mcp-context-cost

sqlite — context cost

268 tokens across 6 tools — lean (< 1K). Measured 2026-09-16 under methodology v1.0.

An Anthropic request carries 268 of those tokens as tool definitions, and Claude counts those at 806.

   
server (self-reported) sqlite v0.1.0
status measured
tokenizer tiktoken / o200k_base
launch command uvx --with "mcp\<2" mcp-server-sqlite --db-path /tmp/test.db
isolation docker · ghcr.io/astral-sh/uv:python3.12-bookworm-slim · network bridge · linux/amd64 · network enabled for package fetch; clean FS, no host credentials
env vars supplied none
canonical SHA-256 d432983abc546eac2725c9db1a07f5f8dad0e6cbfb12f925c1d4fb61743d1c6b
category official-reference
source https://github.com/modelcontextprotocol/servers-archived

Where the tokens are

tool tokens share description input schema
write_query 50 18.7% 13 26
describe_table 49 18.3% 8 30
append_insight 49 18.3% 7 30
read_query 46 17.2% 8 27
create_table 45 16.8% 8 26
list_tables 28 10.4% 7 9

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 2026-09-14 against claude-opus-5 via Anthropic’s count_tokens (method tools-delta/v1).

  tokens  
o200k, full capture 268 the badge number — every byte tools/list returned
o200k, Anthropic fields only 268 0.0% of the capture is MCP-only metadata
Claude, same fields 806 3.01× 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.

Over time

date tokens tools release measured in change
2026-08-18 268 6 not recorded docker —
2026-09-04 268 6 0.1.0 docker no change
2026-09-16 268 6 0.1.0 docker no change

Full series: results/history.csv.

Re-derive it

npx -y mcp-context-cost verify results/sqlite/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.

Badge JSON · All servers · Leaderboard · Methodology