Transport failure: no webhook hit / listener closed.
Authorization failure: sender not allowed or pairing pending.
Adapter filtering: message acknowledged but intentionally skipped, e.g. group mention gating, tapback filtering, or self-message loop guard.

For user-visible claims, verify with real command output: hermes status, listener checks, webhook health, and gateway logs.
When changing Hermes gateway config or adapter code, restart the gateway and verify the adapter reconnects.
For gateway slash-command failures, inspect session-origin scope separately from transport health:

Compare source, user_id, chat_id, thread_id, and origin_json in the live session database.
Trace both the listing path and the action path; a session browser is still broken if it lists a target that /resume rejects.
In forum/threaded platforms, distinguish same-parent-chat ownership from exact-thread isolation rather than weakening origin checks globally.

Telegram forum session browsing

A fresh Telegram forum topic can have no prior exact-thread sessions even when the same owner has many titled sessions in sibling topics of the same parent chat.
Do not diagnose this from session history alone. Correlate gateway send logs, live DB origin columns, and the gateway routing origin.
Cross-topic browsing must be Telegram-specific, same-parent-chat, and same-owner; thread_sessions_per_user=false permits sharing within one thread, not across sibling threads.
Keep /sessions visibility and /resume authorization aligned, including persisted-only rows.
See references/telegram-forum-session-scope.md for the reproduction, authorization contract, TDD matrix, and safe activation procedure.

BlueBubbles / iMessage notes

BlueBubbles may mark messages from the Mac's own Apple ID/iMessage identity as isFromMe=true.
A blanket isFromMe skip prevents reply loops but also prevents the owner from texting Hermes from that same iMessage identity.
The safer loop guard is outbound-ID based: remember Hermes-sent tempGuid and returned guid/messageGuid, then ignore only inbound webhook echoes whose IDs match that cache.
On macOS, do not assume localhost reaches an IPv4-only Hermes webhook. BlueBubbles/Electron/Node may resolve localhost to IPv6 ::1, causing connect ECONNREFUSED ::1:<port> while curl http://127.0.0.1:<port>/health still works. Register local BlueBubbles webhooks as http://127.0.0.1:<port>/... unless Hermes is listening on IPv6 too.
See references/bluebubbles-self-imessage-loop-guard.md for the concrete fix pattern, localhost/IPv6 pitfall, stale-webhook cleanup, and verification loop.
See references/memory-context-injection-probes.md for probe handling when recalled-memory wrappers, formatting-failure echoes, or outbound test messages appear in a live platform chat.

Do not confuse “gateway open” with “message authorized.” A listener can be healthy while the sender is ignored by allowlist/pairing logic.
If Telegram is fast for text but a photo/image turn appears to run forever, inspect agent.log for repeated API calls ending in TypeError: expected string or bytes-like object, got 'list' from _interim_assistant_visible_text → strip_think_blocks. This was a multimodal block-list regression introduced by Codex interim-commentary handling; a current upstream release fixes the loop. Stop the affected turn, update Hermes through the normal update-safe procedure, reapply local patches, restart the gateway, and verify with a real photo+caption message. Transport latency and gateway health can look completely normal while this retry loop burns up to the agent iteration cap.
Do not persist negative claims like “BlueBubbles ignores self messages” as a permanent tool limitation. The durable lesson is the loop-guard design.
Do not edit protected bundled skills; place Hermes-gateway-specific operational learnings here when bundled skills cannot be patched.