Fix workspace context review findings

packages/core/agent-loop/README.md

@@ -59,7 +59,7 @@ forever:
   TURN (error-contained):
     'turn/start'
     each queued: waterfall agent/prompt-submit → allow (→ session('user/message'),
-      inject additionalContext) | block (→ session('prompt/blocked'), drop)
+      inject each additionalContexts entry) | block (→ session('prompt/blocked'), drop)
     if every prompt blocked: 'turn/end'(rejected), no step  ⟵ zero-step turn
     STEP loop:
       drain steering

packages/core/agent-loop/src/loop.ts

@@ -155,7 +155,7 @@ export interface LoopHandle {
  *   wait for queued messages (idle)
  *   TURN (error-contained — a throwing plugin ends the turn, never the loop):
  *     'turn/start'; each queued msg: waterfall agent/prompt-submit    ⟵ durable turn boundary (no agent/* mirror)
- *       allow → session('user/message'…) (+ inject additionalContext) | block → drop
+ *       allow → session('user/message'…) (+ inject additionalContexts) | block → drop
  *     every prompt blocked → 'turn/end'(rejected), 0 steps
  *     STEP loop:
  *       drain steering → session('steering/message')  ⟵ catches late steering
@@ -406,13 +406,14 @@ async function runTurn(
       // `allow.content` REPLACES the prompt bytes (a rewrite); absent keeps them.
       const content = decision.content ?? message.content
       session.append('user/message', { content, source: message.source }, { surfaceOp: 'append' })
-      // `allow.additionalContext` is a SEPARATE context/message the next request
-      // also sees. The turn is open, so inject() appends it into THIS turn.
-      if (decision.additionalContext) {
-        agent.inject(decision.additionalContext.content, {
-          source: decision.additionalContext.source,
-          ...decision.additionalContext.envelope !== undefined ? { envelope: decision.additionalContext.envelope } : {},
-          ...decision.additionalContext.meta !== undefined ? { meta: decision.additionalContext.meta } : {},
+      // Every `allow.additionalContexts` entry is a separate context/message the
+      // next request also sees. The turn is open, so inject() appends each one
+      // into THIS turn without flattening provenance, framing, or metadata.
+      for (const context of decision.additionalContexts ?? []) {
+        agent.inject(context.content, {
+          source: context.source,
+          ...context.envelope !== undefined ? { envelope: context.envelope } : {},
+          ...context.meta !== undefined ? { meta: context.meta } : {},
         })
       }
     }

packages/core/agent-loop/tests/interception.spec.ts

@@ -17,7 +17,7 @@ import { MockAdapter, textResponse, toolCallResponse } from './mock-adapter.ts'
  * The interception seams introduced by the hooks taxonomy: `agent/prompt-submit`,
  * `agent/session-start`, the reshaped `agent/turn-continuation`
  * ({@link ContinuationDecision}), and the `tools/pre-execute` / `tools/post-execute`
- * split with `additionalContext` buffering. These verify the canonical event
+ * split with `additionalContexts` buffering. These verify the canonical event
  * surface a hook bridge (or a native plugin) programs against, WITHOUT any
  * external protocol — a native plugin uses the typed decisions directly.
  */
@@ -91,7 +91,7 @@ describe('agent/prompt-submit', () => {
     expect(JSON.stringify(adapter.requests[0]!.messages)).not.toContain('original')
   })
 
-  it('allow with additionalContext injects a separate context/message into the turn', async () => {
+  it('allow with additionalContexts injects separate context/message events into the turn', async () => {
     const adapter = new MockAdapter([textResponse('ok')])
     const ctx = await harness(adapter)
     const agent = ctx.agentLoop.create(AgentId('a1'), { model: 'mock' })
@@ -100,12 +100,12 @@ describe('agent/prompt-submit', () => {
     ctx.on('agent/prompt-submit', async (): Promise<PromptDecision> =>
       ({
         kind: 'allow',
-        additionalContext: {
+        additionalContexts: [{
           content: [{ type: 'text', text: '<system-reminder>extra ctx</system-reminder>' }],
           source: { kind: 'plugin', plugin: 'test' },
           envelope: 'raw',
           meta,
-        },
+        }],
       }))
 
     send(agent, 'go')
@@ -124,7 +124,7 @@ describe('agent/prompt-submit', () => {
     expect(sent).toContain('extra ctx')
   })
 
-  it('a prompt-submit rewrite + additionalContext is VISIBLE to the agent/pre-step seam (merged ordering)', async () => {
+  it('a prompt-submit rewrite + additionalContexts is VISIBLE to the agent/pre-step seam (merged ordering)', async () => {
     // The merge of the interception seams with master's compaction seam pins one
     // ordering: `agent/prompt-submit` runs (rewriting the prompt and injecting
     // context) BEFORE the step loop, and `agent/pre-step` fires INSIDE the step
@@ -141,7 +141,7 @@ describe('agent/prompt-submit', () => {
       ({
         kind: 'allow',
         content: [{ type: 'text', text: 'REWRITTEN prompt' }],
-        additionalContext: { content: [{ type: 'text', text: 'injected ctx' }], source: { kind: 'plugin', plugin: 'test' } },
+        additionalContexts: [{ content: [{ type: 'text', text: 'injected ctx' }], source: { kind: 'plugin', plugin: 'test' } }],
       }))
 
     // The pre-step seam (where compaction lives) derives the surface it would act