mcp_viewer

Load states a configured MCP server can end up in.

ok means the server loaded successfully and has an authoritative tool list.

unauthenticated means the server requires OAuth login before tools can load.

error means the server failed to load after a connection or configuration failure.

disabled is set when the user has turned the server off via the TUI (/mcp -> F2). No connection is attempted and no tools are loaded, but the entry is still surfaced in the viewer so the user can re-enable it.

awaiting_reconnect is a transient UI-only state used after OAuth login has succeeded but before the LangGraph server has restarted and loaded the newly available MCP tools.

Sentinel returned by MCPViewerScreen.dismiss to request a reconnect.

The null-byte prefix makes the value un-collidable with any valid MCP server name returned by MCPServerInfo.name, so callers can branch on this exact string without weakening the existing server-name dispatch.

Textual Binding key for the in-viewer reconnect action.

Kept as a module constant so the footer hint and the help-text rendered in server headers stay in sync with the bound chord.

Display label for MCP_RECONNECT_KEY.

Shown in the footer hint chip and inline header prompts so the user sees the same chord text the binding will fire on.

Copy text to the system clipboard.

Get the glyph set for the current charset mode.

Check whether the terminal is in ASCII charset mode.

Convenience wrapper so widgets can branch on charset without importing both _detect_charset_mode and CharsetMode.

Neutralize control characters and deceptive Unicode in untrusted text.

Untrusted strings (MCP server errors, config-file contents, tool output) can carry ANSI escape sequences, other control characters, or invisible Unicode that corrupts the terminal, breaks out of a layout, or injects fake lines into logs and prompts. This first removes the invisible/bidi code points flagged by strip_dangerous_unicode, then replaces every remaining Unicode "Other" (control/format) character with a space.

Metadata for a configured MCP server and its tools.

Metadata for a single MCP tool.

Character glyphs for TUI display.

A selectable tool item in the MCP viewer.

Read-only modal for a failed MCP server's error details.

A selectable server-header row in the MCP viewer.

Cursor-selectable so users can navigate to every server — even those in unauthenticated or error states which have no tool rows by the MCPServerInfo invariant — and read the full status / error text on the line. Not expandable: Enter and Ctrl+E are no-ops here.

Modal viewer for active MCP servers and their tools.

Displays servers grouped by name with transport type and tool count. Navigate with arrow keys, Enter to expand/collapse tool descriptions, start in-app OAuth login for an unauthenticated server, or inspect a failed server. Ctrl+R requests a reconnect, F2 on a server header toggles its disabled state, and Escape closes the modal.

Dismisses with None when closed without action, the server name to drive an in-TUI OAuth login when the user activates an unauthenticated server header, or MCP_VIEWER_RECONNECT_REQUEST for a reconnect. The disable/enable toggle (F2) is handled in-place via the on_toggle_disable callback so the screen never tears down — see the constructor.

LangChain brand colors and semantic constants for the app.

Single source of truth for color values used in Python code (Rich markup, Content.styled, Content.from_markup). CSS-side styling should reference Textual CSS variables: built-in variables ($primary, $background, $text-muted, $error-muted, etc.) are set via register_theme() in DeepAgentsApp.__init__, while the few app-specific variables ($mode-bash, $mode-command, $mode-incognito, $skill, $skill-hover, $tool, $tool-hover) are backed by these constants via App.get_theme_variable_defaults().

Code that needs custom CSS variable values should call get_css_variable_defaults(dark=...). For the full semantic color palette, look up the ThemeColors instance via get_registry().

Users can define custom themes in ~/.deepagents/config.toml under [themes.<name>] sections. Each new theme section must include label (str); dark (bool) defaults to False if omitted (set to True for dark themes). Color fields are optional and fall back to the built-in dark/light palette based on the dark flag. Sections whose name matches a built-in theme override its colors without replacing it. See _load_user_themes() for details.