fix(connections): block incompatible servers and preserve saved environments

[rynfar]

Incompatible remote servers currently enter connection/retry flows without an explicit protocol check, and disconnecting saved environments can require removing them. This adds saved off-state, protocol preflight and disabled discovery entries, with neutral explanations and stable machine icons. Credentials, configuration and cached history remain saved while off.

Pylon keeps its connection layouts, editing controls, WSL lifecycle ownership and authentication parameters. Compatibility belongs to the saved target/profile; unrelated GitHub account-routing code is not imported. An explicit Check again action on web and reconnect on mobile clears an obsolete block and reruns preflight after a server upgrade. A still-incompatible server is blocked again before any RPC socket opens. Older descriptors without a version retain protocol 1 semantics; this does not guarantee compatibility between independently changed forks.

Sources through frozen head 6d1d549441be84f19696ab59ed7e2fbf305280d4:

• 2587c8060c103245b4f970b925977008f2592d1d (#11478), required saved off-state dependency; Theo Browne, co-author Claude Fable 5.1.
• 2c16c1d264173d86fc354e9a4c0c78cd42e514b7 (#11974), protocol preflight; Julius Marminge.
• 935c55b3778fdeae0e25b250ce2a9fa7e79c0327 (#11990), discovery gating; Julius Marminge.
• c1b2ed6504bbd57440d03c6a5af2736f33be7c65 (#12026), neutral unsupported presentation; Julius Marminge, co-author Claude Fable 5.1.
• 6ee03240bccd9287a8c2246e9547697aa5857998 (#12030), stable discovered icons; Julius Marminge, co-author Claude Fable 5.1.
  Original authored commits and source references are retained. Closes Upstream integration cycle: environment compatibility #594. Review cursor unchanged; no release/install.

Validation: 208 focused tests across compatibility/resolution, registry/retry, onboarding, persistence, contracts/server descriptor, web discovery, shared state and mobile projections. Scoped contracts/client-runtime/web/mobile/desktop/server typechecks and changed-file lint pass. Recovery regressions verify both an upgraded direct environment reconnecting and a still-incompatible environment remaining blocked without opening an RPC session.

Browser verification passed in isolated worktrees with a synthetic incompatible direct server: metadata is rechecked and zero RPC sockets open while unsupported. Before/after images and retry video. Native mobile rendered/live-relay verification is not claimed.

CI exposed a native dependency leaking into the existing mobile row unit test through ThemedSwitch; the fixture now mocks that component like its other native UI dependencies. All eight affected tests pass locally. All final-head CI checks pass at f0b455f19264eebfa83ce3f8162b0fb1d2cf63f5.

Implemented and verified with GPT-6 through the Codex harness.

[vercel]

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

Project	Deployment	Actions	Updated
pylon-marketing	Ready	Preview	Sep 17, 2026 3:24pm 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	13.9 KiB	−65 B (−0.5%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.2 KiB	7.2 KiB	−3 B (−0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.8 KiB	6.7 KiB	−62 B (−0.9%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	58.0 KiB	58.0 KiB	−88 B (−0.1%)	66.4 KiB	✅
Codex	Live turn messages	10	8	−2 (−20.0%)	21	✅
Claude	Total thread wire	14.0 KiB	14.0 KiB	+10 B (+0.1%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.2 KiB	7.2 KiB	+8 B (+0.1%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.8 KiB	6.8 KiB	+2 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: f3788ae · PR result: f0b455f · 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.

[rynfar]

Browser evidence from isolated Pylon worktrees, using a synthetic direct server advertising protocol 99. Before: repeated socket connection attempts. After: a neutral compatibility explanation, saved configuration retained, and an explicit Check again action. The retry capture rechecks metadata, stays blocked, and opens zero RPC sockets. Native mobile and live relay UI verification are not claimed.

Attachments in order: before, after, retry.

retry.mp4