[cunninghamcard-bit]

Summary

Before: Hugging Face do_generate marked every mcp_call / mcp_list_tools tool-call and tool-result dynamic: true. @ai-sdk/huggingface 2.0.62 sets no dynamic flag on them.

After: the four parts carry no dynamic flag, as upstream. Without a local tool of that name, generate_text now returns the MCP call marked invalid (NoSuchTool), which is what the AI SDK's parseToolCall does for a provider-executed call that is not dynamic.

Found while porting the upstream Hugging Face tests (#303, case doGenerate › basic text response › should handle MCP tools with annotations). Part of the #276 list. First of three stacked Hugging Face fixes; the next two are the tool-result and stream-error PRs.

How it works today

HuggingFaceResponsesModel::do_generate                 aimux-providers/src/huggingface/responses.rs:163   // upstream: HuggingFaceResponsesLanguageModel.doGenerate  huggingface-responses-language-model.ts
└─ build_generate_content(&response)                   responses.rs:933                                   // upstream: for (const part of response.output) :220
   ├─ "mcp_call"                                        responses.rs:1013                                  // upstream: case 'mcp_call' :264
   │  ├─ RawToolCall { provider_executed: true, dynamic: Some(true) }   :1026                              //   { type: 'tool-call', providerExecuted: true }   no dynamic
   │  └─ ToolResult { dynamic: Some(true) }            :1037                                              //   { type: 'tool-result' }                          no dynamic
   └─ "mcp_list_tools"                                  responses.rs:1043                                  // upstream: case 'mcp_list_tools' :284
      ├─ RawToolCall { dynamic: Some(true) }           :1051
      └─ ToolResult { dynamic: Some(true) }            :1062
generate_text → parse_tool_call                         aimux-core/src/parse_tool_call.rs:160              // upstream: parseToolCall
   provider_executed && dynamic → skip the tool lookup  :168   → valid call although no local tool exists

What this PR changes

build_generate_content                                 responses.rs:933
├─ "mcp_call"        RawToolCall / ToolResult { dynamic: None }      :1026 / :1037   ← upstream :264-281
└─ "mcp_list_tools"  RawToolCall / ToolResult { dynamic: None }      :1051 / :1062   ← upstream :284-301
generate_text → parse_tool_call                         parse_tool_call.rs:160
   provider_executed, not dynamic, no local tool → returned as an invalid call (NoSuchTool), as upstream parseToolCall

Tests: should_handle_mcp_tools_with_annotations (tests/huggingface_responses_test.rs) asserted that the call passes Core validation without local tools; it now expects the invalid call. The full upstream case is in #303.

Docs: CHANGELOG Fixed.

Type of change

• Bug fix (non-breaking)
• New feature (non-breaking)
• Breaking change
• New provider
• New / updated binding
• Docs / RFC

Checklist

• cargo +1.99 fmt -p aimux-providers -- --check passes
• cargo +1.99 clippy -p aimux-providers --lib --tests -- -D warnings passes
• cargo +1.99 test -p aimux-providers --test huggingface_responses_test passes (32)
• scripts/check_provider_boundaries.sh passes
• Updated relevant docs (CHANGELOG)
• Commit messages follow Conventional Commits

Notes for reviewers

A caller that relied on the MCP call passing validation without a local tool now gets an invalid tool call, the same result the AI SDK gives.

🤖 Generated with Claude Code

https://claude.ai/code/session_01RoxcKU4zBD64Lri3e4Lrq5

[cunninghamcard-bit]

Folded into #307 together with the other Hugging Face fixes, so each vendor has one fix PR. This change is commit 26cf0a83 there. Closing this one; the branch stays as it is.

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