Merge pull request 'Issue 218: a mesh seat answered by a non-holder (located, fixed in mesh-controller#248)' (#339) from issues/218-a-mesh-seat-answered-by-a-non-holder into main

04-ISSUES/218-a-mesh-seat-is-answered-by-a-module-that-does-not-hold-it/00-report.md

@@ -1,8 +1,9 @@
 ---
-status: open
+status: located
 opened: 2026-10-03
-located-in: []
+located-in:
-fixed-by:
+  - mesh-controller
+fixed-by: mesh-controller#248
 amended-design:
 ---
 
@@ -37,3 +38,28 @@ the mesh made it the holder ([ADR 0159](../../02-DECISIONS/0159-a-tool-call-name
 [ADR 0160](../../02-DECISIONS/0160-the-mesh-issues-an-assignments-subjects-and-a-runtime-serves-what-it-is-issued.md)):
 the membership the controller issues each assignment, and what the runtime admits from it. A check:
 a mesh-scoped seat's verbs are served by exactly the holder the records name, on every machine.
+
+## Root cause
+
+The controller composed each assignment's held seats from what its module *claims*, once per module
+and not once per machine. Every machine running postgres was therefore given the store seat's grants
+and issued its subjects, and each runtime served the seat's verbs because it serves what it is issued
+([ADR 0160](../../02-DECISIONS/0160-the-mesh-issues-an-assignments-subjects-and-a-runtime-serves-what-it-is-issued.md)).
+The runtime behaved as designed. The fault was in what it was issued.
+
+The seat's verbs are not the module's tools. The store's `databases` and `query` are a separate
+implementation registered under the seat's name ([ADR 0159](../../02-DECISIONS/0159-a-tool-call-names-the-machine-and-a-holder-serves-its-seats-verbs.md)).
+Only that implementation should be withdrawn where the module does not hold the seat. postgres's own
+tools stay served on every machine it runs on.
+
+## Fix
+
+The controller now reads the recorded seat holdings when it composes grants and memberships. A seat
+held once for the mesh is issued only to the machine and module the records name as its holder. A
+seat held once per machine, and a mesh seat with no holder on record, are issued as before. Grants
+and memberships come from the same list, so they cannot disagree.
+
+**How it is checked.** A controller test asserts that a claimant on another machine keeps its node
+seats and loses the recorded mesh seat. Live, the discovery console's overview must show each
+mesh-scoped seat announced from exactly the holder the records name. Status moves to `resolved` once
+that holds after the fix is rolled out.