mcp-context-cost

neo4j-cypher — context cost

523 tokens across 3 tools — lean (< 1K). Measured 2026-09-30 under methodology v1.0.

An Anthropic request carries 354 of those tokens as tool definitions, and Claude counts those at 884.

   
server (self-reported) mcp-neo4j-cypher v2.13.3
status measured
tokenizer tiktoken / o200k_base
launch command uvx mcp-neo4j-cypher
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 NEO4J_URI, NEO4J_USERNAME, NEO4J_PASSWORD
canonical SHA-256 2e66ec7b2ea28f25f5b986a65cc950c06febad089b2c3033be49e15548f9c432
category vendor-official
source https://github.com/neo4j-contrib/mcp-neo4j

Where the tokens are

tool tokens share description input schema
get_neo4j_schema 238 45.5% 109 50
read_neo4j_cypher 143 27.3% 13 56
write_neo4j_cypher 143 27.3% 13 56

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 523 the badge number — every byte tools/list returned
o200k, Anthropic fields only 354 32.3% of the capture is MCP-only metadata
Claude, same fields 884 1.69× 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
2026-08-18 523 3 not recorded not recorded —
2026-08-19 523 3 not recorded docker no change
2026-09-04 523 3 2.13.3 docker no change
2026-09-05 523 3 2.13.3 docker no change
2026-09-09 523 3 2.13.3 docker no change
2026-09-30 523 3 2.13.3 docker no change

Some of these sweeps predate the isolation column, so the conditions they were measured under are not on record.

Full series: results/history.csv.

Re-derive it

npx -y mcp-context-cost verify results/neo4j-cypher/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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