Anthropic task name responses can include valid JSON followed by a
closing fence or extra text, which made `json.Unmarshal` fail with
trailing-character errors and forced fallback naming.
This updates task name JSON extraction to accept the first JSON value
after optional fences and adds regression coverage for fenced and bare
JSON with trailing content.
- Adds `extractJSON()` to strip markdown code fences before JSON parsing and wire into the `json.Unmarshal` call in `generateFromAnthropic`.
- Accepts variadic `RequestOption` in `generateFromAnthropic` so tests can inject a mock Anthropic server via `WithBaseURL`.
- Adds table-driven cases covering bare JSON, fenced with/without language tag, surrounding whitespace, and multiline JSON.
- Adds end-to-end cases using `httptest.NewServer` to serve fake Anthropic SSE streams with bare and fenced responses.
## Problem
Tasks currently only expose a machine-friendly name field (e.g.
`task-python-debug-a1b2`), but this value is primarily an identifier
rather than a clean, descriptive label. We need a separate
display-friendly name for use in the UI.
This PR introduces a new `display_name` field and updates the task-name
generation flow. The Claude system prompt was updated to return valid
JSON with both `name` and `display_name`. The name generation logic
follows a fallback chain (Anthropic > prompt sanitization > random
fallback). To make task names more closely resemble their display names,
the legacy `task-` prefix has been removed. For context, PR
https://github.com/coder/coder/pull/20834 introduced a small Task icon
to the workspace list to help identify workspaces associated to tasks.
## Changes
- Database migration: Added `display_name` column to tasks table
- Updated system prompt to generate both task name and display name as
valid JSON
- Task name generation now follows a fallback chain: Anthropic > prompt
sanitization > random fallback
- Removed `task-` prefix from task names to allow more descriptive names
- Note: PR https://github.com/coder/coder/pull/20834 adds a Task icon to
workspaces in the workspace list to distinguish task-created workspaces
**Note:** UI changes will be addressed in a follow-up PR
Related to: https://github.com/coder/coder/issues/20801
Max Schwenk