openclaw - 💡(How to fix) Fix [Bug]: Kilo provider payload rejection on chat completions (expected array, received string)

Description

When running cron tasks or nested subagents calling deepseek-v4-flash via the kilo provider, the LLM request fails with:

embedded run agent end: runId=... error=LLM request failed: provider rejected the request schema or tool payload. rawError=400 Invalid input: expected array, received string

Cause

In standard OpenAI-compatible API specifications, the stop parameter (representing stop sequences) can be parsed either as a single string (e.g. "stop": "\n") or a JSON array of strings (e.g. "stop": ["\n"]).

The Kilo.ai Gateway and deepseek validation schemas are strictly configured to accept only a JSON array for the stop parameter. When OpenClaw serializes the payload passing a raw string for stop, the provider's API rejects the entire payload with a 400 Bad Request validation error.

Location of the Issue

The payload transformation for the Kilocode/Kilo provider is handled by createKilocodeWrapper in src/plugin-sdk/src/plugin-sdk/provider-stream.ts (compiled to /dist/proxy-stream-wrappers-B-pawBvX.js):

function createKilocodeWrapper(baseStreamFn, thinkingLevel) {
    // ...
    return streamWithPayloadPatch(underlying, model, context, {
        ...options,
        headers
    }, (payload) => {
        normalizeProxyReasoningPayload(payload, thinkingLevel);
    });
}

Proposed Fix

We can safely normalize payload.stop within the payload patch function inside createKilocodeWrapper to convert a single string into a single-element array, keeping it fully compliant with Kilo's strict validation schema:

function createKilocodeWrapper(baseStreamFn, thinkingLevel) {
    // ...
    return streamWithPayloadPatch(underlying, model, context, {
        ...options,
        headers
    }, (payload) => {
        normalizeProxyReasoningPayload(payload, thinkingLevel);
        if (payload && typeof payload === "object" && typeof payload.stop === "string") {
            payload.stop = [payload.stop];
        }
    });
}

This preserves expected behavior for downstream callers while ensuring robust compatibility with Kilo's API endpoint.