[BUG] Kiro provider returns 400 "Improperly formed request" when used via Agent (OpenCode)

[tonvarex]

OmniRoute Version

3.7.9

Installation Method

npm (global)

Operating System

Windows

OS Version

Windows 11

Node.js Version

22.22.2

Provider(s) Involved

Kiro

Model(s) Involved

kr/claude-opus-4.7, kr/claude-opus-4.6, kr/claude-sonnet-4.6, kr/claude-sonnet-4.5, kr/claude-haiku-4.5

Client Tool

OpenCode

Description

When using the Kiro provider through an agent (e.g., OpenCode), OmniRoute returns a 400 error with the message "Improperly formed request". However, the same provider and model work perfectly fine when used directly in the standard chat interface.

Steps to Reproduce

1. Configure Kiro provider in OmniRoute.
2. Select an agent (OpenCode) and attempt to run a task using a Kiro model (e.g., kr/claude-opus-4.7).
3. Observe the 400 Improperly formed request error in the logs.
4. Switch to the direct chat interface with the same model and observe that it works.

Expected Behavior

Agent requests should be formatted correctly and accepted by the Kiro provider, consistent with chat requests.

Actual Behavior

Agent requests fail with HTTP 400, leading to credential exhaustion/fallback.

Test Impact

Needs a new unit test

Error Logs / Output

[03:52:31.256] DEBUG: [sse] KIRO | claude-opus-4.7 | 3 msgs
[03:52:31.257] INFO: [sse] 0r5ckt pre_executor t=5ms {"attempt":0}
[ERROR] [400]: Improperly formed request.
❌ kiro [400]: [400]: Improperly formed request.
[03:52:31.639] INFO: [sse] 0r5ckt post_executor t=387ms {"status":400}
[03:52:31.660] WARN: [sse] Account df1fed88... unavailable (400), trying fallback

Screenshots

No response

Additional Context

No response

Validation Plan

No response

[kilo-code-bot]

This issue appears to be a duplicate of #2081.

[BUG]: 400 Improperly formed request when sending requests with 24 tools (#2081)

Similarity score: 95%

This comment was generated by Kilo Auto-Triage.

[falaraiza-debug]

This PR will solved that issues #2104

[diegosouzapw]

Thank you for the report, @tonvarex! This has been fixed in v3.8.0 via PR #2104 (fix(kiro): normalize tool-use payloads) by @rilham97, and PR #2105 (fix(kiro): merge adjacent user history turns after role normalization) by @Gioxaa.

The root cause was that Kiro's API requires strict tool-use payload normalization which wasn't being applied when requests came from agents like OpenCode. Both fixes are now merged. Please upgrade to v3.8.0 when available. 🎉

[tungnguyensnk]

@diegosouzapw 400 error is still happening

[Gioxaa]

@tungnguyensnk #2149 try out this one

[arsenal3008]

не помогает,

[Gioxaa]

@arsenal3008 The fix for this was merged in PR #2104, PR #2105 and PR #2149 , both targeting release/v3.8.0.

You're on 3.7.9 — the fix is not included in that version. Please update to 3.8.0 and the issue should be resolved.

[arsenal3008]

npm install -g omniroute@latest

[st2l]

API Error: 400 {"error":{"message":"Error from provider(omniroute,kr/claude-sonnet-4.5: 400): {\"error\":{\"message\":\"[400]: Improperly formed request.\",\"type\":\"invalid_request_error\",\"code\":\"bad_request\"}}Error: Error
     from provider(omniroute,kr/claude-sonnet-4.5: 400): {\"error\":{\"message\":\"[400]: Improperly formed request.\",\"type\":\"invalid_request_error\",\"code\":\"bad_request\"}}\n    at qn
     (/opt/homebrew/lib/node_modules/@musistudio/claude-code-router/dist/cli.js:582:7451)\n    at fD (/opt/homebrew/lib/node_modules/@musistudio/claude-code-router/dist/cli.js:582:11338)\n    at process.processTicksAndRejections
     (node:internal/process/task_queues:104:5)\n    at async cN (/opt/homebrew/lib/node_modules/@musistudio/claude-code-router/dist/cli.js:582:8659)","type":"api_error","code":"provider_response_error"}}

kiro ai provider. using a claude client.

Version is seen on screenshot and it is - 3.8.0
Sometimes models works, sometimes not. What should I do?

[hongmd]

@st2l I have the same issue with Claude code
[400]: Improperly formed request.