Daily harness signal · September 30, 2026

One bad entry.
Not zero policy.

One implementation lesson · Configuration fault isolation

A malformed marketplace entry must not erase valid restrictions. Test the remaining policy’s actual effects, not just a validator’s warning, before trusting an enterprise plugin allowlist.

Fresh · source September 18, 2026

Keep the valid restrictions alive

Use when

Managed Claude Code deployments restrict plugin sources with strictKnownMarketplaces or blockedMarketplaces. Version 2.1.277 repairs a failure where one malformed entry silently disabled the whole enterprise marketplace policy.

Action

Require that repair or a reviewed equivalent. Before rollout, run claude doctor on a test machine with the candidate managed policy; resolve unexpected stripped-entry warnings. Preserve the intended allowlist: an absent strictKnownMarketplaces key means unrestricted, whereas [] blocks marketplace additions. Never delete the policy to silence validation errors. Add a malformed-sibling case to existing policy acceptance, rather than building another configuration system.

Acceptance check

In an authorized disposable fixture, use owned inert catalogs A and B. First prove the valid allowlist admits A and denies B; separately, prove the valid blocklist denies B while A remains usable. Append {"source":"github","repo":17} to each array, one policy at a time. Require a diagnostic identifying the rejected entry, unchanged valid-entry enforcement, and no denied-source fetch or materialization. Cover fresh addition and fetch/update from B registered before policy. Retain version, exact configuration, diagnostics, request logs, and filesystem comparisons. Remove the malformed entry and recheck A. A warning without enforcement fails; blocking everything also fails the positive control.

Evidence

Anthropic’s dated release explicitly names the repair. Current documentation describes managed-entry tolerance, diagnostics, and source checks before network/filesystem operations. Issue 77315 includes a maintainer-account reproduction of stale editor schema rejecting runtime-valid Git URLs: editor validation alone is not deployment evidence. A separate public reproduction records policy errors alongside successful marketplace installation, reinforcing the need to inspect effects.

Caveat

Those historical reports do not independently validate this repair. No public parser implementation, passing regression output, or post-fix canary was inspected. Entirely invalid fields and invalid JSON need separate acceptance; do not infer universal fail-closed parsing. Marketplace admission does not establish plugin safety, revoke loaded code, or govern every sideloaded customization. This fixture is our unexecuted adaptation, not an upstream test. No installation, policy change, or evaluation is authorized by this newsletter.

Compact source notes

  1. Claude Code 2.1.277, September 18, 2026: vendor-confirmed whole-policy repair. September 19 release concerns classifier billing and supplies no reversal; neither establishes the latest version.
  2. Managed-settings validation and marketplace restrictions, undated, retrieved today. Current docs cover add/install/update/refresh/auto-update and tolerate individual invalid managed entries. Their general tolerance text cites 2.1.169; the specific marketplace repair is dated later. Do not treat that older minimum as proof this edge case was fixed. User/project/local settings remain strict.
  3. Schema/runtime mismatch, July 13–August 31, 2026; August 16 maintainer-account confirmation on 2.1.233 is signed as generated with Claude Code. This documents historical schema drift, not a current SchemaStore defect or the malformed-entry bug.
  4. 2.1.220 warning/effect report, July 30, with public reproduction commands and result tables. Author-reported, not run here; first/second-launch behavior differs. Tests for malformed siblings and pre-registered denied sources are our additions.
  5. Anchor lens: specific vendor repair, documented policy semantics and historical diagnostic/effect discrepancies. Unity lens: isolate configuration faults without widening surviving authority; proposed invariant. Source contracts: confidence_confirmed; adaptation: confidence_likely. Any admitted B fetch after adding the malformed sibling falsifies the gate.