Closes
[CODAGT-317](https://linear.app/codercom/issue/CODAGT-317/pr-workspaces-sometimes-require-name-confirmation-to-delete).
## Problem
The `/agents` archive-and-delete molly-guard (typing the workspace name)
was firing for chats that had clearly created their own workspace. The
heuristic in `resolveArchiveAndDeleteAction` decides whether
confirmation is needed by comparing the workspace's `created_at` against
the chat's `created_at`:
```ts
return new Date(workspaceCreatedAt) >= new Date(chatCreatedAt);
```
That assumption breaks for **prebuilt workspaces**.
`ClaimPrebuiltWorkspace` rewrites `owner_id`, `name`, `updated_at`,
`last_used_at`, etc., but **never touches `created_at`**, which still
reflects when the prebuild was provisioned by the reconciler, often
hours before the chat exists. Result: every prebuild-claimed workspace
looks pre-existing, so the molly-guard fires.
Concrete example from a real chat:
| Field | Value |
|---|---|
| `chat.created_at` | `2026-05-07T15:12:23Z` |
| `workspace.created_at` (provision) | `2026-05-07T14:22:24Z` |
| `latest_build.created_at` (claim) | `2026-05-07T15:19:09Z` |
`14:22:24 < 15:12:23` so `isWorkspaceAutoCreated` returned false even
though the chat issued the claim.
## Fix (frontend-only)
Derive the moment a workspace was acquired from existing build history
rather than relying on `workspace.created_at`:
- Build #1 initiator = prebuilds system user → workspace was a prebuild
→ use `build_2.created_at` (the claim build) as the acquisition time.
- Build #1 initiator = real user → workspace was created from scratch →
use `workspace.created_at` (unchanged behavior).
- Unclaimed prebuild or no build history → return `null` (force
confirmation; safe degradation for a destructive flow).
The resolver fetches the build list via the existing
`getWorkspaceBuilds` endpoint when the dialog might fire. No new column,
no migration, no schema change. Works retroactively for all existing
claimed prebuilds; no backfill needed.
The prebuilds system user UUID is exposed via
`codersdk.PrebuildsSystemUserID` and typegen'd to `typesGenerated.ts`.
`coderd/database.PrebuildsSystemUserID` parses that constant via
`uuid.MustParse` so the two cannot drift; if the codersdk literal ever
changes, package init fails fast.
## History
The first draft of this PR added a `workspaces.claimed_at` column
populated by `ClaimPrebuiltWorkspace`. After review feedback from
@johnstcn pointing out that the same fact is already implicit in build
history, I pivoted to the frontend-only approach. Subsequent review
notes consolidated the prebuilds system user UUID into a single
typegen'd constant.
## Why not the other open PRs
- **#25055** (`chatKey` cache fallback) only fixes a different
cache-miss path; it explicitly notes it does not address `created_at <
chat.created_at`.
- **#25053** (`chats.workspace_auto_created` boolean) puts the truth on
the wrong side of the schema: "this workspace was claimed at time T" is
a property of the workspace, not the chat. The MCP plumbing it adds is
also unnecessary now that the same answer is available from build
history.
## Test plan
- `pnpm vitest run --project=unit
src/pages/AgentsPage/utils/agentWorkspaceUtils.test.ts` — 40/40 pass;
new cases cover prebuild claim before/after chat, unclaimed prebuild,
missing-build-history fallback, and the fetch-skip when the chat is not
in cache.
- `pnpm lint:types`, `pnpm check`, `make pre-commit`.
<details>
<summary>Disclosure</summary>
Opened on behalf of @kylecarbs by [Coder
Agents](https://coder.com/coder-agents).
</details>
## Description
This PR adds support for deleting prebuilt workspaces via the
authorization layer. It introduces special-case handling to ensure that
`prebuilt_workspace` permissions are evaluated when attempting to delete
a prebuilt workspace, falling back to the standard `workspace` resource
as needed.
Prebuilt workspaces are a subset of workspaces, identified by having
`owner_id` set to `PREBUILD_SYSTEM_USER`.
This means:
* A user with `prebuilt_workspace.delete` permission is allowed to
**delete only prebuilt workspaces**.
* A user with `workspace.delete` permission can **delete both normal and
prebuilt workspaces**.
⚠️ This implementation is scoped to **deletion operations only**. No
other operations are currently supported for the `prebuilt_workspace`
resource.
To delete a workspace, users must have the following permissions:
* `workspace.read`: to read the current workspace state
* `update`: to modify workspace metadata and related resources during
deletion (e.g., updating the `deleted` field in the database)
* `delete`: to perform the actual deletion of the workspace
## Changes
* Introduced `authorizeWorkspace()` helper to handle prebuilt workspace
authorization logic.
* Ensured both `prebuilt_workspace` and `workspace` permissions are
checked.
* Added comments to clarify the current behavior and limitations.
* Moved `SystemUserID` constant from the `prebuilds` package to the
`database` package `PrebuildsSystemUserID` to resolve an import cycle
(commit
https://github.com/coder/coder/pull/18333/commits/f24e4ab4b6f0a56726fd04be2d7302c9fdb52d53).
* Update middleware `ExtractOrganizationMember` to include system user
members.
Kyle Carberry