Claude Code has an experimental 'mcp-cli' for invoking MCP servers (Google Workspace, GitHub, etc.) from bash.

Problem: it runs sequentially by default. My workflow hits 50+ MCP calls. That was 191 seconds—over 3 minutes waiting before Claude could synthesize anything.

I discovered you can orchestrate parallel calls within a single Bash tool invocation:

    mcp-cli call google/get_events '{}' > /tmp/cal.json &
    mcp-cli call google/list_tasks '{}' > /tmp/tasks.json &
    mcp-cli call github/list_issues '{}' > /tmp/issues.json &
    wait

The non-obvious part: this only works because background jobs (&) inherit the parent shell environment. Claude Code's session context—including MCP endpoint files—stays accessible.

If you spawn a new subshell (bash -c 'mktemp -d; mcp-cli...'), context breaks with "MCP endpoint file not found." That was the gotcha that took a while to figure out.

Benchmarks (verified January 2026):

    2 calls:  7.6s → 3.8s  (2x)
    10 calls: 38s  → 3.0s  (13x)
    20 calls: 76s  → 4.9s  (16x)
    50 calls: 191s → 10.3s (18x)

I packaged this into a self-contained toolkit:

- CLAUDE.md snippet with usage instructions - .claude/rules/ patterns (FORBIDDEN/REQUIRED examples) - Advisory hook that reminds about parallel patterns - Install script for project or user-level setup

https://github.com/AIntelligentTech/claude-code-mcp-cli-parallel-godmode

Requires ENABLE_EXPERIMENTAL_MCP_CLI=true (the mcp-cli is still experimental).

Curious if others are hitting similar bottlenecks or have found other optimisation patterns for MCP-heavy Claude Code workflows.