Parent repository customizations (#101)

[Arne Deutsch (ArneDeutsch)]

Problem

Custom instructions (.github/copilot-instructions.md, .github/instructions/*.instructions.md) and other customizations (prompt files, skills, custom agents) are discovered by the language server only inside the workspace folders it receives. Eclipse passes the project roots. In a typical multi-module repository, .github/ sits at the git repository root, while only the modules are imported as projects. Such customizations are therefore ignored, unless the repository root itself is imported as a project.

Solution

For every workspace folder that is located inside a git repository but is not its root, the folders up to and including the repository root are now passed to the language server as well. This mirrors VS Code's chat.useCustomizationsInParentRepositories. A .git file (worktrees, submodules) also marks a repository root, so the search stops at a submodule.

The extended folders are used for:

• chat requests (conversation/create, conversation/turn): always-on and applyTo instructions, skills offered to the agent, custom agents as sub-agents
• the slash command list (conversation/templates)
• the custom agent picker (conversation/modes)
• the customization file list used to auto-approve reads of these files
• the tool status of custom agents

A new preference, Also load custom instructions from the parent git repository of a project, on the Custom Instructions page controls the behavior. It is enabled by default: unlike VS Code, where the repository root is usually the opened folder, Eclipse projects are commonly nested inside the repository. Toggling it refreshes the slash commands and the customization file list; the agent picker reloads when it is opened. While it is enabled, the project table on the same page also lists parent repository folders containing a .github/copilot-instructions.md, and Edit opens that file.

Additional fix: prompt files in the slash command popup (separate commit)

The language server returns prompt files with the file URI as id and a separate name, and it resolves /command by that name. The popup showed and inserted the URI (e.g. /file:///c%3A/.../review.prompt.md -), so selecting a prompt file did not apply it. This also affected prompt files inside projects. The popup now uses the name, and the - separator is omitted for templates without a description.

How to test

Create a git repository with the customizations at its root, and import only the nested project into the workspace:

repro/                                        <- git root, not imported
├── .git/
├── .github/
│   ├── copilot-instructions.md               "Always end every response with [SRC-ROOT]"
│   ├── instructions/java.instructions.md     applyTo: "**/*.java"
│   ├── prompts/review.prompt.md
│   ├── skills/marker-skill/SKILL.md
│   └── agents/marker.agent.md
└── app/pom.xml                               <- only this project is imported

With the preference enabled (default), in a new chat each time:

1. Ask mode: the response ends with [SRC-ROOT].
2. With a .java file attached, the applyTo instruction is applied as well.
3. Agent mode: typing / lists /review and the skill; sending /review applies the prompt file.
4. Agent mode: the mode picker lists marker-agent; the agent can use the skill, and reading the root SKILL.md is auto-approved.
5. With projects inferred from chat-attached files, attaching a file of app/ also loads the root instructions.
6. Preferences → Custom Instructions: the project table lists repro (parent repository); Edit opens the root copilot-instructions.md.

Then uncheck the preference: none of the root customizations are used anymore, and the table row disappears immediately. The slash command list updates without restart, the agent picker on its next opening. A project whose root is the repository root behaves as before.

Open points

• The preference is enabled by default. We could consider to disable it by default. But as it is now it works out of the box. Otherwise users would have to discover that they could enable in preferences ... kind of awkwards.

[Arne Deutsch (ArneDeutsch)]

@microsoft-github-policy-service agree company="itemis AG"

[Copilot]

Copilot review overview

🟡 Changes recommended

The new checkbox may be invisible, parent agents are omitted from tool configuration, and asynchronous refreshes can restore stale parent files.

Review effort: Balanced
Findings: 1 · 2

Open (3)

• Prevent stale asynchronous refreshes from overwriting newer settings · New
• Resolve agent ownership using customization folders · New
• Add a layout so the preference checkbox is visible · New

What changed in this PR

Adds optional discovery of Copilot customizations from parent Git repositories and fixes prompt-file slash commands.

Changes:

• Extends workspace folders to parent repository roots.
• Adds an enabled-by-default preference and UI.
• Uses prompt names instead of URI identifiers for slash commands.

File	Description
messages.properties	Adds preference labels and parent-folder text.
Messages.java	Exposes new localized strings.
LanguageServerSettingManager.java	Refreshes customizations and extends tool-status scope.
CustomInstructionPreferencePage.java	Adds preference control and parent instruction rows.
CopilotPreferenceInitializer.java	Enables parent discovery by default.
ChatCompletionService.java	Loads parent templates and uses command names.
ChatView.java	Extends chat workspace folders.
ChatAssistProcessor.java	Corrects prompt completion display and insertion.
LanguageServerSettingManagerTests.java	Tests customization refresh events.
ChatCompletionServiceTest.java	Tests prompt-name command handling.
WorkspaceUtils.java	Implements repository-root discovery and folder expansion.
ConversationTemplate.java	Adds template names and command-name resolution.
Constants.java	Defines the preference key.
FileBasedCustomModeService.java	Discovers agents in parent repositories.
CustomizationFileService.java	Discovers parent customization files.
WorkspaceUtilsTests.java	Tests repository traversal and preference behavior.
ConversationTemplateTests.java	Tests slash-command name selection.

---

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[Copilot]

Copilot review overview

🟡 Changes recommended

Parent repository name collisions can configure the wrong custom agent, and the prompt popup regression lacks direct coverage.

Review effort: Balanced
Findings: 1 · 1

Open (2)

• Combo selection loses agent identity across duplicate repository names · New
• Resolve agent ownership using customization folders

Resolved since last review (2)

• Prevent stale asynchronous refreshes from overwriting newer settings
• Add a layout so the preference checkbox is visible

Previously missed (2)

In code that hasn't changed since last review

Test leaks preference manager listener across tests

com.microsoft.copilot.eclipse.ui.test/​src/​com/​microsoft/​copilot/​eclipse/​ui/​preferences/​LanguageServerSettingManagerTests.java:349

This test attaches a newly constructed manager to the process-wide preference store and never removes it. The listener therefore survives the test and reacts to later preference changes, including the reset in finally, which can post extra events and make subsequent tests order-dependent. Isolate the test with the mock preference store (invoke the captured listener/property change directly), or explicitly unregister the manager and dispose it during cleanup.

Missing regression test for prompt proposal display and insertion

com.microsoft.copilot.eclipse.ui/​src/​com/​microsoft/​copilot/​eclipse/​ui/​chat/​ChatAssistProcessor.java:134

The regression fix is only tested through ChatCompletionService.isCommand; no test exercises this proposal-building path. A regression could still display or insert the prompt URI, or restore the dangling separator for an empty description, while the added tests pass. Add a focused ChatAssistProcessorTest or SWTBot probe that selects a prompt-file proposal and verifies /review is displayed/inserted with no - suffix.

[Copilot]

Copilot review overview

🔵 Needs a closer look

Valid custom prompts named help or feedback are incorrectly filtered from slash commands.

Review effort: Balanced
Findings: 1

Open (1)

• Resolve agent ownership using customization folders

Resolved since last review (1)

• Combo selection loses agent identity across duplicate repository names

Previously missed (1)

In code that hasn't changed since last review

Exclude built-ins by ID, not prompt filename

com.microsoft.copilot.eclipse.ui/​src/​com/​microsoft/​copilot/​eclipse/​ui/​chat/​services/​ChatCompletionService.java:117

This now excludes user prompt files named help or feedback, because commandName() returns the prompt's name while its id is the file URI. EXCLUDED_COMMANDS is intended only to suppress the language server's IntelliJ-specific built-ins; preserving the original id check keeps those built-ins hidden without silently removing valid custom prompts.

[Arne Deutsch (ArneDeutsch)]

Regarding "Exclude built-ins by ID, not prompt filename": filtering by the command name is intended. help and feedback are built-in commands of the language server, and it resolves built-in commands before prompt files, removing the /help keyword from the message. A prompt file named help or feedback therefore can't be invoked through its slash command; listing it would run the built-in command instead, which Eclipse hides on purpose.

[Arne Deutsch (ArneDeutsch)]

This is for issue #101