mcpbench GitHub

client/bad-version-response

anthropic/claude-opus-4-8:medium 2025-11-25 docs: full score 0% musts 1/1 · shoulds 0/1 · mays 0/0 works yes · conformant yes

Checkpoints

MUST (any failure zeroes the score — 1/1 passed)

Checkpoint Description
sent-initialize Sent an initialize request

SHOULD (the score fraction — 0/1 passed)

Checkpoint Description Detail
disconnect-on-mismatch After the server negotiated an unsupported protocol version, sent nothing further after the unsupported version response, still sent notifications/initialized

Usage & cost

Nominal cost
$0.148
Input tokens
20
Output tokens
3,022
Cache read
53,267
Duration
50s
Timestamp
2026-07-17 22:27:22Z
Bench version
0.3.0

Cost is nominal (public API pricing): token usage × published rates; actual marginal cost is subscription-covered.