diff --git a/examples/acp-agent/composition.md b/examples/acp-agent/composition.md
index 6cd896ca31..b4a3236920 100644
--- a/examples/acp-agent/composition.md
+++ b/examples/acp-agent/composition.md
@@ -94,4 +94,4 @@ flowchart LR
 
 Source config: [`examples/acp-agent/cordis.yml`](cordis.yml).
 
-Maintenance mode: hybrid: the leaf plugin list is parsed from its shipped config files; app package expansion is curated from package source.
+Maintenance mode: hybrid: the leaf plugin list is parsed from its `cordis.yml`; app package expansion is curated from package source.
diff --git a/packages/support/acp-snapshot/src/harness.ts b/packages/support/acp-snapshot/src/harness.ts
index 56df34e80f..d11a4f1b9c 100644
--- a/packages/support/acp-snapshot/src/harness.ts
+++ b/packages/support/acp-snapshot/src/harness.ts
@@ -155,13 +155,6 @@ export interface RunOptions {
    * start from an empty workspace.
    */
   workspaceDir?: string
-  /**
-   * Optional setup run in the generated cwd after {@link workspaceDir} is
-   * copied and before the child boots — for world state a committed fixture
-   * cannot express, such as a `.git` entry (git never tracks that name, so a
-   * repository-shaped fixture has to be materialized at run time).
-   */
-  prepareCwd?: (cwd: string) => Promise<void>
   /**
    * Parent directory for the generated session cwd. Defaults to
    * `os.tmpdir()`. A scenario that must distinguish its workspace from the
@@ -228,7 +221,6 @@ export async function runScenario(input: InputScript, opts: RunOptions): Promise
     if (opts.workspaceDir !== undefined && existsSync(opts.workspaceDir)) {
       await cp(opts.workspaceDir, cwd, { recursive: true })
     }
-    await opts.prepareCwd?.(cwd)
     const env: NodeJS.ProcessEnv = {
       ...opts.env,
       DSH_SNAPSHOT: opts.mode,
diff --git a/packages/support/acp-snapshot/src/suite.ts b/packages/support/acp-snapshot/src/suite.ts
index efc1165c45..d04a481993 100644
--- a/packages/support/acp-snapshot/src/suite.ts
+++ b/packages/support/acp-snapshot/src/suite.ts
@@ -130,12 +130,6 @@ export interface Scenario {
    * test and the scenario needs an independent project location.
    */
   workspaceParent?: string
-  /**
-   * Setup run in the generated cwd after the `workspace/` fixture is copied and
-   * before the child boots, for world state a committed fixture cannot express
-   * — a `.git` entry, which git never tracks under that name.
-   */
-  prepareCwd?: (cwd: string) => Promise<void>
   /**
    * Whether Windows additionally compares stdout with native separators against
    * `stdout.expected.windows.jsonl`. The shared canonical stdout expected output is still
@@ -987,7 +981,6 @@ export function defineAcpSnapshotSuite(options: SnapshotSuiteOptions): void {
           ...!RECORDING && childFixtureFiles.length > 0 ? { childFiles: childFixtureFiles.map(file => join(dir, file)) } : {},
           ...existsSync(workspaceDir) ? { workspaceDir } : {},
           ...scenario.workspaceParent !== undefined ? { workspaceParent: scenario.workspaceParent } : {},
-          ...scenario.prepareCwd !== undefined ? { prepareCwd: scenario.prepareCwd } : {},
           // A scenario booting an overlay tree passes its own live config; the
           // bin's replay swap derives the sibling `*cordis.snapshot.yml` from it.
           ...scenario.configPath !== undefined ? { configPath: scenario.configPath } : {},
diff --git a/packages/support/acp-snapshot/tests/fixtures/suite/plain-turn/stdout.expected.jsonl b/packages/support/acp-snapshot/tests/fixtures/suite/plain-turn/stdout.expected.jsonl
index bed4c47530..d0242ae39f 100644
--- a/packages/support/acp-snapshot/tests/fixtures/suite/plain-turn/stdout.expected.jsonl
+++ b/packages/support/acp-snapshot/tests/fixtures/suite/plain-turn/stdout.expected.jsonl
@@ -1,5 +1,5 @@
 {"jsonrpc":"2.0","id":1,"result":{"protocolVersion":1,"agentCapabilities":{"loadSession":false}}}
 {"jsonrpc":"2.0","id":2,"result":{"sessionId":"{{sessionId}}"}}
 {"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_message_chunk","content":{"type":"text","text":"thinking about it"}}}}
-{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_message_chunk","content":{"type":"text","text":"workspace:prepared.marker,seed.txt"}}}}
+{"jsonrpc":"2.0","method":"session/update","params":{"sessionId":"{{sessionId}}","update":{"sessionUpdate":"agent_message_chunk","content":{"type":"text","text":"workspace:seed.txt"}}}}
 {"jsonrpc":"2.0","id":3,"result":{"stopReason":"end_turn"}}
diff --git a/packages/support/acp-snapshot/tests/suite.spec.ts b/packages/support/acp-snapshot/tests/suite.spec.ts
index a8dec942ae..420dcef2cf 100644
--- a/packages/support/acp-snapshot/tests/suite.spec.ts
+++ b/packages/support/acp-snapshot/tests/suite.spec.ts
@@ -1,5 +1,5 @@
 import { cpSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from 'node:fs'
-import { rm, writeFile } from 'node:fs/promises'
+import { rm } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { fileURLToPath } from 'node:url'
@@ -78,7 +78,6 @@ const REPLAY_SCENARIOS: Scenario[] = [
     env: { DSH_PERMISSION_MODE: 'never' },
     configPath: AGENT.configPath,
     workspaceParent: tmpdir(),
-    prepareCwd: async (cwd) => { await writeFile(join(cwd, 'prepared.marker'), 'prepared\n') },
   },
   { name: 'no-model', hasModelTurn: false, recorded: false, headerClass: 'main' },
   { name: 'blocked-log', hasModelTurn: false, comparesLog: true, recorded: false, headerClass: 'main' },