Merge remote-tracking branch 'origin/master' into worktree/tui-session-title-search

# Conflicts:
#	.agents/notes/implemented/feature/2026-07-21-cross-session-references.i18n.yaml
#	.agents/notes/implemented/feature/2026-07-21-cross-session-references.md
#	.agents/notes/implemented/feature/2026-07-21-cross-session-references.zh.md
#	packages/context/session-reference/README.i18n.yaml
#	packages/context/session-reference/README.md
#	packages/context/session-reference/README.zh.md
#	packages/context/session-reference/src/index.ts

packages/context/session-reference/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/context/session-reference/README.md
-README.md: 97b8b44dd0822010f64397ebd4632edbeccb6863
-README.zh.md: 921fa103e9fab0de5cdbb6ed7ef6ae863e41e3dc
+README.md: 6def2923cf3bc0021b0db578279a1b0571106d41
+README.zh.md: 9d7abfa78e6d35b2149c9436d5b397e4a30404d7

packages/context/session-reference/README.md

@@ -2,19 +2,19 @@
 
 English | [中文](README.zh.md)
 
-`ctx.sessionReferences` prepares bounded, read-only snapshots of other sessions as prompt-prefix context. It consumes `ctx.sessionQuery` and the backend-independent compact checkpoint marker; SQLite FTS is not required. The standard TUI bundle mounts it, while other hosts may call the service directly.
+`ctx.sessionReferences` prepares bounded, read-only snapshots of other sessions as sourced model-facing context. It consumes `ctx.sessionQuery` and the backend-independent compact checkpoint marker; SQLite FTS is not required. The standard TUI bundle mounts it, while other hosts may call the service directly.
 
 ## Public API
 
 - `listCandidates(agent, query?, limit?)` lists sessions other than `agent.id`, filters case-insensitively by id, cwd, or the latest log-backed title, and ranks same-cwd, cwd-less, then other-cwd records while preserving `listSessions()` creation order within each group. Each selected candidate uses that title as the mention label and falls back to the session id when the title is absent or unreadable; message bodies are not searched.
-- `prepare(agent, content, references, signal?)` preserves first-mention order, deduplicates ids, rejects self-reference and more than the configured distinct-source limit, reads every source in parallel, and returns detached content plus zero or one aggregated `HookContext`. Any invalid reference, failed read, cancellation, or budget failure rejects before the host calls `followup()` or `steer()`.
+- `prepare(agent, content, references, signal?)` preserves first-mention order, deduplicates ids, rejects self-reference and more than the configured distinct-source limit, reads every source in parallel, and returns detached content plus zero or one aggregated `UserMessageData` context. Any invalid reference, failed read, cancellation, or budget failure rejects before the host calls `followup()` or `steer()`.
 - `encodeSessionReferenceUri()` and `decodeSessionReferenceUri()` implement `dsh-session:<base64url(JSON.stringify(sessionId))>` so every JavaScript string id round-trips exactly. `formatSessionReferenceMention()` emits `@[label](uri)`, and `parseSessionReferenceText()` replaces Markdown mentions or bare canonical URIs with readable `@label` text while returning structured references. Explicit Markdown mentions reject every malformed URI; bare text is considered a reference only when a non-empty base64url-shaped payload follows the scheme, and a matching noncanonical candidate still fails. Empty or punctuation-only scheme mentions remain ordinary discussion text.
 
 ## Snapshot semantics
 
 Preparation calls `ctx.sessionQuery.readSurface()` once per distinct source and never rereads it after enqueue. It projects only direct-user `user/message`, direct-user `steering/message`, assistant text, and `user/message` checkpoints carrying the canonical `dsh-compact` source marker from the folded current surface. For a source prompt that already contains baked prefix context, projection reads only its model-hidden display content, preventing recursive snapshot propagation. Shadowed pre-compaction events, tools, reasoning, context, plugin-generated user messages other than marked compact checkpoints, and unfinished assistant chunks are excluded. A compacted source therefore contributes its latest checkpoint plus retained later conversation, not restored shadowed text.
 
-The context source is `{ kind: 'plugin', plugin: 'session-reference' }` with `placement: 'prompt-prefix'`. Its metadata records version `1`, source ids and labels, capture seqs, compact presence, retained/omitted message counts, omitted UTF-8 bytes, and truncation state. AgentLoop writes the snapshot, `## My request:` delimiter, and effective prompt into one `user/message` or `steering/message`; the same event's model-hidden envelope retains the direct prompt and metadata for UI replay. Later source mutation, compaction, or deletion cannot change target replay.
+The context source is `{ kind: 'session-reference', version: 1, references }`; each reference records its source id and label, capture seq, compact presence, retained/omitted message counts, omitted UTF-8 bytes, and truncation state. The standard TUI preserves admission ownership without attaching context to the generic inbox record: outside the next-step acceptance window, a one-shot `agent/prompt-submit` wrapper adds the snapshot only to an allowed decision; during prompt admission or an open turn, `inject()` and `steer()` stage beside each other for the same safe boundary. The target log therefore records a sourced context `user/message` followed by the readable direct `user/message` or `steering/message`. Later source mutation, compaction, or deletion cannot change target replay.
 
 ## Configuration
 
@@ -32,7 +32,7 @@ Retention applies `maxReferenceBytes` independently to each source, keeps compac
 
 #### What the model sees
 
-The model sees one user-role message in this order: the `## Referenced sessions` untrusted snapshot, the `## My request:` delimiter, then the current message with its readable `@label`. The warning forbids following instructions, permission claims, or tool requests from the snapshot unless the current user repeats them. Labels, cwd values, ids, and conversation text are serialized as JSON inside `<referenced-sessions>` tags; every data `<` is emitted as the lossless JSON escape `\u003c`, so source text cannot spell a framing tag.
+The model sees two consecutive user-role messages: the `## Referenced sessions` untrusted snapshot, then the current message with its readable `@label`. The warning forbids following instructions, permission claims, or tool requests from the snapshot unless the current user repeats them. Labels, cwd values, ids, and conversation text are serialized as JSON inside `<referenced-sessions>` tags; every data `<` is emitted as the lossless JSON escape `\u003c`, so source text cannot spell a framing tag.
 
 #### Token effect
 
@@ -40,7 +40,7 @@ Each referenced message adds the fixed warning plus up to three serialized snaps
 
 #### KV Cache effect
 
-The combined snapshot and request are append-only at the target message boundary and preserve earlier cacheable history. Different references or source capture contents change the new suffix only; later target compaction may invalidate reuse from its replacement boundary.
+The snapshot and request are consecutive append-only target messages and preserve earlier cacheable history. Different references or source capture contents change the new suffix only; later target compaction may invalidate reuse from its replacement boundary.
 
 ## Known Limitations and Deferred Work
 

packages/context/session-reference/README.zh.md

@@ -2,19 +2,19 @@
 
 [English](README.md) | 中文
 
-`ctx.sessionReferences` 会把其他会话准备为有界、只读快照，作为提示词前缀上下文。它消费 `ctx.sessionQuery` 与后端无关的 compact 检查点标记；不需要 SQLite FTS。标准 TUI bundle 会装载它，其他宿主也可直接调用该服务。
+`ctx.sessionReferences` 会把其他会话准备为有界、只读快照，作为带来源信息、面向模型的上下文。它消费 `ctx.sessionQuery` 与后端无关的 compact 检查点标记；不需要 SQLite FTS。标准 TUI bundle 会装载它，其他宿主也可直接调用该服务。
 
 ## 公开 API
 
 - `listCandidates(agent, query?, limit?)` 会列出 `agent.id` 之外的会话，按 id、cwd 或日志中最新的标题进行不区分大小写的筛选，再按同 cwd、无 cwd、其他 cwd 记录排序，同时保持每组内的 `listSessions()` 创建顺序。每个已选候选会话都使用该标题作为 mention label；标题不存在或无法读取时回退到会话 id。不搜索消息主体。
-- `prepare(agent, content, references, signal?)` 会保留首次 mention 顺序、对 id 去重，并拒绝自引用或超过已配置不同源上限的情况。它会并行读取所有源，返回与输入脱离的内容，外加零个或一个聚合 `HookContext`。任何无效引用、读取失败、取消或预算失败都会在宿主调用 `followup()` 或 `steer()` 之前被拒绝。
+- `prepare(agent, content, references, signal?)` 会保留首次 mention 顺序、对 id 去重，并拒绝自引用或超过已配置不同源上限的情况。它会并行读取所有源，返回与输入脱离的内容，外加零个或一个聚合 `UserMessageData` 上下文。任何无效引用、读取失败、取消或预算失败都会在宿主调用 `followup()` 或 `steer()` 之前被拒绝。
 - `encodeSessionReferenceUri()` 与 `decodeSessionReferenceUri()` 实现 `dsh-session:<base64url(JSON.stringify(sessionId))>`，因此每个 JavaScript 字符串 id 都能精确往返。`formatSessionReferenceMention()` 发出 `@[label](uri)`，`parseSessionReferenceText()` 将 Markdown mention 或裸规范 URI 替换为可读的 `@label` 文本，并返回结构化引用。显式 Markdown mention 会拒绝每个格式错误的 URI；只当 scheme 后跟非空、符合 base64url 形状的 payload 时，裸文本才被视为引用，匹配但非规范的候选项仍会失败。空 scheme mention 或只含标点符号的 scheme mention 仍是普通讨论文本。
 
 ## 快照语义
 
 准备阶段会对每个不同源调用一次 `ctx.sessionQuery.readSurface()`，入队后绝不重读。它仅投影折叠后当前表层中的直接 user `user/message`、直接 user `steering/message`、assistant 文本，以及 `user/message` 检查点；这类检查点携带规范 `dsh-compact` 源标记。对于已经包含烘焙前缀上下文的源提示词，投影只读取其对模型隐藏的显示内容，以防止快照递归传播。已遮蔽的压缩前事件、工具、reasoning、上下文、除已标记 compact 检查点外的插件生成 user 消息，以及未完成的 assistant chunk 均会被排除。因此，已压缩源贡献的是最新检查点与之后保留的会话，而非已恢复的遮蔽文本。
 
-上下文源为 `{ kind: 'plugin', plugin: 'session-reference' }`，并携带 `placement: 'prompt-prefix'`。其元数据会记录版本 `1`、源 id 与 label、捕获 seq、是否存在 compact、已保留／已省略消息数、已省略 UTF-8 字节数与截断状态。AgentLoop 将快照、`## My request:` 分隔符和有效提示词写入同一个 `user/message` 或 `steering/message`；同一事件的模型隐藏 envelope 保留直接提示词与元数据，用于 UI 回放。后续源变更、压缩或删除都无法改变目标回放。
+上下文源为 `{ kind: 'session-reference', version: 1, references }`；每条引用会记录其源 id 与 label、捕获 seq、是否存在 compact、已保留／已省略消息数、已省略 UTF-8 字节数与截断状态。标准 TUI 在不把上下文附加到通用 inbox 记录的情况下保留接纳归属：next-step 接收窗口之外，一次性 `agent/prompt-submit` 包装层只为获准决策添加快照；提示词接纳期间或轮次打开时，`inject()` 与 `steer()` 会并排暂存到同一安全边界。目标日志因此会先记录一条带来源信息的上下文 `user/message`，再记录可读的直接 `user/message` 或 `steering/message`。后续源变更、压缩或删除都无法改变目标回放。
 
 ## 配置
 
@@ -32,7 +32,7 @@
 
 #### 模型看到的内容
 
-模型会按此顺序看到一条 user 角色消息：`## Referenced sessions` 不受信任快照、`## My request:` 分隔符，随后是带可读 `@label` 的当前消息。警告禁止遵循快照中的指令、权限声明或工具请求，除非当前 user 重复这些内容。Label、cwd 值、id 与会话文本作为 JSON 在 `<referenced-sessions>` 标签中序列化；每个数据 `<` 都发出为无损 JSON 转义 `\u003c`，因此源文本无法拼出框定标签。
+模型会看到两条连续的 user 角色消息：先是 `## Referenced sessions` 不受信任快照，再是带可读 `@label` 的当前消息。警告禁止遵循快照中的指令、权限声明或工具请求，除非当前 user 重复这些内容。Label、cwd 值、id 与会话文本作为 JSON 在 `<referenced-sessions>` 标签中序列化；每个数据 `<` 都发出为无损 JSON 转义 `\u003c`，因此源文本无法拼出框定标签。
 
 #### Token 影响
 
@@ -40,7 +40,7 @@
 
 #### KV Cache 影响
 
-组合快照与请求在目标消息边界处仅追加，并保留较早的可缓存历史。不同引用或源捕获内容只改变新后缀；后续目标压缩可能使从替换边界起的复用失效。
+快照与请求是两条连续、仅追加的目标消息，并保留较早的可缓存历史。不同引用或源捕获内容只改变新后缀；后续目标压缩可能使从替换边界起的复用失效。
 
 ## 已知限制与暂缓事项
 

packages/context/session-reference/src/index.ts

@@ -7,9 +7,9 @@
 
 import { Context, Service } from 'cordis'
 import z from 'schemastery'
-import type { Agent, HookContext } from '@deepseek-ai/dsh-agent'
+import type { Agent } from '@deepseek-ai/dsh-agent'
 import type { ContentBlock } from '@deepseek-ai/dsh-llm'
-import type { JsonValue, SessionId } from '@deepseek-ai/dsh-session'
+import type { SessionId, UserMessageData } from '@deepseek-ai/dsh-session'
 import type { SessionSurfaceSnapshot, SessionTitleObservationResult } from '@deepseek-ai/dsh-session-query'
 import {
   DEFAULT_CANDIDATE_LIMIT,
@@ -20,7 +20,7 @@ import {
 } from './config.ts'
 import { retainReferencedSession, type ReferenceRetentionStats, type ReferencedSessionData } from './projection.ts'
 import { stringifyTagSafeJson } from './serialization.ts'
-import type { PreparedReferencedMessage, SessionReferenceCandidate, SessionReferenceInput } from './types.ts'
+import type { PreparedReferencedMessage, SessionReferenceCandidate, SessionReferenceInput, SessionReferenceSource } from './types.ts'
 
 export type * from './types.ts'
 export type { Config, SessionReferenceErrorCode } from './config.ts'
@@ -163,7 +163,7 @@ export class SessionReferenceService extends Service {
    * @param content - already host-normalized readable message content.
    * @param references - structured source sessions in mention order.
    * @param signal - optional cancellation boundary for host request teardown.
-   * @returns detached content and zero or one prepared contexts.
+   * @returns detached content and optional referenced-session context.
    */
   async prepare(
     agent: Agent,
@@ -173,7 +173,7 @@ export class SessionReferenceService extends Service {
   ): Promise<PreparedReferencedMessage> {
     const acceptedContent = structuredClone(content)
     const inputs = normalizeReferences(agent.id, references, this.config.maxReferences)
-    if (inputs.length === 0) return { content: acceptedContent, contexts: [] }
+    if (inputs.length === 0) return { content: acceptedContent }
     assertNotCancelled(signal)
     let prepared: PreparedSource[]
     try {
@@ -196,7 +196,7 @@ export class SessionReferenceService extends Service {
 
     const rendered = this.renderSources(prepared)
     const prompt = renderPrompt(rendered.map(source => source.data))
-    const meta = {
+    const source: SessionReferenceSource = {
       kind: 'session-reference',
       version: 1,
       references: rendered.map((source, index) => ({
@@ -206,14 +206,12 @@ export class SessionReferenceService extends Service {
         ...source.stats,
         inputIndex: index,
       })),
-    } satisfies JsonValue
-    const context: HookContext = {
-      source: { kind: 'plugin', plugin: 'session-reference' },
-      content: [{ type: 'text', text: prompt }],
-      placement: 'prompt-prefix',
-      meta,
     }
-    return { content: acceptedContent, contexts: [context] }
+    const additionalContext: UserMessageData = {
+      source,
+      content: [{ type: 'text', text: prompt }],
+    }
+    return { content: acceptedContent, additionalContext }
   }
 
   private renderSources(sources: readonly PreparedSource[]): RenderedSource[] {

packages/context/session-reference/src/projection.ts

@@ -1,7 +1,6 @@
 /** Current-surface projection and byte-bounded rendering. */
 
 import { isCompactCheckpointSource } from '@deepseek-ai/dsh-compact'
-import { displayPromptContent } from '@deepseek-ai/dsh-session'
 import type { SessionSurfaceSnapshot } from '@deepseek-ai/dsh-session-query'
 import { assertNever } from '@deepseek-ai/dsh-llm'
 import { TextRetainer } from '@deepseek-ai/dsh-retention'
@@ -41,13 +40,13 @@ function projectSessionConversation(snapshot: SessionSurfaceSnapshot): Projected
       case 'user/message': {
         const checkpoint = isCompactCheckpointSource(event.data.source)
         if (!checkpoint && event.data.source.kind !== 'user') break
-        const text = textContent(displayPromptContent(event.data))
+        const text = textContent(event.data.content)
         if (text !== '') conversation.push({ role: 'user', text, checkpoint, originalText: text, omittedBytes: 0 })
         break
       }
       case 'steering/message': {
         if (event.data.source.kind !== 'user') break
-        const text = textContent(displayPromptContent(event.data))
+        const text = textContent(event.data.content)
         if (text !== '') conversation.push({ role: 'user', text, checkpoint: false, originalText: text, omittedBytes: 0 })
         break
       }

packages/context/session-reference/src/types.ts

@@ -1,8 +1,31 @@
 /** Public session-reference request, candidate, and preparation records. */
 
-import type { HookContext } from '@deepseek-ai/dsh-agent'
 import type { ContentBlock } from '@deepseek-ai/dsh-llm'
-import type { SessionId } from '@deepseek-ai/dsh-session'
+import type { SessionId, UserMessageData } from '@deepseek-ai/dsh-session'
+
+/** Durable provenance for one prepared cross-session context. */
+export interface SessionReferenceSource {
+  kind: 'session-reference'
+  version: 1
+  references: {
+    sessionId: string
+    label: string
+    capturedThroughSeq: number | null
+    compacted: boolean
+    originalMessages: number
+    retainedMessages: number
+    omittedMessages: number
+    omittedBytes: number
+    truncated: boolean
+    inputIndex: number
+  }[]
+}
+
+declare module '@deepseek-ai/dsh-llm' {
+  interface MessageSourceMap {
+    'session-reference': SessionReferenceSource
+  }
+}
 
 /** One source session selected by a host. */
 export interface SessionReferenceInput {
@@ -24,12 +47,12 @@ export interface SessionReferenceCandidate {
   createdAt: number
 }
 
-/** Message payload and the zero-or-one durable snapshot contexts bound to it. */
+/** Direct message content and optional referenced-session context. */
 export interface PreparedReferencedMessage {
   /** Readable message content after host mention tokens are removed. */
   content: ContentBlock[]
-  /** Empty without references; otherwise one aggregated untrusted context. */
-  contexts: HookContext[]
+  /** Aggregated untrusted snapshot, absent when the message has no references. */
+  additionalContext?: UserMessageData
 }
 
 /** Text-only projected conversation item. */

packages/context/session-reference/tests/session-reference.spec.ts

@@ -278,11 +278,9 @@ describe('session reference discovery and preparation', () => {
       [{ sessionId: source.id, label: 'source' }],
     )
     expect(prepared.content).toEqual([{ type: 'text', text: 'use @source' }])
-    expect(prepared.contexts).toHaveLength(1)
-    const context = prepared.contexts[0]
+    const context = prepared.additionalContext
     if (context?.content[0]?.type !== 'text') throw new Error('expected text context')
-    expect(context.source).toEqual({ kind: 'plugin', plugin: 'session-reference' })
-    expect(context.placement).toBe('prompt-prefix')
+    expect(context.source).toMatchObject({ kind: 'session-reference' })
     expect(context.content[0].text).toContain('untrusted, read-only snapshot')
     expect(promptData(context.content[0].text)).toEqual([{
       sessionId: 'source',
@@ -296,7 +294,7 @@ describe('session reference discovery and preparation', () => {
         { role: 'assistant', text: 'visible answer' },
       ],
     }])
-    expect(context.meta).toMatchObject({
+    expect(context.source).toMatchObject({
       kind: 'session-reference',
       version: 1,
       references: [{
@@ -316,21 +314,17 @@ describe('session reference discovery and preparation', () => {
     expect(context.content[0].text).not.toContain('later source mutation')
   })
 
-  it('projects only the direct prompt when a source message contains baked prefix context', async () => {
+  it('excludes injected context when projecting a referenced session', async () => {
     const ctx = await harness()
     const target = ctx.sessions.create(SessionId('target'))
     const source = ctx.sessions.create(SessionId('source'))
     source.append('user/message', {
-      content: [
-        { type: 'text', text: 'nested referenced snapshot must not propagate' },
-        { type: 'text', text: '\n\n## My request:\n' },
-        { type: 'text', text: 'direct source question' },
-      ],
+      content: [{ type: 'text', text: 'nested referenced snapshot must not propagate' }],
+      source: { kind: 'plugin', plugin: 'session-reference' },
+    }, { surfaceOp: 'append' })
+    source.append('user/message', {
+      content: [{ type: 'text', text: 'direct source question' }],
       source: { kind: 'user' },
-      envelope: {
-        displayContent: [{ type: 'text', text: 'direct source question' }],
-        prefixContexts: [{ source: { kind: 'plugin', plugin: 'session-reference' } }],
-      },
     }, { surfaceOp: 'append' })
 
     const prepared = await ctx.sessionReferences.prepare(
@@ -338,7 +332,7 @@ describe('session reference discovery and preparation', () => {
       [{ type: 'text', text: 'inspect source' }],
       [{ sessionId: source.id }],
     )
-    const context = prepared.contexts[0]
+    const context = prepared.additionalContext
     if (context?.content[0]?.type !== 'text') throw new Error('expected text context')
     expect(promptData(context.content[0].text)).toMatchObject([{
       conversation: [{ role: 'user', text: 'direct source question' }],
@@ -362,7 +356,7 @@ describe('session reference discovery and preparation', () => {
       [{ type: 'text', text: 'use @source' }],
       [{ sessionId: source.id }],
     )
-    const context = prepared.contexts[0]
+    const context = prepared.additionalContext
     if (context?.content[0]?.type !== 'text') throw new Error('expected text context')
     const prompt = context.content[0].text
     expect(prompt).toMatch(/^## Referenced sessions\n/u)
@@ -387,14 +381,14 @@ describe('session reference discovery and preparation', () => {
     const content = [{ type: 'text' as const, text: 'go' }]
 
     const withoutReferences = await ctx.sessionReferences.prepare(agent, content, [])
-    expect(withoutReferences).toEqual({ content, contexts: [] })
+    expect(withoutReferences).toEqual({ content })
     expect(withoutReferences.content).not.toBe(content)
 
     await expect(ctx.sessionReferences.prepare(agent, content, [
       { sessionId: one.id, label: 'first' },
       { sessionId: one.id, label: 'ignored duplicate' },
       { sessionId: two.id },
-    ])).resolves.toMatchObject({ contexts: [{ meta: { references: [{ label: 'first' }, { label: 'two' }] } }] })
+    ])).resolves.toMatchObject({ additionalContext: { source: { references: [{ label: 'first' }, { label: 'two' }] } } })
     await expect(ctx.sessionReferences.prepare(agent, content, [{ sessionId: target.id }]))
       .rejects.toThrow(expectCode('SESSION_REFERENCE_SELF_REFERENCE'))
     await expect(ctx.sessionReferences.prepare(agent, content, [null as never]))
@@ -465,14 +459,14 @@ describe('session reference discovery and preparation', () => {
     )
 
     const prepared = await ctx.sessionReferences.prepare(fakeAgent(target), [{ type: 'text', text: 'go' }], [{ sessionId: source.id }])
-    const context = prepared.contexts[0]
+    const context = prepared.additionalContext
     if (context?.content[0]?.type !== 'text') throw new Error('expected text context')
     const data = promptData(context.content[0].text) as unknown[]
     expect(Buffer.byteLength(stringifyTagSafeJson(data[0]), 'utf8')).toBeLessThanOrEqual(360)
     expect(context.content[0].text).toContain('checkpoint')
     expect(context.content[0].text).toContain('latest-')
     expect(context.content[0].text).toContain('omitted')
-    expect(context.meta).toMatchObject({ references: [{ truncated: true, compacted: true }] })
+    expect(context.source).toMatchObject({ references: [{ truncated: true, compacted: true }] })
   })
 
   it('applies the full byte limit independently to each of three references', async () => {
@@ -499,7 +493,7 @@ describe('session reference discovery and preparation', () => {
       [{ type: 'text', text: 'go' }],
       sources.map(source => ({ sessionId: source.id })),
     )
-    const context = prepared.contexts[0]
+    const context = prepared.additionalContext
     if (context?.content[0]?.type !== 'text') throw new Error('expected text context')
     const data = promptData(context.content[0].text) as unknown[]
     const sizes = data.map(source => Buffer.byteLength(stringifyTagSafeJson(source), 'utf8'))
@@ -532,18 +526,12 @@ describe('session reference discovery and preparation', () => {
       [{ type: 'text', text: 'use @source' }],
       [{ sessionId: source.id }],
     )
-    const context = prepared.contexts[0]
+    const context = prepared.additionalContext
     if (context === undefined) throw new Error('expected prepared context')
+    target.append('user/message', context, { surfaceOp: 'append' })
     target.append('user/message', {
-      content: [...context.content, { type: 'text', text: '\n\n## My request:\n' }, ...prepared.content],
+      content: prepared.content,
       source: { kind: 'user' },
-      envelope: {
-        displayContent: prepared.content,
-        prefixContexts: [{
-          source: context.source,
-          ...context.meta === undefined ? {} : { meta: context.meta },
-        }],
-      },
     }, { surfaceOp: 'append' })
     const before = target.deriveMessages()
 
@@ -570,7 +558,7 @@ describe('session reference discovery and preparation', () => {
     expect(ctx.sessions.get(source.id)).toBeUndefined()
     expect(target.deriveMessages()).toEqual(before)
     expect(JSON.stringify(before)).toContain('durable referenced fact')
-    expect(JSON.stringify(before)).toContain('## My request:')
+    expect(JSON.stringify(before)).toContain('use @source')
     expect(JSON.stringify(before)).not.toContain('later source mutation')
     expect(new Session(SessionId('replayed-target'), target.events).deriveMessages()).toEqual(before)
   })