mcp-context-cost

pulumi — context cost

2,768 tokens across 12 tools — light (1–5K). Measured 2026-09-16 under methodology v1.0.

An Anthropic request carries 2,660 of those tokens as tool definitions, and Claude counts those at 4,671.

   
server (self-reported) @pulumi/mcp-server v0.2.0
status measured
tokenizer tiktoken / o200k_base
launch command npx -y @pulumi/mcp-server@latest stdio
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 none
canonical SHA-256 9eb845dee6bb274d3b93ba0ea67276b2829cb98cbe7ed01079eba7fb8263fa26
category vendor-official
source https://www.pulumi.com/docs/iac/using-pulumi/mcp-server/ (GitHub repo not public)

Where the tokens are

tool tokens share description input schema
pulumi-resource-search 1,011 36.5% 735 219
neo-task-launcher 226 8.2% 25 180
pulumi-registry-get-type 220 7.9% 11 185
pulumi-registry-get-function 217 7.8% 8 185
pulumi-registry-get-resource 214 7.7% 8 182
pulumi-registry-list-resources 174 6.3% 10 139
pulumi-registry-list-functions 173 6.3% 10 139
pulumi-cli-stack-output 123 4.4% 10 90
pulumi-cli-preview 104 3.8% 10 72
pulumi-cli-up 104 3.8% 10 72
pulumi-cli-refresh 104 3.8% 10 72
deploy-to-aws 96 3.5% 51 24

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 2,768 the badge number — every byte tools/list returned
o200k, Anthropic fields only 2,660 3.9% of the capture is MCP-only metadata
Claude, same fields 4,671 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
2026-08-16 2,768 12 not recorded not recorded —
2026-08-19 2,768 12 not recorded docker no change
2026-08-26 2,768 12 not recorded docker no change
2026-09-03 2,768 12 not recorded docker no change
2026-09-04 2,768 12 0.2.0 docker no change
2026-09-16 2,768 12 0.2.0 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/pulumi/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