feat(mcp): route shell as built-in MCP tool (PR 1 of 2)#1424
feat(mcp): route shell as built-in MCP tool (PR 1 of 2)#1424RohanSogani wants to merge 3 commits into
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Signed-off-by: Rohan Sogani <ronsogani@gmail.com>
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📝 WalkthroughWalkthroughAdds a new routed built-in tool type Changes
Sequence Diagram(s)sequenceDiagram
participant Client as Client
participant MG as ModelGateway
participant TF as Transformer
participant MCP as MCPServer
participant Tool as ShellTool
Client->>MG: request triggers tool call (shell_call)
MG->>MCP: route to routed builtin (builtin_type = Shell)
MCP->>TF: emit response with ResponseFormat::ShellCall
TF->>TF: parse shell action JSON, normalize id
TF->>MG: produce ResponseOutputItem::ShellCall (completed)
MG->>Client: stream final CALL_COMPLETED event (type="shell_call", id prefixed "sc")
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Code Review
This pull request introduces the Shell built-in tool type, updating the core configuration, session management, and routing utilities in the model gateway. Feedback suggests aligning the Shell response format with the protocol specification by using a dedicated variant instead of Passthrough. Additionally, several missing tool variants were identified: ImageGeneration should be added to the session's built-in tool list, and FileSearch needs to be included in the routing and extraction logic within mcp_utils.rs.
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⚠️ Outside diff range comments (1)
model_gateway/src/routers/common/mcp_utils.rs (1)
187-193:⚠️ Potential issue | 🟠 Major | ⚡ Quick win
file_searchis still omitted from builtin routing/extraction match arms.
ResponseTool::FileSearch(_)is missing in bothcollect_builtin_routingandextract_builtin_types, so requests using{"type":"file_search"}won’t enter MCP builtin routing through these helpers.🔧 Proposed fix
@@ let builtin_type = match tool { ResponseTool::WebSearchPreview(_) => BuiltinToolType::WebSearchPreview, ResponseTool::CodeInterpreter(_) => BuiltinToolType::CodeInterpreter, + ResponseTool::FileSearch(_) => BuiltinToolType::FileSearch, ResponseTool::ImageGeneration(_) => BuiltinToolType::ImageGeneration, ResponseTool::Shell(_) => BuiltinToolType::Shell, _ => continue, }; @@ .filter_map(|t| match t { ResponseTool::WebSearchPreview(_) => Some(BuiltinToolType::WebSearchPreview), ResponseTool::CodeInterpreter(_) => Some(BuiltinToolType::CodeInterpreter), + ResponseTool::FileSearch(_) => Some(BuiltinToolType::FileSearch), ResponseTool::ImageGeneration(_) => Some(BuiltinToolType::ImageGeneration), ResponseTool::Shell(_) => Some(BuiltinToolType::Shell), _ => None, })Also applies to: 229-235
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@model_gateway/src/routers/common/mcp_utils.rs` around lines 187 - 193, Builtin file_search is omitted from the mapping: update both collect_builtin_routing and extract_builtin_types match expressions to include ResponseTool::FileSearch(_) => BuiltinToolType::FileSearch so requests with {"type":"file_search"} are handled; add the same arm in the other match (the one around lines 229-235) to keep both helpers consistent and ensure the FileSearch variant is routed/extracted like WebSearchPreview/CodeInterpreter/ImageGeneration/Shell.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Outside diff comments:
In `@model_gateway/src/routers/common/mcp_utils.rs`:
- Around line 187-193: Builtin file_search is omitted from the mapping: update
both collect_builtin_routing and extract_builtin_types match expressions to
include ResponseTool::FileSearch(_) => BuiltinToolType::FileSearch so requests
with {"type":"file_search"} are handled; add the same arm in the other match
(the one around lines 229-235) to keep both helpers consistent and ensure the
FileSearch variant is routed/extracted like
WebSearchPreview/CodeInterpreter/ImageGeneration/Shell.
ℹ️ Review info
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Configuration used: Organization UI
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Run ID: 510a7055-521f-4d8c-88b8-acb38d7c0c21
📒 Files selected for processing (3)
crates/mcp/src/core/config.rscrates/mcp/src/core/session.rsmodel_gateway/src/routers/common/mcp_utils.rs
Signed-off-by: Rohan Sogani <ronsogani@gmail.com>
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Signed-off-by: Rohan Sogani <ronsogani@gmail.com>
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⚠️ Outside diff range comments (1)
model_gateway/src/routers/openai/mcp/tool_loop.rs (1)
624-635:⚠️ Potential issue | 🟠 Major | ⚡ Quick winDon't strip the shell
call_idin the non-streaming path.Unlike the other hosted formats,
shell_callkeeps both an output-itemidand the originalcall_id. By addingResponseFormat::ShellCallto this normalization branch,build_transformed_mcp_call_item()now feedsto_shell_call()the stripped item-id source, so a normal upstream pair likeid = "fc_123"/call_id = "call_123"is emitted asid = "sc_123"/call_id = "123". That breaks downstream correlation for follow-up shell items. Keep the rawcall_idfor shell and normalize only the outward-facingid.🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@model_gateway/src/routers/openai/mcp/tool_loop.rs` around lines 624 - 635, The function non_streaming_tool_item_id_source is incorrectly stripping prefixes for ResponseFormat::ShellCall; remove ShellCall from the branch that normalizes item IDs so shell call_ids remain raw. Update non_streaming_tool_item_id_source to treat ResponseFormat::ShellCall (and any shell-specific path) as a passthrough that returns item_id.to_string(), leaving the existing stripping behavior for WebSearchCall, CodeInterpreterCall, FileSearchCall, ImageGenerationCall, and ShellCall removed from that normalization branch; this preserves call_id when build_transformed_mcp_call_item() later calls to_shell_call().
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Outside diff comments:
In `@model_gateway/src/routers/openai/mcp/tool_loop.rs`:
- Around line 624-635: The function non_streaming_tool_item_id_source is
incorrectly stripping prefixes for ResponseFormat::ShellCall; remove ShellCall
from the branch that normalizes item IDs so shell call_ids remain raw. Update
non_streaming_tool_item_id_source to treat ResponseFormat::ShellCall (and any
shell-specific path) as a passthrough that returns item_id.to_string(), leaving
the existing stripping behavior for WebSearchCall, CodeInterpreterCall,
FileSearchCall, ImageGenerationCall, and ShellCall removed from that
normalization branch; this preserves call_id when
build_transformed_mcp_call_item() later calls to_shell_call().
ℹ️ Review info
⚙️ Run configuration
Configuration used: Organization UI
Review profile: ASSERTIVE
Plan: Pro
Run ID: 0edb13b8-745f-4662-8c53-21781250d316
📒 Files selected for processing (7)
crates/mcp/src/core/config.rscrates/mcp/src/transform/transformer.rscrates/mcp/src/transform/types.rsmodel_gateway/src/routers/common/mcp_utils.rsmodel_gateway/src/routers/grpc/common/responses/streaming.rsmodel_gateway/src/routers/grpc/harmony/streaming.rsmodel_gateway/src/routers/openai/mcp/tool_loop.rs
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Description
Problem
SMG can route several OpenAI Responses built-in tools to MCP servers via
builtin_type, includingweb_search_preview,code_interpreter,file_search, andimage_generation.The
shellResponses tool was already represented in the protocol layer, but it was not available as a routable MCP built-in type. As a result, a request declaring{"type":"shell"}could not be matchedto a configured MCP server using
builtin_type: shell.Additionally, mapping shell to generic MCP passthrough would expose the routed call as an
mcp_call, even though the Responses protocol has a nativeshell_calloutput item.Solution
Add
shellto the existing built-in MCP routing path, matching the pattern used for the other built-in tools.BuiltinToolType::Shellmaps to:shellshell_callResponseTool::Shell(_)This keeps the first upstream slice focused on shell routing and native
shell_callresponse-format alignment.Full hosted-shell output parity is intentionally left for a follow-up. OpenAI documents shell runs as paired output items:
shell_callfor the requested commands andshell_call_outputfor command outputand exit outcomes. That follow-up will add the broader one-tool-result-to-multiple-output-items plumbing needed for
shell_call_output.Reference: https://platform.openai.com/docs/guides/tools-shell#shell-output-in-responses
Changes
BuiltinToolType::Shell.shellbuilt-in type.ResponseFormatConfig::ShellCall.ResponseFormat::ShellCall.BuiltinToolType::ShelltoResponseFormatConfig::ShellCall.ResponseOutputItem::ShellCallinstead of generic passthrough.ResponseTool::Shell(_)in built-in MCP routing and extraction.BuiltinToolType::Shellin MCP session built-in binding detection.shell_callwithsc_item IDs instead of genericmcp_call.{"type":"shell"}routes to a configured MCP server withbuiltin_type: shell.ResponseFormat::ShellCallproducesResponseOutputItem::ShellCall.Test Plan
Repro from repo root:
Summary by CodeRabbit