fix(workspace-context): escape instruction metadata

packages/support/acp-snapshot/src/harness.ts

@@ -155,6 +155,13 @@ export interface RunOptions {
    * start from an empty workspace.
    */
   workspaceDir?: string
+  /**
+   * Optional final workspace preparation, run after {@link workspaceDir} is
+   * copied and before the agent starts. This is for fixtures that cannot be
+   * represented portably in Git (for example, a POSIX-only filename that is
+   * invalid on Windows); ordinary seeded files belong in `workspaceDir`.
+   */
+  prepareWorkspace?: (cwd: string) => void | Promise<void>
   /**
    * Parent directory for the generated session cwd. Defaults to
    * `os.tmpdir()`. A scenario that must distinguish its workspace from the
@@ -221,6 +228,7 @@ 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.prepareWorkspace?.(cwd)
     const env: NodeJS.ProcessEnv = {
       ...opts.env,
       DSH_SNAPSHOT: opts.mode,

packages/support/acp-snapshot/src/suite.ts

@@ -114,6 +114,12 @@ export interface Scenario {
    * test and the scenario needs an independent project location.
    */
   workspaceParent?: string
+  /**
+   * Optional final workspace preparation after the committed fixture is
+   * copied. Reserve this for paths that Git cannot represent portably; normal
+   * scenario files belong under the scenario's `workspace/` directory.
+   */
+  prepareWorkspace?: (cwd: string) => void | Promise<void>
   /**
    * Whether Windows additionally compares stdout with native separators against
    * `stdout.expected.windows.jsonl`. The shared canonical stdout expected output is still
@@ -849,6 +855,7 @@ export function defineAcpSnapshotSuite(options: SnapshotSuiteOptions): void {
           // replays from its own script. In RECORD they are harvested, not read.
           ...!RECORDING && childFixtureFiles.length > 0 ? { childFiles: childFixtureFiles.map(file => join(dir, file)) } : {},
           ...existsSync(workspaceDir) ? { workspaceDir } : {},
+          ...scenario.prepareWorkspace !== undefined ? { prepareWorkspace: scenario.prepareWorkspace } : {},
           ...scenario.workspaceParent !== undefined ? { workspaceParent: scenario.workspaceParent } : {},
           // A scenario booting an overlay tree passes its own live config; the
           // bin's replay swap derives the sibling `*cordis.snapshot.yml` from it.