Add mcp-tokens command to measure tool token costs#300
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Reports tiktoken-based token counts for every MCP tool exposed by the
codebase, sorted by cost. Useful for tracking tool-description token
budgets across revisions and spotting heavy tools when trimming.
- Snapshot mode prints a per-tool table with totals.
- `-json` emits the full export-tools-shaped JSON for downstream tools.
- `-base=<ref>` materialises the ref in a throwaway git worktree and
diffs token counts; supports text/markdown/json output.
rafaeljusto
reviewed
May 5, 2026
Swap github.com/pkoukk/tiktoken-go (stale since Sept 2025) for github.com/localit-io/tiktoken-go v0.2.1 (active fork) per PR review. Drop-in API; output and tests unchanged. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
rafaeljusto
approved these changes
May 6, 2026
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rafaeljusto
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Nice one! Only an optional comment that can be addressed in a future iteration (if required).
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Summary
cmd/mcp-tokensdev tool: tiktoken-based token counts for every MCP tool, sorted by cost.-jsonemits the same shape asmcp-http-cli export-tools.-base=<ref>materialises the ref in a throwawaygit worktreeand prints a diff (text/markdown/json).Test plan
go run ./cmd/mcp-tokens— snapshot table renders, total matches expectation.go run ./cmd/mcp-tokens -base=main— diff renders, working tree untouched.go test ./cmd/mcp-tokens/— smoke test passes.