From ae0b6c6e57929bf2b6bfe91eaede0639a91d262a Mon Sep 17 00:00:00 2001
From: Ricky Schema Cascade <ricky@agent-relay.com>
Date: Wed, 10 Jun 2026 09:13:06 +0200
Subject: [PATCH] fix(runtime): no-trigger personas narrow to AgentEvent, not
 BaseAgentEvent

v4.0.0 regression: defineAgent's event narrowing collapsed personas that declare
no concrete trigger literals (e.g. team members launched by a dispatcher) to
`BaseAgentEvent<`${string}.${string}`>`, which is narrower than `AgentEvent` and
rejects an `(event: AgentEvent)`/`WorkforceEvent` handler:

  Type '(ctx, event: WorkforceEvent) => ...' is not assignable to
  '(ctx, event: ProviderEventFor<string, string>) => ...'

ProviderEventFor now falls back to the full `AgentEvent` when the trigger `on`
union is the wide `string` (nothing concrete declared), while still mapping
declared literals to `BaseAgentEvent<`${P}.${O}`>` (incl. 2-segment types like
slack.app_mention). Restores the pre-v4 behavior for trigger-less personas.

86 runtime tests pass; the agents repo's cloud-team member personas typecheck
clean against the rebuilt runtime.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 packages/runtime/src/define-agent.ts | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/packages/runtime/src/define-agent.ts b/packages/runtime/src/define-agent.ts
index f864d18d..72fd7cee 100644
--- a/packages/runtime/src/define-agent.ts
+++ b/packages/runtime/src/define-agent.ts
@@ -39,7 +39,15 @@ type TriggerOnUnion<Tr> = OnLiteralsOf<NonNullable<Tr[keyof Tr]>>;
 // for any provider event shape — including 2-segment types like
 // `slack.app_mention` that aren't valid `EventType`s (those collapse to `never`
 // under `AgentEvent<...>`).
-type ProviderEventFor<P extends string, O extends string> = BaseAgentEvent<`${P}.${O}`>;
+//
+// When `O` is the wide `string` (a persona that declares no concrete trigger
+// literals — e.g. team members launched by a dispatcher), fall back to the full
+// `AgentEvent` so a `(event: AgentEvent)` handler stays assignable. Without this
+// the wide case narrows to `BaseAgentEvent<\`${string}.${string}\`>`, which is
+// narrower than `AgentEvent` and rejects an `AgentEvent`-typed handler.
+type ProviderEventFor<P extends string, O extends string> = string extends O
+  ? AgentEvent
+  : BaseAgentEvent<`${P}.${O}`>;
 
 type TriggerProviderEvents<Tr> = {
   [P in keyof Tr]: P extends string