API requests to Bedrock Mantle's OpenAI Responses API endpoint fail because of a signature mismatch

[nisanthchunduru]

Description

Hey OpenCode maintainers, I recently cloned opencode (to try GPT 5.5 and GPT 5.4 models that AWS Bedrock Mantle added (https://aws.amazon.com/blogs/aws/get-started-with-openai-gpt-5-5-gpt-5-4-models-and-codex-on-amazon-bedrock/)

I configured it AWS SigV4 auth (as my employer's security policies disallow us from creating long-term Bedrock API keys)

{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "amazon-bedrock": {
      "options": {
        "profile": "personal",
        "region": "us-east-2",
        "baseURL": "https://bedrock-mantle.us-east-2.api.aws/openai/v1"
      },
      "models": {
        "openai.gpt-5.4": {
          "id": "openai.gpt-5.4",
          "name": "OpenAI GPT-5.4",
          "provider": {
            "npm": "@ai-sdk/amazon-bedrock/mantle"
          }
        },
        "openai.gpt-5.5": {
          "id": "openai.gpt-5.5",
          "name": "OpenAI GPT-5.5",
          "provider": {
            "npm": "@ai-sdk/amazon-bedrock/mantle"
          }
        }
      }
    }
  }
}

Unfortunately, every API request to Bedrock Mantle OpenAI Resposnes API endpoint (except the API request for my first message) fails because of a signature mismatch

From a quick glance, it seems like the request is being modified after its signed

opencode/packages/opencode/src/provider/provider.ts

Line 1727 in 0050134

model.api.npm === "@ai-sdk/amazon-bedrock/mantle") &&

More specifically, opencode deletes the id property of all message items after the request is signed causing a signature mismatch

Can you please resolve this?

Thank you for your time.

Cc @rekram1-node @kitlangton

Plugins

No response

OpenCode version

local

Steps to reproduce

git clone https://github.com/anomalyco/opencode/i
git checkout b5cb9aae7f5f992ab401567d3427e122cd58719c
bun install
vim /tmp/opencode-local.json
 OPENCODE_CONFIG_CONTENT="$(< /tmp/opencode-local.json)" ~/.local/share/mise/installs/node/24/bin/bun run --cwd ~/repos/opencode/packages/opencode src/index.ts

// /tmp/opencode-local.json
{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "amazon-bedrock": {
      "options": {
        "profile": "your-aws-profile-name",
        "region": "us-east-2",
        "baseURL": "https://bedrock-mantle.us-east-2.api.aws/openai/v1"
      },
      "models": {
        "openai.gpt-5.4": {
          "id": "openai.gpt-5.4",
          "name": "OpenAI GPT-5.4",
          "provider": {
            "npm": "@ai-sdk/amazon-bedrock/mantle"
          }
        },
        "openai.gpt-5.5": {
          "id": "openai.gpt-5.5",
          "name": "OpenAI GPT-5.5",
          "provider": {
            "npm": "@ai-sdk/amazon-bedrock/mantle"
          }
        }
      }
    }
  }
}

Once OpenCode launches, send a message, wait for it to reply and send a message again

Screenshot and/or share link

No response

Operating System

No response

Terminal

No response

[nisanthchunduru]

Codex resolved this 1fa99cc

As I am unfamiliar with opencode's internals, I am unsure if that's the best to resolve this issue. In case it is, I am happy to raise a PR.

Thanks!

[rekram1-node]

I'm unable to reproduce, can u send me ur session? opencode export > session.json

[rekram1-node]

also that id omitting logic completely matches codex cli itself so this shouldn't be causing issues.

[nisanthchunduru]

@rekram1-node Thank you for getting back!

As far as I understand, ids are being removed after the request is signed thus causing a signature mismatch

also that id omitting logic completely matches codex cli itself so this shouldn't be causing issues.

Got it. I'll reproduce again and get back to you with more elaborate steps to reproduct. Please give me a day as I've a very busy day at work.

I'm unable to reproduce, can u send me ur session? opencode export > session.json

[rekram1-node]

i figured it out, wasnt familiar with this signing. Ill update it so we match codex here which shoudl fix ur issue