bedrock-specific adapter.

Additional Notes / 补充信息

I also tried disabling the Bedrock request optimizer, thinking optimization, cache injection, and rectifier settings, then restarting Claude Desktop and testing with short prompts. The same failure still occurred.

No API keys or tokens are included in this report.

[JulianZJN]

补充更新：\n\n- 回退到 CC Switch v3.14.1 后，删除 Bedrock 模型 ID 里的 [1M] 后缀，VS Code / Claude Code 这边已经恢复可用。\n- 但 Claude Desktop 3P / Gateway 仍然不可用。\n- 当前 Claude Desktop 3P profile 仍然使用：http://127.0.0.1:15721/claude-desktop。\n- Claude Desktop provider 的 AWS Bedrock API Key 配置仍是 apiFormat=anthropic + upstream https://bedrock-runtime.us-east-1.amazonaws.com。\n- 因此 Desktop 路径看起来仍会把请求当成 Anthropic /v1/messages 转发到 Bedrock Runtime，而 Bedrock Runtime 需要的是 /model/{modelId}/invoke 这类原生调用路径。\n\n所以目前可以确认：VS Code 的问题可通过 v3.14.1 + 去掉 [1M] 临时规避；Claude Desktop 仍是单独的 Bedrock Runtime 代理适配问题。

[JulianZJN]

补充：我检查了几个已关闭的相关 issue，结论如下（无任何密钥/个人路径）：\n\n- #707 / #1433：都是 AWS Bedrock 的 invalid beta flag / Anthropic beta 参数不兼容问题。已给出的 workaround 是开启高级设置里的整流器，或在 provider env 中设置 CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1。这对 Claude Code 的 beta 参数问题有帮助，但不能解释本 issue 里的 Claude Desktop 失败，因为这里的上游响应是 Bedrock Runtime 的 UnknownOperationException。\n- #1679：作者提到健康检查对很多供应商不适用，应以实际使用为准。这与本 issue 中“测试通过但真实对话失败”的现象一致。\n- #934 / #1041：说明 Bedrock provider 支持是在 v3.11/v3.12 之后加入的，主要面向 Claude Code 的 Bedrock env / optimizer 路径。\n- #2620：曾怀疑 SSE 翻译问题，但 issue 后续确认原诊断不成立。因此本 issue 更像是 Claude Desktop 3P path 下 Bedrock Runtime adapter/endpoint 选择问题，而不是泛化的 SSE JSON framing 问题。\n\n当前已验证的本地 workaround：\n\n- 回退到 CC Switch v3.14.1，并删除 Bedrock model id 后缀里的 [1M]，VS Code / Claude Code 已恢复。\n- Claude Desktop 仍失败。\n\n当前 Claude Desktop 相关配置（脱敏后）：\n\n- Claude Desktop gateway: http://127.0.0.1:15721/claude-desktop\n- Provider: AWS Bedrock (API Key)\n- Provider mode: claude-desktop / proxy\n- API format: anthropic\n- Upstream base URL: https://bedrock-runtime.us-east-1.amazonaws.com\n- Model routes:\n - claude-haiku-4-5 -> us.anthropic.claude-sonnet-4-5-20250929-v1:0\n - claude-sonnet-4-6 -> global.anthropic.claude-sonnet-4-6\n - claude-opus-4-7 -> global.anthropic.claude-opus-4-6-v1\n\nAdditional verification:\n\n- Direct Bedrock Runtime invocation with the same API key style works when using the native Runtime endpoint shape:\n POST /model/{modelId}/invoke with Authorization: Bearer <redacted>\n- The same real model IDs above returned valid minimal responses through direct Bedrock Runtime invocation.\n- The failing Claude Desktop path appears to forward to:\n https://bedrock-runtime.us-east-1.amazonaws.com/v1/messages?beta=true\n- Bedrock Runtime returns a JSON body containing UnknownOperationException for that path, while the outer HTTP status can still appear as 200, which then becomes Claude Desktop's empty or malformed response (HTTP 200).\n\nSo the likely fix is not just enabling rectifier / disabling beta flags. Claude Desktop + AWS Bedrock provider probably needs a Bedrock-specific adapter for the Desktop gateway path, or the UI should prevent using bedrock-runtime as an Anthropic-compatible /v1/messages endpoint.

[JulianZJN]

这个 issue 写得太复杂，不方便维护者快速理解。我已经重新整理成更简洁的中文版本继续跟进：#3224\n\n旧 issue 先关闭，避免重复和信息过载。