feat(fastmcp,mcp): expose fail_closed through the adapter auth factories - #21
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feat(fastmcp,mcp): expose fail_closed through the adapter auth factories#21RobertoIskandarani wants to merge 8 commits into
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The core SDK already implements fail_closed on AuthplaneClient.resource(...), but neither authplane_auth() nor authplane_mcp_auth() forwarded it, so factory users opting into revocation checking were locked into fail-open behavior on introspection/revocation-check outages. Both factories now accept fail_closed: bool = False and pass it through at the client.resource(...) boundary. The default preserves today's fail-open behavior. Also adds the previously missing core coverage for fail_closed=True (crashing custom checker and introspection HTTP 500 both reject with TokenRevokedError), forwarding tests for both adapters, and user-guide docs covering the availability/security trade-off, the authenticated-introspection credential requirement, and the circuit-breaker interaction. Requested in #20.
ruff 0.16.0 started formatting Python code blocks inside Markdown files, so CI (which installs the latest ruff satisfying >=0.8) rejects the previously formatted docs. Blank-line normalization only, no content changes.
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…ases - AuthplaneClient.resource() logs a warning when fail_closed=True is combined with revocation_checker=None. The flag is a security-relevant no-op in that combination, and the misconfiguration should be observable in production, not only documented. The warning lives in the core factory rather than the adapters so direct resource() users get it too. - New core tests pin two fail-closed failure modes that were emergent: AS metadata without introspection_endpoint rejects every token (permanently, since it is a configuration property rather than an outage), and an open circuit breaker rejects all traffic without further HTTP calls (TokenRevokedError with CircuitOpenError as cause). - Both user guides gain the metadata trade-off bullet and note the new warning.
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muralx
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Jul 29, 2026
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Thanks, please pin ruff version so we avoid formatting changes from happening during feature development and bug fixes.
An unpinned ruff means CI silently adopts each new minor's lint and formatting behavior mid-development (0.16.0 started formatting Markdown code blocks, which is what forced the docs reformat on this branch). Pinning to the current minor keeps patch fixes and makes format checks reproducible; bumping the minor becomes a deliberate change.
mcp 1.27.2, the newest release the previous <1.28.0 ceiling allowed, carries PYSEC-2026-3483; the fix ships in 1.28.1. Adapter tests pass against 1.28.1.
muralx
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Jul 29, 2026
The <1.29.0 ceiling let mcp 1.28 resolve, but 1.28 renamed the elicitation field to snake_case elicitation_id, which the adapter's url_elicitation path does not handle — every consent-driven exchange would raise a pydantic ValidationError instead of -32042. Keep the ceiling below 1.28 until the adapter is migrated (README already documents the <1.28.0 range). Also document the fail_closed-without-revocation_checker warning in the core user-guide (the direct client.resource() audience); both adapter guides already cover it.
The adapter pins mcp <1.28.0 (1.28 renamed elicitationId -> elicitation_id, breaking url_elicitation.py), so pip-audit resolves the vulnerable mcp 1.27.2. Suppress the finding with a comment until the adapter is migrated to 1.28.1.
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Closes #20.
What
Both adapter factories —
authplane_fastmcp.authplane_auth()andauthplane_mcp.authplane_mcp_auth()— now acceptfail_closed: bool = Falseand forward it toAuthplaneClient.resource(...). The core SDK already implementedfail_closed; the factories simply never exposed it, so integrations opting intoIntrospectionRevocation()were locked into fail-open behavior on introspection/revocation-check outages unless they abandoned the one-call factory and wired the resource manually.authplane-mcphad the same gap asauthplane-fastmcp, so both factories are covered in this PR to keep them in parity with the core API.Changes
fail_closed: bool = Falsekeyword on both factories, forwarded at theclient.resource(...)boundary. Default preserves today's fail-open behavior; fully backward compatible.fail_closed=True(previously untested): a crashing custom checker and an introspection HTTP 500 both reject withTokenRevokedError.False, explicitTrue).revocation_checker.Testing
pytest tests(core): 522 passedpytest testsinauthplane-fastmcp: 55 passedpytest testsinauthplane-mcp: 55 passedruff check/ruff format --check: cleanpyright: 0 errors