gum-tool-output
Reference guide for Gum's Output tab system. Load this when working on the Output tab, IOutputManager, MainOutputViewModel, GuiCommands.PrintOutput, or adding output/error messages to the tool.
Best use case
gum-tool-output is best used when you need a repeatable AI agent workflow instead of a one-off prompt.
Reference guide for Gum's Output tab system. Load this when working on the Output tab, IOutputManager, MainOutputViewModel, GuiCommands.PrintOutput, or adding output/error messages to the tool.
Teams using gum-tool-output should expect a more consistent output, faster repeated execution, less prompt rewriting.
When to use this skill
- You want a reusable workflow that can be run more than once with consistent structure.
When not to use this skill
- You only need a quick one-off answer and do not need a reusable workflow.
- You cannot install or maintain the underlying files, dependencies, or repository context.
Installation
Claude Code / Cursor / Codex
Manual Installation
- Download SKILL.md from GitHub
- Place it in
.claude/skills/gum-tool-output/SKILL.mdinside your project - Restart your AI agent — it will auto-discover the skill
How gum-tool-output Compares
| Feature / Agent | gum-tool-output | Standard Approach |
|---|---|---|
| Platform Support | Not specified | Limited / Varies |
| Context Awareness | High | Baseline |
| Installation Complexity | Unknown | N/A |
Frequently Asked Questions
What does this skill do?
Reference guide for Gum's Output tab system. Load this when working on the Output tab, IOutputManager, MainOutputViewModel, GuiCommands.PrintOutput, or adding output/error messages to the tool.
Where can I find the source code?
You can find the source code on GitHub using the link provided at the top of the page.
SKILL.md Source
# Gum Tool Output System Reference ## Architecture **`IOutputManager`** (`Gum/Managers/MainOutputViewModel.cs`) — interface with two methods: - `AddOutput(string)` — appends a timestamped line - `AddError(string)` — appends a timestamped line prefixed with `"ERROR: "` (two spaces) **`MainOutputViewModel`** — implements `IOutputManager`. Stores all output as a single `OutputText` string (not a list). Registered as a singleton in DI, aliased as both `MainOutputViewModel` and `IOutputManager`. **`MainOutputPlugin`** — `InternalPlugin` that creates the Output tab at `TabLocation.RightBottom`. ## How to Write Output Inject `IOutputManager` and call `AddOutput` or `AddError` directly — this is the standard approach. Callers must already be on the UI thread. `IGuiCommands.PrintOutput` is a thin wrapper around `AddOutput` that marshals to the UI dispatcher — use this when calling from a background thread. There is **no `PrintError` equivalent** in `IGuiCommands`; callers needing `AddError` from a background thread must dispatch manually. ## Non-Obvious Behaviors - **Buffer cap**: `OutputText` is capped at 50,000 chars. When exceeded, it is trimmed to the last 25,000 chars — oldest output is silently discarded. - **No dispatcher in `IOutputManager`**: `AddOutput`/`AddError` write directly to the `OutputText` property with no thread marshaling. Calling from a background thread will throw. - **Auto-scroll**: The `TextBox` in the view uses `TextBoxAutoScroll.AutoScrollToEnd="True"` — new output scrolls into view automatically. ## Key Files | File | Purpose | |------|---------| | `Gum/Managers/MainOutputViewModel.cs` | `IOutputManager` interface + `MainOutputViewModel` implementation | | `Gum/Commands/GuiCommands.cs` | `PrintOutput` — dispatcher-safe wrapper | | `Gum/Commands/IGuiCommands.cs` | `PrintOutput` declaration | | `Gum/Plugins/InternalPlugins/Output/MainOutputPlugin.cs` | Registers the Output tab | | `Gum/Plugins/InternalPlugins/Output/MainOutputPluginView.xaml` | Output tab view (TextBox + clear button) | | `Gum/Services/Builder.cs` | DI registration of `MainOutputViewModel` as `IOutputManager` |
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