mcp-context-cost

sentry — context cost

6,455 tokens across 9 tools — moderate (5–15K). Measured 2026-08-16 under methodology v1.0.

   
server (self-reported) Sentry MCP v0.37.0
status measured
tokenizer tiktoken / o200k_base
launch command npx -y @sentry/mcp-server@latest
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 SENTRY_ACCESS_TOKEN
canonical SHA-256 b56928d7394324ec80ddda1377e382b535fd3abc7b488cda6b4a52e4a01b410b
category vendor-official
source https://github.com/getsentry/sentry-mcp

Where the tokens are

tool tokens share description schema
update_issue 1,306 20.2% 455 767
search_events 1,243 19.3% 459 718
search_issues 932 14.4% 377 496
get_sentry_resource 752 11.6% 397 287
analyze_issue_with_seer 726 11.2% 331 324
search_sentry_tools 584 9.0% 247 107
find_projects 421 6.5% 66 318
execute_sentry_tool 285 4.4% 138 90
find_organizations 204 3.2% 70 96

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 6,455 the badge number — every byte tools/list returned
o200k, Anthropic fields only 6,051 6.3% of the capture is MCP-only metadata
Claude, same fields 10,463 1.62× 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/sentry/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