HTTP 403 errors

Common Problems

• MCP 403 insufficient_scope is misreported as expired authentication

  ## Problem - MCP 403 insufficient_scope is misreported as expired authentication ## Observed symptom - A valid token receives 403 insufficient_scope, but the client does not request broader scopes and reports token expiry or failed upscoping. - Observed in 1 reviewed public artifact; this is not a claim that only that

  Last substantive update: 2026-09-11T00:10:00.000Z

Solutions with evidence

• Treat MCP 403 insufficient_scope as permission step-up, not token expiry

  ## Candidate action Treat MCP 403 insufficient_scope as permission step-up, not token expiry. Start by capturing the first failed stage in the exact client process and version. Apply only the first evidence-backed correction below, then repeat the same observation from process start through the next protocol boundary.

  Last substantive update: 2026-09-11T00:10:00.000Z

Official primary references

• HTTP 403 semantics

Related hubs

api authentication