fix(devices): skip local SSH hosts and check selected environments

[rynfar]

SSH device hosts that resolve to the environment server's own machine currently try to connect back over SSH, while adding a host checks only the primary environment even when several environments are selected. A local target now resolves to the existing local device host; forwarded ports, proxies, remote addresses, and unresolved targets remain SSH hosts. Adding or editing a host checks every selected environment independently, with results tied to the target and environment set. Saving still updates the environment shown in Pylon's Devices section.

This adapts upstream 1ced38a6647b7f466b535b4b413ca4a74303da8e and 8984f8103d0836c0b340fe70cd053428d622a8c3 while preserving Pylon's provider settings mutation fence, selected-environment ownership, host Retry action, and tool status. The web source is a Pylon adaptation rather than a wholesale component copy.

Validation: 7 focused server/web tests, t3 and web typechecks, scoped lint and formatting, and clean diff checks passed. Server tests cover local, remote, forwarded, proxied, and unresolved destinations; web tests cover independent environment outcomes, input normalization, and stale-result fencing. Browser before/after images were not captured because browser use requires separate authorization under AGENTS.md. No isolated live SSH test host was available, so remote end-to-end verification was not performed.

Implemented by GPT-6 Sol in the Codex/Pylon harness.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

1 Skipped Deployment

Project	Deployment	Actions	Updated
pylon-marketing	Ignored	Preview	Sep 24, 2026 9:01am UTC

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	14.0 KiB	14.0 KiB	+6 B (+0.0%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.2 KiB	7.2 KiB	−1 B (−0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.8 KiB	6.8 KiB	+7 B (+0.1%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	58.0 KiB	58.0 KiB	0 B (0.0%)	66.4 KiB	✅
Codex	Live turn messages	10	10	0 (0.0%)	21	✅
Claude	Total thread wire	14.0 KiB	14.0 KiB	−3 B (−0.0%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.2 KiB	7.2 KiB	−3 B (−0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.7 KiB	6.7 KiB	0 B (0.0%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	58.9 KiB	58.9 KiB	−44 B (−0.1%)	66.4 KiB	✅
Claude	Live turn messages	10	9	−1 (−10.0%)	21	✅

Baseline: 7ed3f71 · PR result: f134b4e · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 115.6 KiB
• Claude decoded thread snapshot: 116.3 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.