refactor(agent): unify sourced message delivery

examples/headless-agent/tests/code-mode.e2e.ts

@@ -311,12 +311,12 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('Code Mode: real model writes a p
     ctx = await codeModeHarness(workdir)
     const agent = ctx.agentLoop.create(SessionId('e2e-code-mode'), { provider: 'deepseek', model: 'deepseek-v4-flash' })
 
-    agent.followup([{
+    agent.followup({ content: [{
       type: 'text',
       text: 'Using one run_code program: run `echo alpha-7` with the bash tool, run `echo beta-9` with the bash tool, '
         + 'then write both outputs joined by a plus sign into combined.txt (bash heredoc or redirect), '
         + 'and return only the joined string.',
-    }])
+    }], source: { kind: 'user' } })
     await waitForIdle(ctx, agent)
     const events: SessionEvent[] = [...agent.session.events]
 
@@ -363,10 +363,10 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('Code Mode: real model writes a p
       agentOptions: { provider: 'deepseek', model: 'deepseek-v4-flash' },
     })
 
-    handle.agent.followup([{
+    handle.agent.followup({ content: [{
       type: 'text',
       text: 'Use one run_code program to call tools.read on pkg/deep/task.txt. After it finishes, answer: Code Mode workspace handshake?',
-    }])
+    }], source: { kind: 'user' } })
     await waitForIdle(ctx, handle.agent)
 
     const events: SessionEvent[] = [...handle.agent.session.events]

examples/headless-agent/tests/coding-task.e2e.ts

@@ -56,12 +56,12 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('coding task: fix a failing test
     ctx = await codingHarness(workdir, { persona: SYSTEM_PROMPT })
     const agent = ctx.agentLoop.create(SessionId('e2e-task'), { provider: 'deepseek', model: 'deepseek-v4-flash' })
 
-    agent.followup([{
+    agent.followup({ content: [{
       type: 'text',
       text: 'In the current directory, `node add.test.js` fails because add.js has a bug. '
         + 'Fix add.js so the test passes, run `node add.test.js` to verify, and report the result. '
         + 'Do not modify add.test.js.',
-    }])
+    }], source: { kind: 'user' } })
     await waitForIdle(ctx, agent)
 
     // The agent claims success…

examples/headless-agent/tests/compaction.e2e.ts

@@ -46,12 +46,12 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('compaction: a long session compa
     })
     const agent = ctx.agentLoop.create(SessionId('e2e-compaction'), { provider: 'deepseek', model: 'deepseek-v4-flash' })
 
-    agent.followup([{
+    agent.followup({ content: [{
       type: 'text',
       text: 'Read file1.txt, file2.txt, file3.txt, and file4.txt one at a '
         + 'time using cat (a separate bash command for each). After reading all four, tell me how '
         + 'many files you read and the number mentioned in file1.txt.',
-    }])
+    }], source: { kind: 'user' } })
     await waitForIdle(ctx, agent)
 
     const events = [...agent.session.events]

examples/headless-agent/tests/full-loop.e2e.ts

@@ -30,7 +30,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('full loop: real model + real bas
     ctx = await codingHarness(workdir, { persona: SYSTEM_PROMPT })
     const agent = ctx.agentLoop.create(SessionId('e2e-loop'), { provider: 'deepseek', model: 'deepseek-v4-flash' })
 
-    agent.followup([{ type: 'text', text: 'Run `echo e2e-ok` with the bash tool and tell me its exact output.' }])
+    agent.followup({ content: [{ type: 'text', text: 'Run `echo e2e-ok` with the bash tool and tell me its exact output.' }], source: { kind: 'user' } })
     await waitForIdle(ctx, agent)
 
     const events = [...agent.session.events]

examples/headless-agent/tests/resume.e2e.ts

@@ -41,7 +41,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('resume: continue a persisted ses
       sessionId: SESSION_ID,
       agentOptions: { provider: 'deepseek', model: 'deepseek-v4-flash' },
     })).agent
-    first.followup([{ type: 'text', text: `Remember this code for later: ${SECRET}. Just acknowledge it.` }])
+    first.followup({ content: [{ type: 'text', text: `Remember this code for later: ${SECRET}. Just acknowledge it.` }], source: { kind: 'user' } })
     await waitForIdle(ctx, first)
     await ctx.fiber.dispose()
     ctx = undefined
@@ -58,7 +58,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('resume: continue a persisted ses
     // The prior user turn is in the rehydrated log before the model is asked.
     expect(JSON.stringify(resumed.session.deriveMessages())).toContain(SECRET)
 
-    resumed.followup([{ type: 'text', text: 'What was the code I asked you to remember? Reply with just the code.' }])
+    resumed.followup({ content: [{ type: 'text', text: 'What was the code I asked you to remember? Reply with just the code.' }], source: { kind: 'user' } })
     await waitForIdle(ctx, resumed)
 
     // The model recalls it — only possible from the resumed history.

examples/headless-agent/tests/todo-write.e2e.ts

@@ -28,10 +28,10 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('todo_write: real model records a
     ctx = await codingHarness(workdir, { persona: TODO_SYSTEM_PROMPT })
     const agent = ctx.agentLoop.create(SessionId('e2e-todo'), { provider: 'deepseek', model: 'deepseek-v4-flash' })
 
-    agent.followup([{ type: 'text', text:
+    agent.followup({ content: [{ type: 'text', text:
       'Use the todo_write tool to record a plan of exactly two steps: first '
       + '"inspect the failing test" (in_progress), then "apply the fix" (pending). '
-      + 'Send both in one todo_write call, then reply with the single word DONE.' }])
+      + 'Send both in one todo_write call, then reply with the single word DONE.' }], source: { kind: 'user' } })
     await waitForIdle(ctx, agent)
 
     const events = [...agent.session.events]