# AN-2026-0663: Supabase pg_graphql 1.6.0 disables GraphQL introspection by default (new projects from Jun 29, 2026): __schema / __type queries return "Unknown field \"__schema\" on type Query"

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- id: AN-2026-0663 (version 1; cite https://breakwire.org/claim/AN-2026-0663/v/1)
- kind: breaking · status: active · review: editor
- source: <https://supabase.com/changelog/46320-breaking-change-in-pg-graphql-1-6-0-graphql-introspection-disabled-by-default>
- event date: 2026-05-25
- services: supabase
- affected: pg_graphql >=1.6.0; supabase projects created on or after 2026-06-29; existing projects after upgrading pg_graphql to 1.6.0+ (e.g. via a Postgres upgrade); graphql-codegen, Relay compiler, Apollo DevTools, GraphiQL and other tools that call __schema or __type
- timeline:
  - 2026-06-29 (past): New projects ship pg_graphql 1.6.0+ with introspection disabled [statement 0]
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Supabase's changelog (opened 2026-10-29; rollout moved from 2026-06-15 to 2026-06-29 by an edit on 2026-06-13) says pg_graphql 1.6.0 disables GraphQL introspection by default; it ships in new Supabase projects from 2026-06-29. Existing projects are affected only after upgrading pg_graphql to 1.6.0+, for example by upgrading Postgres.  [✓0 ✗0]
1. From 1.6.0, __schema and __type queries return an error unless introspection is enabled; Supabase quotes it as {"errors": [{"message": "Unknown field \"__schema\" on type Query"}]}. Regular data queries (e.g. accountCollection) keep working.  [✓0 ✗0]
2. Affected tools named by Supabase: Studio's GraphQL explorer, external GraphiQL / GraphQL Playground, Apollo DevTools, the Relay compiler, code generators such as graphql-codegen, and anything calling __schema or __type.  [✓0 ✗0]

## Fix
```text
Enable introspection per schema: comment on schema public is e'@graphql({"introspection": true})'; if the schema already has a @graphql comment, merge the keys (e.g. {"inflect_names": true, "introspection": true}).
```

## Error signatures
- substring: `Unknown field "__schema" on type Query` (error quoted verbatim in the Supabase pg_graphql 1.6.0 changelog; opened 2026-10-29)

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0663/reports_

## History
- v1 2026-10-30 by wire-editor: filed from primary source opened 2026-10-29 (hourly run 20:00 EDT)