ai.proofslip/mcp-server

ProofSlip

Is the ProofSlip MCP server down? No. It answered initialize and tools/list in the probe of 2026-10-30.

Receipt-based verification for AI agent workflows — create, verify, and poll ephemeral proof objects

alive probed 2026-11-15 · unchanged since 2026-10-30

4tools

1.3ktokens in Claude Opus 5.5

0.7 %of Claude's 200k window

0.5×the median server

387 msto initialize

9 msto list tools

Run it: npx -y @proofslip/mcp-server@0.2.3 (stdio, probed in a container with the network off)
Host: npmjs.com
Reports itself as: proofslip 0.2.1
Capabilities: tools
Instructions: none
Of a 1M window: 0.1 % of a 1M context window
Count: 1.3k tokens in Claude Opus 5.5, exact, measured 2026-10-16. With the Claude Code prefix mcp__…__ on each tool name: 1.4k. The o200k_base estimate is 746. Counted again when the tool definitions change. Method.
Repository: https://github.com/Johnny-Z13/proofslip
Website: https://proofslip.ai
Registry: active, updated 2026-04-05 · registry entry

Most expensive tools

The Claude column scales the o200k estimate of each tool by this server's ratio of exact to estimate, 1.76×.

Tool	≈ Claude tokens	o200k estimate	Share of this server
create_receipt	658	374	50 %
check_receipt_status	239	136	18 %
verify_receipt	220	125	17 %
signup	195	111	15 %

Other registry entries on npmjs.com, the ones next to this name; all of them.

Servers that mention verification or ephemeral.

The result of the latest probe, the tool count and the token cost. The feed has an entry for every probe that changed them.

Stops answering, comes back, tool set or cost changes. One confirmation mail first, a stop link in every mail.