Server

Stack Overflow

by StackOverflow

Endpoint
https://mcp.stackoverflow.com
Transport
Streamable HTTP
Access
Public Anyone can connect; where an account is needed, anyone can create one by self-service sign-up. Manual check · jbspeakr (documentation pass with Claude Code) · · evidence · Any Stack Overflow account can authenticate, limited to 100 calls per day per user (contact sales for more).
Auth
OAuth An OAuth 2.x authorization obtained through the server's authorization server. Manual check · jbspeakr (documentation pass with Claude Code) · · evidence · Browser login to Stack Exchange and a consent step authorizing the client; the page describes the flow without naming OAuth.
Why it is listed
Listed because it appears in a public directory of MCP servers. Source
Homepage
https://stackoverflow.com

Against MCP Authorization 2026-07-28current

  • Unsupported 3
  • Unknown 20

Passive scanGrade F · · Report

Contribute a correctionWithdraw this serverJSON

Older revisions of the matrix: 2025-11-25

MCP server features 13

FeatureLevelStatusObservedEvidence
Protected Resource Metadata servedmcp.prm · Discovery · Authorization Server Discovery › Authorization Server LocationMUSTUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
PRM lists an authorization servermcp.prm.authorization-servers · Discovery · Authorization Server Discovery › Authorization Server LocationMUSTUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
PRM lists scopes_supportedmcp.prm.scopes-supported · Discovery · Authorization › Scope Selection StrategyMAYUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
PRM reachable at a well-known URImcp.prm.well-known · Discovery · Authorization Server Discovery › Protected Resource Metadata Discovery RequirementsMUSTUnsupportedPassive scan · scanner@0.3.0source— HTTP 404; not at either well-known location (root HTTP 404)
1 earlier observation
  1. Unsupported · Passive scan · scanner@0.2.0 · evidence
resource_metadata in the 401 challengemcp.prm.www-authenticate · Discovery · Authorization Server Discovery › Protected Resource Metadata Discovery RequirementsMUSTUnsupportedPassive scan · scanner@0.3.0source— HTTP 401; WWW-Authenticate: Bearer, no resource_metadata parameter
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
403 insufficient_scope for step-upmcp.rs.insufficient-scope · Authorization · Authorization › Scope Challenge HandlingSHOULDUnknown no observationno observation yet
Scope in the WWW-Authenticate challengemcp.rs.scope-challenge · Authorization · Authorization › Scope Selection StrategySHOULDUnsupportedPassive scan · scanner@0.3.0source— HTTP 401; WWW-Authenticate: Bearer, no scope parameter
No offline_access in advertised scopesmcp.prm.no-offline-access · Tokens · Authorization › Refresh TokensSHOULDUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
401 for missing or invalid tokensmcp.rs.401-on-invalid · Tokens · Authorization › Token HandlingMUSTUnknown no observationno observation yet
Audience validationmcp.rs.audience-validation · Tokens · Security Considerations › Access Token Privilege RestrictionMUSTUnknown no observationno observation yet
Bearer token only in the Authorization headermcp.rs.bearer-header · Tokens · Authorization › Access Token UsageMUSTUnknown no observationno observation yet
No token passthrough to upstream APIsmcp.rs.no-passthrough · Delegation · Security Considerations › Access Token Privilege RestrictionMUSTUnknown no observationno observation yet
Per-client consent on proxy serversmcp.proxy.consent · Consent · Security Considerations › Confused Deputy ProblemMUSTUnknown no observationno observation yet

Authorization server features 10

FeatureLevelStatusObservedEvidence
Metadata issuer matches the discovery URLmcp.as.issuer-match · Discovery · Authorization Server Discovery › Authorization Server Metadata DiscoveryMUSTUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
Authorization server metadata discoverablemcp.as.metadata · Discovery · Authorization Server Discovery › Authorization Server Metadata DiscoveryMUSTUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
Client ID Metadata Documents supportedmcp.as.cimd · Registration · Client Registration › Client ID Metadata DocumentsSHOULDUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
Dynamic Client Registration offeredmcp.as.dcr · Registration · Client Registration › Dynamic Client RegistrationMAYUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
2 earlier observations
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
  2. Unknown · Vendor claim · jbspeakr · evidence
Documented pre-registration pathmcp.as.preregistration · Registration · Client Registration › Pre-registrationSHOULDUnknown no observationno observation yet
Issuer identifier in authorization responsesmcp.as.iss-param · Authorization · Authorization › Authorization Response ValidationSHOULDUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
PKCE with S256 advertisedmcp.as.pkce-s256 · Authorization · Security Considerations › Authorization Code ProtectionMUSTUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence
Refresh token rotation for public clientsmcp.as.refresh-rotation · Tokens · Security Considerations › Token TheftMUSTUnknown no observationno observation yet
Resource indicators honouredmcp.as.resource-indicator · Tokens · Security Considerations › Token Audience Binding and ValidationMUSTUnknown no observationno observation yet
All endpoints served over HTTPSmcp.as.https · Transport · Security Considerations › Communication SecurityMUSTUnknownPassive scan · scanner@0.3.0source— HTTP 404; no protected resource metadata at a well-known location (HTTP 404) and none reached through the challenge (challenge without resource_metadata)
1 earlier observation
  1. Unknown · Passive scan · scanner@0.2.0 · evidence