The official GitHub MCP server adds up to 42,000 tokens of schema overhead per agent call, consuming 21% of a 200K context window before any real work begins. For production and multi-tenant B2B workloads, a thin REST API adapter with GitHub App authentication eliminates this tax, provides higher rate limits, and removes mandatory Copilot license dependencies.
The official GitHub MCP server charges roughly 42,000 tokens before your agent does any real work — that's 21 percent of a 200K context window spent on tool definitions alone. Two independent community measurements confirm the number, and a later count pushed it to 55,000 tokens across 93 distinct tool definitions as GitHub added surface area. If you're running production agent workloads against GitHub, this tax compounds on every single model call, as outlined in the related GitHub issue.
The 42K Token Problem Is a Schema Tax, Not a Feature Gap
The overhead comes almost entirely from verbose JSON Schema definitions that MCP requires for every tool — parameter types, descriptions, examples, and error formats all inline.
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