DurableAgent throws error for tools without execute function

[iNishant]

Problem

DurableAgent requires all tools in the toolset to have an execute function. When a tool doesn't have an execute function, it throws:

Error: Tool "task" does not have an execute function
    at executeTool (...)

The AI SDK's tool() function allows creating tools without execute functions, but DurableAgent doesn't support this pattern.

Environment

• ai: ^6.0.45
• @workflow/ai: 4.0.1-beta.51
• workflow: 4.0.1-beta.50

[pranaygp]

Related to #628, which tracks the broader issue of supporting provider-executed tools (AI SDK v6 / LanguageModelV3). Both issues stem from DurableAgent not supporting tools without execute functions. #628 addresses the validation phase (parseToolCall throwing NoSuchToolError), while this issue addresses the execution phase (executeTool throwing when execute is missing). These will likely need to be addressed together.

[pranaygp]

Update: PR #734 will partially address this issue by handling provider-executed tools (tools where the model sends providerExecuted: true on the tool call, like Google's googleSearch or OpenAI's web search).

However, #734 does not fully address #847. The remaining gap is:

• If a user defines a tool without an execute function (valid in AI SDK for human-in-the-loop or client-side tools)
• And the model calls that tool without the providerExecuted: true flag
• DurableAgent will still throw Tool X does not have an execute function

So #847 should remain open for this edge case after #734 is merged.

[pranaygp]

PR #734 has been merged, which addresses the provider-executed tools case (tools with providerExecuted: true like Google's googleSearch, OpenAI's web search, etc.).

This issue remains open for the remaining edge case: tools defined without an execute function that are NOT provider-executed (e.g., human-in-the-loop tools, client-side only tools).