Bug: Thermos plugin subagents not available to Agent CLI Task tool

Summary

After installing the official Thermos plugin from cursor/plugins, invoking the thermos skill fails at step 3: Task rejects subagent_type: "thermo-nuclear-review-subagent" and thermo-nuclear-code-quality-review-subagent as invalid enum values. The CLI session never registers plugin-defined subagents.

Environment

• OS: Linux (dev server; no Cursor desktop IDE on this host)
• Agent CLI: agent --version → 2026.09.26-dd393fe
• cursor CLI: reports "No Cursor IDE installation found. Use 'cursor agent' or 'agent'"
• Plugin install: Thermos from cursor/plugins (local copy at ~/.cursor/plugins/local/thermos/ with .cursor-plugin/plugin.json, agents/, skills/); user also installed via /add-plugin thermos

Steps to reproduce

1. Install Thermos plugin (marketplace /add-plugin thermos or full tree under ~/.cursor/plugins/local/thermos/ from GitHub).
2. Run Agent CLI (agent) on Linux without Cursor desktop.
3. Attach / invoke thermos skill (orchestrator at plugin skills/thermos/SKILL.md).
4. In one message, call Task twice with run_in_background: true:
   • subagent_type: "thermo-nuclear-review-subagent"
   • subagent_type: "thermo-nuclear-code-quality-review-subagent"

Actual result

Both calls fail before any subagent runs:

subagent_type: Invalid enum value. Expected 'generalPurpose' | 'explore' | ... | 'code-reviewer' | ... | 'skill-reviewer',
received 'thermo-nuclear-review-subagent'

(same for thermo-nuclear-code-quality-review-subagent)

Plugin agent files exist, e.g. ~/.cursor/plugins/local/thermos/agents/thermo-nuclear-review-subagent.md.

Expected result

Per Thermos plugin README and thermos skill workflow, plugin subagents should be invokable via Task after install (as documented for editor/CLI subagent delegation). Step 3 should spawn both reviewers in parallel; step 5 synthesizes findings.

Impact

• Thermos cannot run as designed on CLI-only Linux dev servers.
• Agents that follow the skill correctly stop (no workaround without deviating from the skill).
• Docs/marketplace imply parallel thermo subagents; CLI Task schema does not expose them.

References

• Plugin: https://github.com/cursor/plugins/tree/main/thermos
• Thermos skill step 3: skills/thermos/SKILL.md
• Related forum pattern: custom/plugin subagents missing from Task enum (e.g. forum topic on not a valid subagent_type)
• Subagents docs: https://cursor.com/docs/subagents

Request

Register plugin-packaged subagents (at minimum Thermos thermo-nuclear-*-subagent) in the Agent CLI Task tool enum after plugin install, or document that Thermos requires Cursor desktop IDE and is unsupported on CLI-only hosts.