mcp-context-cost

airtable — context cost

4,186 tokens across 16 tools — light (1–5K). Measured 2026-09-30 under methodology v1.0.

An Anthropic request carries 2,531 of those tokens as tool definitions, and Claude counts those at 4,555.

   
server (self-reported) airtable-mcp-server v1.14.0
status measured
tokenizer tiktoken / o200k_base
launch command npx -y airtable-mcp-server
isolation docker · public.ecr.aws/docker/library/node:22-slim · network bridge · linux/amd64 · network enabled for package fetch; clean FS, no host credentials
env vars supplied AIRTABLE_API_KEY
canonical SHA-256 5f90d662e26a77e01125999b97db0bf9204bb92bd0fc7297a28495986d80ec30
category community
source https://github.com/domdomegg/airtable-mcp-server

Where the tokens are

tool tokens share description input schema output schema
list_records 395 9.4% 5 269 86
describe_table 354 8.5% 7 260 52
upload_attachment 347 8.3% 48 198 61
list_tables 340 8.1% 7 239 59
list_comments 325 7.8% 5 122 163
create_comment 310 7.4% 6 118 145
search_records 277 6.6% 6 150 86
update_records 265 6.3% 9 129 86
update_field 214 5.1% 7 114 52
create_table 212 5.1% 7 112 52
create_field 206 4.9% 7 106 52
create_record 205 4.9% 7 96 61
delete_records 202 4.8% 5 92 64
update_table 195 4.7% 7 95 52
get_record 186 4.4% 6 84 61
list_bases 151 3.6% 6 24 84

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 4,186 the badge number — every byte tools/list returned
o200k, Anthropic fields only 2,531 39.5% of the capture is MCP-only metadata
Claude, same fields 4,555 1.09× 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
2026-08-16 4,207 16 not recorded not recorded —
2026-08-19 4,207 16 not recorded docker no change
2026-09-04 4,186 16 1.14.0 docker −21
2026-09-05 4,186 16 1.14.0 docker no change
2026-09-09 4,186 16 1.14.0 docker no change
2026-09-30 4,186 16 1.14.0 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/airtable/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