feat(ai-gateway): support AWS Bedrock SigV4 auth for custom LLMs

[kilo-code-bot]

Summary

• Add an optional aws_bedrock block (access_key_id, secret_access_key, region) to CustomLlmDefinitionSchema. When present, the custom LLM provider uses AWS SigV4 signing against the bedrock service instead of an Authorization: Bearer header.
• Introduce an optional signRequest hook on Provider; upstream-request.ts invokes it to compute auth headers (and optionally rewrite the target URL) before fetch. Non-Bedrock providers keep the existing Bearer flow unchanged.
• New bedrock-signer.ts rewrites the URL to https://bedrock-runtime.<region>.amazonaws.com/model/<internal_id>/invoke (or invoke-with-response-stream when body.stream === true) and signs with @aws-sdk/signature-v4 + @aws-crypto/sha256-js.

Admins configure a Bedrock-backed custom LLM via the existing JSON editor, e.g.:

{
  "internal_id": "anthropic.claude-sonnet-4-20250514-v1:0",
  "base_url": "https://bedrock-runtime.us-east-1.amazonaws.com",
  "api_key": "",
  "aws_bedrock": {
    "access_key_id": "...",
    "secret_access_key": "...",
    "region": "us-east-1"
  },
  "remove_from_body": ["model"],
  "extra_body": { "anthropic_version": "bedrock-2023-05-31" },
  "openclaw_settings": { "api_adapter": "anthropic-messages" }
}

Verification

Manually inspected the diff; the Bedrock path is only exercised when aws_bedrock is set on a custom LLM definition, otherwise upstream-request.ts falls through to the existing Bearer auth. Did not run pnpm typecheck/pnpm test/pnpm format locally before pushing per user instruction — please verify in CI.

Visual Changes

N/A — no UI changes; the admin JSON editor already accepts the new aws_bedrock field.

Reviewer Notes

• @aws-sdk/signature-v4 and @aws-crypto/sha256-js added to apps/web/package.json; pnpm install required.
• Credentials are stored plaintext in custom_llm2.definition jsonb, matching the existing api_key storage model for custom LLMs (admin-only, kilo-internal/*). If we want envelope-encrypted storage like byok_api_keys, that's a separate follow-up.
• parseStreamFlag in bedrock-signer.ts reads stream from the already-serialized body; admins should NOT include "stream" in remove_from_body, otherwise streaming requests will be routed to the non-streaming endpoint.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (2 files)

• apps/web/src/lib/ai-gateway/providers/get-provider.ts
• apps/web/src/lib/ai-gateway/providers/upstream-request.ts

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_{Reviewed by gpt-5.5-2026-04-23 · 387,699 tokens}