NVIDIA NIM kimik2.5 returns numeric tool call IDs causing 'expected id to be a string' error

Describe the bug

When using NVIDIA NIM kimik2.5 model with tool calls, the provider returns tool call IDs as numeric values instead of strings, causing Zod validation errors: expected id to be a string

To Reproduce

Configure NVIDIA NIM kimik2.5 as provider
Attempt a tool call (e.g., read, write, etc.)
Observe validation error in logs

Expected behavior

Tool calls should work seamlessly with NVIDIA NIM kimik2.5, automatically converting numeric IDs to strings.

Root Cause

NVIDIA NIM kimik2.5 returns tool call IDs as numbers (e.g., 123) instead of strings (e.g., "123"), violating OpenAI API specification which requires string IDs.

Environment

Provider: NVIDIA NIM
Model: kimik2.5
OpenCode version: latest

Same error happens using a local model loaded by lmstudio

same using NIM with any model.

same error using kimi k2.5 model nim

Same error using GLM 5.1

I've submitted a fix for this issue in PR #23592.

Root Cause: The Zod schemas in openai-compatible-chat-language-model.ts require id: z.string() for tool call IDs, rejecting numeric values.

Fix: Modified the schemas to accept both string and numeric IDs using z.union([z.string(), z.number().transform((v) => String(v))]). Numeric IDs are automatically coerced to strings, making the fix backward-compatible with all existing providers.

Changes:

Modified OpenAICompatibleChatResponseSchema tool_calls.id schema
Modified streaming chunk schema tool_calls.id similarly
Updated error message for missing ID
Added test case for numeric tool call IDs

Update: There's already an open PR #22612 that fixes this issue. It uses a similar approach with z.preprocess to coerce numeric IDs to strings. I've closed my duplicate PR #23592.

Please see #22612 for the fix.

fix(provider): coerce numeric tool call IDs for OpenAI-compatible pro…

Update: I've completely revised my fix in PR #23592.

What was wrong before: My initial fix modified the GitHub Copilot SDK (openai-compatible-chat-language-model.ts), which the maintainer correctly pointed out is only used for GitHub Copilot, not for other OpenAI-compatible providers like NVIDIA NIM.

Correct approach: The Zod validation for @ai-sdk/openai-compatible providers happens inside the external npm package, not in OpenCode's codebase. The correct fix is to intercept responses at the fetch wrapper level in provider.ts and coerce numeric tool call IDs to strings before the external SDK's Zod validation sees them.

The new fix:

Intercepts responses in the fetch wrapper (applies to ALL @ai-sdk/openai-compatible providers)
Handles both JSON responses and SSE streaming responses
Transforms numeric IDs to strings before the SDK processes them
No changes to the copilot SDK

I've reopened this work with a corrected approach. My previous PR (#23592) was auto-closed due to template issues, and the fix location was also wrong.

New PR: #23886

What changed:

The fix is now at the fetch wrapper level in provider.ts (correct location)
Applies to all @ai-sdk/openai-compatible providers (not just GitHub Copilot)
Handles both JSON and SSE streaming responses
Coerces numeric tool call IDs to strings before the external SDK's Zod validation

This addresses the maintainer's feedback that my first fix was in the wrong place (copilot SDK only). The new fix is in the right place and should work for NVIDIA NIM and any other OpenAI-compatible provider that returns numeric IDs.

fix(provider): coerce numeric tool call IDs for OpenAI-compatible pro…

Adding a second data point from a different NVIDIA model path.

I hit the same AI_InvalidResponseDataError: Expected 'id' to be a string in OpenCode with providerID=nvidia and modelID=z-ai/glm-5.1.

Relevant log evidence from my session:

C:\Users\zir\.local\share\opencode\log\2026-04-24T072123.log#L22327
The failing session is ses_2419f9a5bffeVdR1llFHd6IAIG
The log shows service=llm providerID=nvidia modelID=z-ai/glm-5.1
OpenCode then stops in session.processor with Expected 'id' to be a string.

I also saw an earlier NVIDIA 502 Bad Gateway in the same session, but the final hard stop was the id validation failure.

This looks like the same NVIDIA/OpenAI-compatible response-shape issue reported here, just on z-ai/glm-5.1 instead of kimik2.5.

That issue produces on most models which support openai endpoints. Also if you fix it locally the next error will occur:
Expected 'function.name' to be a string.

To stay organized issues are automatically closed after 60 days of no activity. If the issue is still relevant please open a new one.

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NVIDIA NIM kimik2.5 returns numeric tool call IDs causing 'expected id to be a string' error #19947

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NVIDIA NIM kimik2.5 returns numeric tool call IDs causing 'expected id to be a string' error #19947

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