A scope authorises a read and says nothing about volume. An agent reads a
thousand records in seconds where a person clicks ten, and until now nothing
noticed: the token is valid, the tool is permitted, the ACL passes. That gap
stopped being theoretical the day an autonomous run started reading the whole
catalog on a schedule.
identifier: credential keys the counter on the sub claim — the end user,
whoever is asking on their behalf — so an agent looping under one person's
identity spends that person's budget and cannot spend everyone's. Verified on
catalog: pm-user and ro-user hold separate counters.
Per-route namespace, so a busy domain cannot exhaust another's.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The second ai-mcp-proxy binding (added to fix the GET/SSE 502 loop)
created a second runtime plugin instance with the same tool config,
which ai-mcp-proxy's own duplicate-name detection caught: all three
tools (list-customers/get-customer/create-customer) fell back to
auto-generated names across both instances. Confirmed via dataplane
pod logs right after applying the previous fix.
Real fix: one KongRoute for all three MCP HTTP methods (GET/POST/
DELETE) instead of two, one ai-mcp-proxy binding instead of two.
ai-mcp-proxy already tolerates multi-method routes (same "skips
method selection" notice the existing POST+DELETE route already
produces) — extending to GET is the same class of thing, not new
risk, and there is now exactly one plugin instance so no duplicate
tool names.
The stream route (GET, mcp/routes.yaml) had no ai-mcp-proxy binding,
so GET requests fell through to the KongService's own upstream
target (REST_HOSTNAME, i.e. Kong's own external hostname) and
looped back into the Gateway, growing response headers each pass
until nginx rejected them (502, "upstream sent too big header").
Confirmed via customers dataplane pod logs while debugging a
LibreChat connection failure. catalog-mcp has the same structural
gap but happens to 405 instead of looping there — not touched here.
Stéphane Tailland