[DeepSeek DeepInfra] write tool repeatedly passes empty "content"

[NameIsHiki]

Description

When using DeepSeek V4 Flash via DeepInfra, both the write and edit tools repeatedly receive empty strings in the critical fields (content, newString).

The model can successfully write simple plain text ("hello world"), but fails as soon as it tries to write or edit content that contains HTML-like tags (<script>, </script>, etc.). This causes the agent to get stuck in a loop of failed tool calls.

Additional Observations

• The model is aware of the problem in its thinking trace and keeps trying again with the same empty fields.
• It sometimes leaks DSML fragments (｜DSML｜tool_calls>) in its output.
• Simple plain text works reliably. Any content with angle brackets (< / >) triggers the issue.

Plugins

No response

OpenCode version

1.14.48

Steps to reproduce

1. Start a new OpenCode session with DeepSeek V4 Flash via Deepinfra provider.
2. Ask the agent to create or modify a Svelte component (e.g. testComponent.svelte with a <script> tag).
3. Observe that simple "hello world" writes succeed.
4. When writing actual component code, the model starts generating tool calls with empty content.

Operating System

Windows 10

Terminal

Windows Terminal (cmd)

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• Either the < or <= operators are causing responses from the ai to get cut off. #23928: Similar report where < / <= characters in AI responses cause content to be cut off — the symptom of angle brackets triggering empty/truncated content in tool calls overlaps closely with this issue.
• Tool execution aborted when tool call is truncated (empty input) #13102: Tool execution aborted when tool call input is empty (truncation-related edge case with empty tool arguments).

If your issue is distinct (e.g., specific to the DeepInfra provider or DeepSeek's DSML output leaking into tool arguments), please add that context so maintainers can distinguish it from the above.

[NameIsHiki]

Update: I have isolated the root cause. This is a provider-side (DeepInfra) issue with their OpenAI-compatibility layer for DeepSeek-V4-Flash.

Through raw API testing, I’ve confirmed that their tool-call extractor fails specifically when the model's output contains angle brackets (<, >). Plain text works, but HTML/Svelte code results in empty strings in the tool arguments. Even when the arguments string returns as empty, the completion_tokens count shows activity. This confirms the model is indeed generating the code, but the provider-side extraction is failing to serialize it into the JSON response.

I have reported this to the DeepInfra team. For anyone else running into this, the current workaround is to use a different provider (like OpenRouter) which handles the DSML extraction correctly.