feat(ai-harness, ai-mcp, ai-acp, ai-code-mode, ai-harness-cli): the final review of the harness, with its fixes, one object per call, and the known limits

.changeset/ai-harness-coding-tools.md

@@ -5,15 +5,15 @@
 Add coding tools in the new Node entry `@tanstack/ai-harness/plugins/coding`:
 
 - `workspaceTools({ root })` gives `read_file` (text pages, images, PDFs), `write_file`, `edit_file` or `patch` (`editStyle`), `list_files`, `grep`, `bash` (with `background`), `webfetch`, and `websearch` (with a `SearchProvider`). With `permissions()`, edits, `bash`, and `webfetch` ask first, and the rules also apply to the real path of a link. `outside: 'ask'` makes a path outside `root` need an approval. `permissions()` decides outside paths and the real paths of links before the call runs, so a tool never asks while it runs. The `cwd` thread setting gives each thread its own working folder.
-- `workspaceTools({ workspace: { bind, reattach? } })` gives each thread its own workspace. The root of the workspace is the boundary of every tool. The session log keeps where the workspace is (`harness.workspace.bound`). On another host, `reattach` gives the workspace back (for example a resumed sandbox), or `'pinned'` or `'gone'`. A gone workspace sends `tanstack/workspace-tools:stranded`.
+- `workspaceTools({ workspace: { bind, reattach? } })` gives each thread its own workspace. The root of the workspace is the boundary of every tool. The session log keeps where the workspace is (`harness.workspace.bound`). On another host, `reattach` gives the workspace back (for example a resumed sandbox), or `'pinned'` or `'gone'`. A gone workspace sends `tanstack/workspace-tools:stranded`. With this plugin first, `snapshots()` and `formatter()` use the workspace of each thread, and their `root` is optional.
 - `createHarnessHost({ ownership: { hostId } })` gives a host a stable id. Then a thread that uses a folder on that host is pinned to it, and other hosts refuse its tool calls. Without `hostId`, threads are not pinned.
 - Commands, `rg`, `git`, and the formatters get only a short list of variables of the server process, plus the `env` of the backend call. Git runs without the hooks and the `fsmonitor` of the project.
 - The tools resolve links with `realpath` under the file lock, and fail when a backend cannot resolve a path. A write fails when the file changed after the tool read it. The file locks are shared by the sessions of a host.
-- Background jobs: at most 8 per session (`maxJobs`), the newest 1 MiB of output per job, and the events `tanstack/workspace-tools:job-started`, `job-output`, and `job-ended`. A job that an earlier host left running is stopped at the next tool call, with a note to the model.
+- Background jobs: at most 8 per session (`maxJobs`), the newest 1 MiB of output per job, and the events `tanstack/workspace-tools:job-started`, `job-output`, and `job-ended`. A job that an earlier host left running is stopped at the next tool call, with a note to the model. The wake turn of a job runs as the user who started it. The `bash` spill file has `[redacted]` in place of each secret of the session.
 - `read_file` sends images and PDFs up to 256 KB. `webfetch` gives the model the first 256 KB of a page.
 - A `WorkspaceBackend` runs the tools. `hostBackend` is the default. `realpath` is required. `spawn` can give a `jobId`, and `killJob`, `binding`, and `close` are optional. On Windows, commands do not run a program from the working folder by its name.
-- `snapshots()` adds `/undo` and `/redo`, which restore only the files of the turn (git 2.26 or newer), file restore for `session.revert()`, and a diff for each model step. Each thread of each tenant has its own shadow repository, which never stores `.env` files. A step keeps only the files of its own run. The steps and the undo point are in the session log, so another host with the same repository can undo. A revert uses the last 500 steps. `purgeSnapshots()` removes the repository of a thread. A failed snapshot sends `tanstack/snapshots:failed`.
-- `formatter()` formats each written file with the formatter of the project. With `permissions()`, the rules decide the formatter with the call that writes, before that call runs: one approval covers both, and the formatter runs after the write.
+- `snapshots()` adds `/undo` and `/redo`, which restore only the files of the turn (git 2.26 or newer), file restore for `session.revert()`, and a diff for each model step. Each thread of each tenant has its own shadow repository, which never stores `.env` files. A step keeps only the files of its own run. The steps and the undo point are in the session log, so another host with the same repository can undo. A revert uses the last 500 steps. `host.sessions.delete` removes the repository of the thread, and `purgeSnapshots()` does it from your own code. A failed snapshot sends `tanstack/snapshots:failed`.
+- `formatter()` formats each written file with the formatter of the project. With `permissions()`, the rules decide the formatter with the call that writes, before that call runs: one approval covers both, and the formatter runs after the write. An `always` answer is tied to a hash of the formatter config files. A write of a formatter config below the root, or under `node_modules`, asks each time, and an `always` answer saves no rule for that formatter run.
 - `WorkspaceHooks` lets other plugins run code after a read or a write.
 
 `@vscode/ripgrep` and `turndown` are optional peer dependencies.