MCP Inspector 2.3.0 adds per-server OAuth overrides and clears eight dependency advisories

The MCP Inspector reached 2.3.0 on 2026-08-19, one week after 2.2.0. The headline additions are all in authorization, which had been the tool's thinnest area for servers that do not follow the default discovery path.

Three OAuth features landed together. A server entry can now carry custom authorization-request parameters, so a provider that requires an extra query parameter at the authorize step can be exercised without patching the Inspector. Server Settings gained explicit Auth URL and Token URL overrides, which covers servers whose advertised metadata is wrong or absent. Connection Info now surfaces the id_token and decodes it, making the identity claims a server returns readable in the tool rather than requiring a separate decode step.

Several protocol-conformance fixes accompany them. Connect-time logging and setLevel are now gated on the negotiated protocol era rather than issued unconditionally, the web client reads modern tasks support from the extension map, the servers events stream accepts CRLF-delimited SSE frames, and resource templates expand per RFC 6570. List handling became more forgiving in one direction and stricter in another: a list result with one malformed entry now yields its valid entries instead of failing whole, while list-fetch failures in paginated mode are surfaced rather than silently swallowed.

The release also finishes a dependency clean-up. Pull request #2061 states the branch was opened against a tree carrying eight outstanding advisories, four of them high. Seven were cleared by #2059 (undici, hono, fast-uri, ip-address, qs, express-rate-limit and body-parser), and #2061 closed the eighth by bumping nanoid from 3.3.16 to 3.3.18 across five lockfiles to clear GHSA-2v37-7h3g-55p8, reached transitively through vite and postcss. After both, npm audit --omit=dev is reported clean at the root and in each of the four client installs. Separately, the Inspector now binds loopback by address and pins the sandbox port, which is what container deployments needed.