Interop Matrix

Interop Matrix

VS Code Copilot has grown to read most of Claude Code's configuration natively. FeatherSpec leans on that overlap: rules, the constitution, the workflow bodies and the Memory Bank are single files that both tools read. Only genuinely tool-specific things stay separate.

What GitHub Copilot in VS Code reads from .claude/

Artifact	Claude Code	VS Code Copilot	Caveats
AGENTS.md (constitution)	via @AGENTS.md import in CLAUDE.md	native, chat.useAgentsMdFile (default on)	the single source of truth for both
CLAUDE.md	native	native, chat.useClaudeMdFile (default on) — off here on purpose	we point Copilot straight at AGENTS.md, so the one-line import file is redundant for it
.claude/rules/*.md (paths:)	native, loads when a matching file is read	native — reads paths: instead of applyTo:; defaults to ** when omitted	the two official pages disagree: custom instructions lists .claude/rules as a default workspace location, while the settings reference default value omits it ({ ".github/instructions": true, "~/.claude/rules": false }). .vscode/settings.json enables it explicitly, so the repo works either way
.claude/commands/<name>.md (workflow body)	native, /<name> from the file name; disable-model-invocation: true keeps the description out of context	not read directly — reached through the .github/prompts loader below	the body is written once and both tools execute the same text
.github/prompts/<name>.prompt.md (loader)	— (ignored)	native, /<name>; .github/prompts is the default location and the .prompt.md extension is required	a prompt file is user-invoked only, never offered to the model; each loader is a link to the body and holds no rules
Web research from inside a workflow	native WebSearch (US-only) and WebFetch	built-in #fetch for a page, plus the web tool in agent mode	/sdd-plan asks for "your web search or fetch capability" rather than naming a tool, and requires the model to say so when none is available instead of guessing
.github/agents/*.agent.md	— (kept Copilot-only, see below)	native — .github/agents is a default location (chat.agentFilesLocations)	a Copilot custom agent is a selectable persona
hooks in .claude/settings.json	native (with matchers)	reads .claude/settings.json, .claude/settings.local.json and ~/.claude/settings.json; parses Claude's format	VS Code ignores matcher values — hooks run on all tool invocations, so a shared hook must filter on tool_name in the script

Not shared — stays separate

Artifact	Claude Code	VS Code Copilot
The slash-command entry point	.claude/commands/*.md	.github/prompts/*.prompt.md — different folder and extension, so one file cannot serve both; FeatherSpec ships a one-line Copilot loader per command and keeps the body in .claude/commands/
Agent skills (.claude/skills/<name>/SKILL.md)	native, /<name>	native, .claude/skills is a default location
!`shell` injection, $ARGUMENTS, $0/$1	supported	not supported — the documented mechanism is ${input:…} — so the shared bodies use neither
Everything in .claude/settings.json except hooks (autoMemoryEnabled, permissions, …)	native	no documented support (treat as ignored)
MCP servers	.mcp.json, root key mcpServers	.vscode/mcp.json, root key servers
Auto memory	~/.claude/projects/<project>/memory/	no equivalent
Output styles, plugins/marketplaces	Claude-specific	Copilot-specific

The .vscode/settings.json that makes it explicit

Every location above is already a VS Code default, so a fresh clone works untouched. The shipped settings file restates them so the setup survives a changed default or a workspace that overrode one:

{
  "chat.useAgentsMdFile": true,
  "chat.useClaudeMdFile": false,
  "chat.instructionsFilesLocations": { ".claude/rules": true },
  "chat.promptFilesLocations": { ".github/prompts": true },
  "chat.agentFilesLocations": { ".github/agents": true, ".claude/agents": true }
}

The SpecDrivenAgent asymmetry

.github/agents/SpecDrivenAgent.agent.md is kept Copilot-only on purpose. VS Code would also read a .claude/agents/ file, but the semantics differ:

• In Copilot, a custom agent is a persona you pick from a dropdown — it shapes the same conversation you are already in.
• In Claude Code, a .claude/agents/ file is an isolated subagent with its own context window that does not share your conversation.

Same file location, different meaning. Claude Code has no persona picker, and that is fine: the persona there is AGENTS.md (always loaded via @AGENTS.md) plus /sdd-overview for the greeting and the map.

Sources

VS Code: custom instructions · agent skills · custom agents · hooks · agent tools · settings reference. Claude Code: skills · memory/rules.