mcp-context-cost

brave-search — context cost

25,456 tokens across 8 tools — heavy (15–30K). Measured 2026-08-16 under methodology v1.0.

   
server (self-reported) brave-search-mcp-server v2.1.0
status measured
tokenizer tiktoken / o200k_base
launch command npx -y @brave/brave-search-mcp-server
isolation docker · public.ecr.aws/docker/library/node:22-slim · network bridge · network enabled for package fetch; clean FS, no host credentials
env vars supplied BRAVE_API_KEY
canonical SHA-256 e5a8f43437056e6e89bb8f5167f5b8d471ba42de915ede953ce5968a84471582
category vendor-official
source https://github.com/brave/brave-search-mcp-server

Where the tokens are

tool tokens share description schema
brave_place_search 17,282 67.9% 351 1,143
brave_llm_context 2,550 10.0% 177 1,535
brave_local_search 1,415 5.6% 157 1,211
brave_web_search 1,396 5.5% 133 1,211
brave_news_search 1,002 3.9% 249 694
brave_image_search 814 3.2% 67 268
brave_video_search 688 2.7% 86 554
brave_summarizer 307 1.2% 154 101

Each tool is tokenized on its own, so the parts do not sum exactly to the whole: the array adds its own brackets and commas, and the tokenizer merges tokens across object boundaries. The badge number is always the count of the whole array, never a sum of parts.

What this costs on Claude

Measured 2026-08-16 against claude-opus-5 via Anthropic’s count_tokens (method tools-delta/v1).

  tokens  
o200k, full capture 25,456 the badge number — every byte tools/list returned
o200k, Anthropic fields only 8,262 67.5% of the capture is MCP-only metadata
Claude, same fields 13,746 0.54× the badge number

An Anthropic tool definition carries name, description, and input_schema and nothing else, so title, annotations, outputSchema, execution, and icons are dropped before the request — that is the second row. The third row is the same tools counted by Anthropic, which is larger than the second because Anthropic’s tokenizer is denser on this content than o200k_base and the API adds its own framing (at most 328 tokens of it fixed, measured against a single minimal tool). The two effects run in opposite directions, which is why the Claude number is not a fixed multiple of the badge.

Re-derive it

npx -y mcp-context-cost verify results/brave-search/measurement.json

That re-tokenizes the published capture and checks the count and the hash. If it disagrees with the badge, the badge is wrong — open an issue and it gets corrected.

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