Consolidate v1 MCP client utilities - #2467

Note

Medium Risk
Touches eval harness launch paths and MCP tool wiring across Null, Bash, Browser Use, and NeMo Gym; behavioral differences between Null and Bash modes in the unified program warrant careful regression testing.

Overview
Moves duplicated MCP HTTP client, retry, tool discovery, and call helpers into verifiers.v1.mcp.client, re-exported from verifiers.v1.mcp, and wires NeMo Gym’s upstream MCP calls through that shared mcp_client instead of a local session helper.

Adds standalone.py with launch_chat_program (shared CLI/MCP/initial-messages launch path) and inline_mcp_client (splices the client module source into PEP 723 sandbox scripts). Null and Bash now share minimal/program.py (Bash passes --bash plus edit/search/interception flags); null/program.py is removed. Browser Use drops its inlined MCP copy and uses the same embed + launch_chat_program pattern.

The shared minimal program keeps Null-specific behavior when --bash is off (60s MCP enumeration cap, graceful exit on context-overflow API errors) and Bash-specific behavior when on (longer HTTP timeouts, unbounded MCP connect wait, local tools gated by flags).

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Note

Consolidate v1 MCP client utilities into shared client.py and launch_chat_program

• Adds a reusable MCP client in client.py with mcp_client, with_retry, connect_mcp, mcp_content_to_chat_content, and call_mcp helpers, replacing per-harness duplicates
• Adds standalone.launch_chat_program and inline_mcp_client in standalone.py to centralize wire-argument passing and embed the MCP client into PEP 723 scripts at build time
• Refactors the bash, browser_use, and null harnesses to call launch_chat_program with the shared minimal.PROGRAM_SOURCE; deletes the standalone null program
• Unifies minimal/program.py to serve both Null and Bash harnesses via a --bash flag that enables bash tooling, unbounded MCP enumeration, and longer model timeout; without it, bash tooling is disabled and context-overflow errors terminate cleanly
• Refactors NeMoGymToolset.list_tools/call_tool in toolset.py to use the shared mcp_client helper with explicit timeouts
• Risk: minimal.program now relies on inlined shared functions (mcp_client, with_retry, connect_mcp, call_mcp, mcp_content_to_chat_content) being present at runtime via inline_mcp_client; if PROGRAM_SOURCE is constructed without calling inline_mcp_client, the script will fail with NameError

^{Macroscope summarized 1944f34.}