feat(installer): add GitHub Copilot CLI target

CHANGELOG.md

@@ -14,6 +14,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - `codegraph init` now builds the initial index by default — you no longer need the `-i`/`--index` flag (it's still accepted, so existing commands and scripts keep working). (#483)
 - Go: Gin middleware chains now connect end-to-end in `codegraph_trace` and `codegraph_explore` — following a request reaches the middleware and route handlers registered via `.Use()` / `.GET()` instead of dead-ending where the framework dispatches the chain dynamically.
 - `codegraph_explore` now sizes its response to the *answer* instead of the file count: it shows the mechanism and the exact methods you asked about in full — even when they're buried deep in a large file — while collapsing the redundant interchangeable implementations of an interface (an HTTP interceptor chain, a query-compiler family) down to signatures. Fewer tokens for a more complete answer, so on the flows that used to occasionally cost more than plain grep/read it's now clearly cheaper — and the win holds across small, medium, and large codebases. Distinct, non-interchangeable code is shown in full as before. Disable with `CODEGRAPH_ADAPTIVE_EXPLORE=0`.
+- GitHub Copilot CLI: `codegraph install --target=copilot` now configures the Copilot CLI agent, writing MCP server entries to `~/.copilot/mcp-config.json` (global) or `.mcp.json` (local/workspace).
 
 ### Fixes
 

README.md

@@ -2,7 +2,7 @@
 
 # CodeGraph
 
-### Supercharge Claude Code, Cursor, Codex, OpenCode, Hermes Agent, Gemini, Antigravity, and Kiro with Semantic Code Intelligence
+### Supercharge Claude Code, Cursor, Codex, OpenCode, Hermes Agent, Gemini, Antigravity, Kiro, and Copilot CLI with Semantic Code Intelligence
 
 **~25% cheaper · ~62% fewer tool calls · 100% local**
 
@@ -24,6 +24,7 @@
 [![Gemini](https://img.shields.io/badge/Gemini-supported-blueviolet.svg)](#supported-agents)
 [![Antigravity](https://img.shields.io/badge/Antigravity-supported-blueviolet.svg)](#supported-agents)
 [![Kiro](https://img.shields.io/badge/Kiro-supported-blueviolet.svg)](#supported-agents)
+[![Copilot CLI](https://img.shields.io/badge/Copilot_CLI-supported-blueviolet.svg)](#supported-agents)
 
 </div>
 
@@ -46,7 +47,7 @@ npx @colbymchenry/codegraph        # zero-install, or:
 npm i -g @colbymchenry/codegraph
 ```
 
-<sub>CodeGraph bundles its own runtime — nothing to compile, no native build, works the same everywhere. The interactive installer auto-configures your agent(s) — Claude Code, Cursor, Codex CLI, opencode, Hermes Agent, Gemini CLI, Antigravity IDE, Kiro.</sub>
+<sub>CodeGraph bundles its own runtime — nothing to compile, no native build, works the same everywhere. The interactive installer auto-configures your agent(s) — Claude Code, Cursor, Codex CLI, opencode, Hermes Agent, Gemini CLI, Antigravity IDE, Kiro, Copilot CLI.</sub>
 
 ### Initialize Projects
 
@@ -571,6 +572,7 @@ is written):
 - **Gemini CLI**
 - **Antigravity IDE**
 - **Kiro**
+- **Copilot CLI**
 
 ## Supported Languages
 

__tests__/installer-targets.test.ts

@@ -494,6 +494,71 @@ describe('Installer targets — partial-state idempotency', () => {
     expect(paths.some((p) => p.endsWith('/.kiro/steering/codegraph.md'))).toBe(false);
   });
 
+  it('copilot: local install writes ./.mcp.json with "mcpServers" key', () => {
+    const copilot = getTarget('copilot')!;
+    const result = copilot.install('local', { autoAllow: true });
+    const mcpPath = path.join(tmpCwd, '.mcp.json');
+    expect(result.files.some((f) => f.path === mcpPath)).toBe(true);
+    expect(fs.existsSync(mcpPath)).toBe(true);
+
+    const cfg = JSON.parse(fs.readFileSync(mcpPath, 'utf-8'));
+    // Copilot CLI uses "mcpServers" (same as Claude/Cursor).
+    expect(cfg.mcpServers.codegraph).toBeDefined();
+    expect(cfg.mcpServers.codegraph.type).toBe('stdio');
+    expect(cfg.mcpServers.codegraph.command).toBeDefined();
+    expect(cfg.mcpServers.codegraph.args).toEqual(['serve', '--mcp']);
+  });
+
+  it('copilot: global install writes to ~/.copilot/mcp-config.json', () => {
+    const copilot = getTarget('copilot')!;
+    const result = copilot.install('global', { autoAllow: true });
+    const mcpPath = path.join(tmpHome, '.copilot', 'mcp-config.json');
+    expect(result.files.some((f) => f.path === mcpPath)).toBe(true);
+    expect(fs.existsSync(mcpPath)).toBe(true);
+
+    const cfg = JSON.parse(fs.readFileSync(mcpPath, 'utf-8'));
+    expect(cfg.mcpServers.codegraph).toBeDefined();
+    expect(cfg.mcpServers.codegraph.type).toBe('stdio');
+  });
+
+  it('copilot: install preserves a pre-existing sibling MCP server in .mcp.json', () => {
+    const copilot = getTarget('copilot')!;
+    const mcpPath = path.join(tmpCwd, '.mcp.json');
+    fs.mkdirSync(path.dirname(mcpPath), { recursive: true });
+    fs.writeFileSync(mcpPath, JSON.stringify({
+      mcpServers: { other: { type: 'stdio', command: 'uvx', args: ['other-server'] } },
+    }, null, 2) + '\n');
+
+    copilot.install('local', { autoAllow: true });
+
+    const after = JSON.parse(fs.readFileSync(mcpPath, 'utf-8'));
+    expect(after.mcpServers.other).toBeDefined();
+    expect(after.mcpServers.codegraph).toBeDefined();
+  });
+
+  it('copilot: uninstall strips codegraph but leaves sibling MCP servers intact', () => {
+    const copilot = getTarget('copilot')!;
+    const mcpPath = path.join(tmpCwd, '.mcp.json');
+    fs.mkdirSync(path.dirname(mcpPath), { recursive: true });
+    fs.writeFileSync(mcpPath, JSON.stringify({
+      mcpServers: { other: { type: 'stdio', command: 'uvx', args: ['other-server'] } },
+    }, null, 2) + '\n');
+
+    copilot.install('local', { autoAllow: true });
+    copilot.uninstall('local');
+
+    const after = JSON.parse(fs.readFileSync(mcpPath, 'utf-8'));
+    expect(after.mcpServers.other).toBeDefined();
+    expect(after.mcpServers.codegraph).toBeUndefined();
+  });
+
+  it('copilot: printConfig returns mcpServers format', () => {
+    const copilot = getTarget('copilot')!;
+    const output = copilot.printConfig('local');
+    expect(output).toContain('"mcpServers"');
+    expect(output).toContain('codegraph');
+  });
+
   it('antigravity: install writes to LEGACY ~/.gemini/antigravity/mcp_config.json when no migration marker', () => {
     const antigravity = getTarget('antigravity')!;
     antigravity.install('global', { autoAllow: true });
@@ -1098,6 +1163,7 @@ describe('Installer targets — registry', () => {
     expect(getTarget('gemini')?.id).toBe('gemini');
     expect(getTarget('antigravity')?.id).toBe('antigravity');
     expect(getTarget('kiro')?.id).toBe('kiro');
+    expect(getTarget('copilot')?.id).toBe('copilot');
     expect(getTarget('not-a-real-target')).toBeUndefined();
   });
 

src/bin/codegraph.ts

@@ -1607,7 +1607,7 @@ program
  */
 program
   .command('install')
-  .description('Install codegraph MCP server into one or more agents (Claude Code, Cursor, Codex CLI, opencode, Hermes Agent)')
+  .description('Install codegraph MCP server into one or more agents (Claude Code, Cursor, Codex CLI, opencode, Hermes Agent, Copilot CLI)')
   .option('-t, --target <ids>', 'Target agent(s): comma-separated ids, or "auto"|"all"|"none". Default: prompt')
   .option('-l, --location <where>', 'Install location: "global" or "local". Default: prompt')
   .option('-y, --yes', 'Non-interactive: defaults to --location=global --target=auto, auto-allow on')
@@ -1674,7 +1674,7 @@ program
  */
 program
   .command('uninstall')
-  .description('Remove codegraph from your agents (Claude Code, Cursor, Codex CLI, opencode, Hermes Agent)')
+  .description('Remove codegraph from your agents (Claude Code, Cursor, Codex CLI, opencode, Hermes Agent, Copilot CLI)')
   .option('-t, --target <ids>', 'Target agent(s): comma-separated ids, or "all". Default: all')
   .option('-l, --location <where>', 'Uninstall location: "global" or "local". Default: prompt')
   .option('-y, --yes', 'Non-interactive: defaults to --location=global --target=all')

src/installer/index.ts

@@ -257,35 +257,79 @@ export interface UninstallReport {
  *
  * Each target's `uninstall()` is already safe to call when nothing was
  * installed (it returns `not-found` actions), so this is safe to run
- * across every target unconditionally.
+ * across every target unconditionally.  We still gate on `detect()`
+ * for targets that share a config file (e.g. `.mcp.json` is used by
+ * both Claude Code and Copilot CLI for local installs) — without the
+ * gate, one agent's uninstall would strip the other agent's entry
+ * from the shared file.
+ *
+ * When a shared config file has its codegraph entry removed, other
+ * targets that also write to that same file are marked "removed" as
+ * well — because the entry they rely on no longer exists.  A note
+ * explains the cascade so the user understands what happened.
  */
 export function uninstallTargets(
   targets: readonly AgentTarget[],
   location: Location,
 ): UninstallReport[] {
-  return targets.map((target) => {
+  // Track config paths that had their codegraph entry removed.
+  // When multiple targets share a file (e.g. .mcp.json), removing
+  // the entry for one target removes it for all of them.
+  const removedConfigPaths = new Set<string>();
+  const reports: UninstallReport[] = [];
+
+  for (const target of targets) {
     if (!target.supportsLocation(location)) {
       const only: Location = location === 'local' ? 'global' : 'local';
-      return {
+      reports.push({
         id: target.id,
         displayName: target.displayName,
         status: 'unsupported' as const,
         removedPaths: [],
         notes: [`no ${location} config — this agent is ${only}-only`],
-      };
+      });
+      continue;
+    }
+    if (!target.detect(location).installed) {
+      reports.push({
+        id: target.id,
+        displayName: target.displayName,
+        status: 'not-configured' as const,
+        removedPaths: [],
+        notes: [],
+      });
+      continue;
     }
+
+    // Check if a prior target already removed the entry from this
+    // target's config file (shared-file cascade).
+    const cfgPath = target.detect(location).configPath;
+    if (cfgPath && removedConfigPaths.has(cfgPath)) {
+      reports.push({
+        id: target.id,
+        displayName: target.displayName,
+        status: 'removed' as const,
+        removedPaths: [cfgPath],
+        notes: [`shared config file (${cfgPath}) — entry was already removed by a previous uninstall`],
+      });
+      continue;
+    }
+
     const result = target.uninstall(location);
     const removedPaths = result.files
       .filter((f) => f.action === 'removed')
       .map((f) => f.path);
-    return {
+    for (const p of removedPaths) removedConfigPaths.add(p);
+    reports.push({
       id: target.id,
       displayName: target.displayName,
       status: removedPaths.length > 0 ? ('removed' as const) : ('not-configured' as const),
       removedPaths,
       notes: result.notes ?? [],
-    };
-  });
+    });
+  }
+
+  return reports;
 }
 
 /**
@@ -317,7 +361,7 @@ export async function runUninstaller(opts: RunUninstallerOptions): Promise<void>
     const sel = await clack.select({
       message: 'Remove CodeGraph from all your projects, or just this one?',
       options: [
-        { value: 'global' as const, label: 'All projects (global)', hint: '~/.claude, ~/.cursor, ~/.codex, ~/.config/opencode, ~/.hermes, ~/.gemini, ~/.kiro' },
+        { value: 'global' as const, label: 'All projects (global)', hint: '~/.claude, ~/.cursor, ~/.codex, ~/.config/opencode, ~/.hermes, ~/.gemini, ~/.kiro, ~/.copilot' },
         { value: 'local'  as const, label: 'Just this project (local)', hint: './.claude, ./.cursor, ./opencode.jsonc, ./.gemini, ./.kiro' },
       ],
       initialValue: 'global' as const,
@@ -353,13 +397,40 @@ export async function runUninstaller(opts: RunUninstallerOptions): Promise<void>
       for (const p of r.removedPaths) {
         clack.log.success(`${r.displayName}: removed ${tildify(p)}`);
       }
+      if (r.notes.length > 0) {
+        for (const n of r.notes) {
+          clack.log.warn(`${r.displayName}: ${n}`);
+        }
+      }
     } else if (r.status === 'not-configured') {
       clack.log.info(`${r.displayName}: not configured — nothing to remove`);
     } else {
       clack.log.info(`${r.displayName}: skipped — ${r.notes[0] ?? 'unsupported location'}`);
     }
   }
 
+  // Step 3b: warn about shared-config cascade.  When multiple targets
+  // write to the same file (e.g. .mcp.json is shared by Claude Code,
+  // Cursor, and Copilot CLI for local installs), removing the
+  // codegraph entry for one target also removes it for the others.
+  const removedPaths = new Set(removed.flatMap((r) => r.removedPaths));
+  if (removedPaths.size > 0) {
+    const affected = ALL_TARGETS.filter((t) => {
+      if (reports.some((r) => r.id === t.id && r.status === 'removed')) return false;
+      if (!t.supportsLocation(location)) return false;
+      const det = t.detect(location);
+      return det.installed && det.configPath && removedPaths.has(det.configPath);
+    });
+    if (affected.length > 0) {
+      const names = affected.map((t) => t.displayName).join(', ');
+      const files = [...removedPaths].map((p) => tildify(p)).join(', ');
+      clack.log.warn(
+        `Shared config: ${files} is also used by ${names}. ` +
+        `The codegraph entry was removed from that file — those agents will need re-installing.`,
+      );
+    }
+  }
+
   // Step 4: for local uninstall, the index dir is separate — point at
   // `uninit` so the user knows it's still there (and how to remove it).
   if (location === 'local' && fs.existsSync(path.join(process.cwd(), '.codegraph'))) {

src/installer/targets/claude.ts

@@ -86,9 +86,15 @@ class ClaudeCodeTarget implements AgentTarget {
     // For "installed" we infer from the existence of either the dir
     // (global) or the project marker file (local). Cheap and avoids
     // shelling out to `claude --version`.
+    // For local: .mcp.json is shared infrastructure (Copilot CLI
+    // also writes to it), so we CANNOT use it as a Claude-specific
+    // detection signal.  Only .claude/ is Claude's own marker.
+    // Copilot has no equivalent local dir, so it keeps .mcp.json
+    // as its detection signal.  The shared-config cascade in
+    // uninstallTargets handles the conflict when both are installed.
     const installed = loc === 'global'
       ? fs.existsSync(configDir(loc)) || fs.existsSync(mcpPath)
-      : fs.existsSync(mcpPath) || fs.existsSync(configDir(loc));
+      : fs.existsSync(configDir(loc));
     return { installed, alreadyConfigured, configPath: mcpPath };
   }