feat(irc): add interactive setup

feat(gateway): refine Platform._missing_ and platform-connected dispatch

Restricts plugin-name acceptance to bundled plugin scan + registry
(no arbitrary string -> enum-pollution), pulls per-platform connectivity
checks into a _PLATFORM_CONNECTED_CHECKERS lambda map with a clean
_is_platform_connected method, and adds tests covering the checker map,
plugin platform interface, and IRC setup wizard.

hermes_cli/config.py

@@ -1808,6 +1808,44 @@ OPTIONAL_ENV_VARS = {
         "advanced": True,
     },
 
+    # ── Bundled skills (opt-in: only needed if the user uses that skill) ──
+    # These use category="skill" (distinct from "tool") so the sandbox
+    # env blocklist in tools/environments/local.py does NOT rewrite them —
+    # skills legitimately need these passed through to curl via
+    # tools/env_passthrough.py when the user's skill calls out.
+    "NOTION_API_KEY": {
+        "description": "Notion integration token (used by the `notion` skill)",
+        "prompt": "Notion API key",
+        "url": "https://www.notion.so/my-integrations",
+        "password": True,
+        "category": "skill",
+        "advanced": True,
+    },
+    "LINEAR_API_KEY": {
+        "description": "Linear personal API key (used by the `linear` skill)",
+        "prompt": "Linear API key",
+        "url": "https://linear.app/settings/api",
+        "password": True,
+        "category": "skill",
+        "advanced": True,
+    },
+    "AIRTABLE_API_KEY": {
+        "description": "Airtable personal access token (used by the `airtable` skill)",
+        "prompt": "Airtable API key",
+        "url": "https://airtable.com/create/tokens",
+        "password": True,
+        "category": "skill",
+        "advanced": True,
+    },
+    "TENOR_API_KEY": {
+        "description": "Tenor API key for GIF search (used by the `gif-search` skill)",
+        "prompt": "Tenor API key",
+        "url": "https://developers.google.com/tenor/guides/quickstart",
+        "password": True,
+        "category": "skill",
+        "advanced": True,
+    },
+
     # ── Honcho ──
     "HONCHO_API_KEY": {
         "description": "Honcho API key for AI-native persistent memory",
@@ -2617,6 +2655,71 @@ def get_custom_provider_context_length(
     return None
 
 
+def get_custom_provider_context_length(
+    model: str,
+    base_url: str,
+    custom_providers: Optional[List[Dict[str, Any]]] = None,
+    config: Optional[Dict[str, Any]] = None,
+) -> Optional[int]:
+    """Look up a per-model ``context_length`` override from ``custom_providers``.
+
+    Matches any entry whose ``base_url`` equals ``base_url`` (trailing-slash
+    insensitive) and returns ``custom_providers[i].models.<model>.context_length``
+    if present and valid.  Returns ``None`` when no override applies.
+
+    This is the single source of truth for custom-provider context overrides,
+    used by:
+      * ``AIAgent.__init__`` (startup resolution)
+      * ``AIAgent.switch_model`` (mid-session ``/model`` switch)
+      * ``hermes_cli.model_switch.resolve_display_context_length`` (``/model`` confirmation display)
+      * ``gateway.run._format_session_info`` (``/info`` display)
+      * ``agent.model_metadata.get_model_context_length`` (when custom_providers is threaded through)
+
+    Before this helper existed, the lookup was duplicated in ``run_agent.py``'s
+    startup path only; every other path (notably ``/model`` switch) fell back
+    to the 128K default.  See #15779.
+    """
+    if not model or not base_url:
+        return None
+    if custom_providers is None:
+        try:
+            custom_providers = get_compatible_custom_providers(config)
+        except Exception:
+            if config is None:
+                return None
+            raw = config.get("custom_providers")
+            custom_providers = raw if isinstance(raw, list) else []
+    if not isinstance(custom_providers, list):
+        return None
+
+    target_url = (base_url or "").rstrip("/")
+    if not target_url:
+        return None
+
+    for entry in custom_providers:
+        if not isinstance(entry, dict):
+            continue
+        entry_url = (entry.get("base_url") or "").rstrip("/")
+        if not entry_url or entry_url != target_url:
+            continue
+        models = entry.get("models")
+        if not isinstance(models, dict):
+            continue
+        model_cfg = models.get(model)
+        if not isinstance(model_cfg, dict):
+            continue
+        raw_ctx = model_cfg.get("context_length")
+        if raw_ctx is None:
+            continue
+        try:
+            ctx = int(raw_ctx)
+        except (TypeError, ValueError):
+            continue
+        if ctx > 0:
+            return ctx
+    return None
+
+
 def check_config_version() -> Tuple[int, int]:
     """
     Check config version.