feat(agent): add Gemini CLI as an install target

src/commands/agent.test.ts

@@ -779,8 +779,8 @@ describe('runList', () => {
 
     const json = JSON.parse(capture.stdout.join('\n')) as ListResult[];
     expect(Array.isArray(json)).toBe(true);
-    // 8 targets × 2 default skills = 16 rows
-    expect(json).toHaveLength(16);
+    // 9 targets x 2 default skills = 18 rows
+    expect(json).toHaveLength(18);
     const targets = json.map(r => r.target);
     expect(targets).toContain('claude');
     expect(targets).toContain('cursor');

src/commands/agent.ts

@@ -22,6 +22,7 @@ import {
   renderForTarget,
   renderOwnFileWithMarker,
   MANAGED_SECTION_BEGIN,
+  MANAGED_SECTION_BEGIN_LEGACY,
   MANAGED_SECTION_END,
 } from '../lib/agent-targets.js';
 
@@ -206,7 +207,8 @@ function classifySection(existing: string, section: string): SectionState {
 
   for (let i = 0; i < lines.length; i++) {
     const stripped = (lines[i] ?? '').trimEnd();
-    if (stripped === MANAGED_SECTION_BEGIN) beginLines.push(i);
+    if (stripped === MANAGED_SECTION_BEGIN || stripped === MANAGED_SECTION_BEGIN_LEGACY)
+      beginLines.push(i);
     else if (stripped === MANAGED_SECTION_END) endLines.push(i);
   }
 
@@ -1062,7 +1064,7 @@ function collect(v: string, prev: string[]): string[] {
 
 export function createAgentCommand(deps: AgentDeps = {}): Command {
   const agent = new Command('agent').description(
-    'Install TestSprite guidance into coding-agent config (Claude Code, Cursor, Cline, Antigravity, Kiro, Windsurf, Copilot, Codex)',
+    'Install TestSprite guidance into coding-agent config (Claude Code, Cursor, Cline, Antigravity, Kiro, Windsurf, Copilot, Gemini, Codex)',
   );
 
   agent
@@ -1072,7 +1074,7 @@ export function createAgentCommand(deps: AgentDeps = {}): Command {
     )
     .option(
       '--target <t>',
-      'Agent target(s): claude, cursor, cline, antigravity, kiro, windsurf, copilot, codex (comma-separated or repeated)',
+      'Agent target(s): claude, cursor, cline, antigravity, kiro, windsurf, copilot, gemini, codex (comma-separated or repeated)',
       collect,
       [],
     )
@@ -1086,7 +1088,7 @@ export function createAgentCommand(deps: AgentDeps = {}): Command {
     .option(
       '--force',
       'For own-file targets: overwrite existing file (a .bak backup is kept). ' +
-        'For codex (managed-section): replaces the section unconditionally; user content outside the section is never destroyed.',
+        'For managed-section targets (codex, gemini): replaces the section unconditionally; user content outside the section is never destroyed.',
     )
     .addHelpText('after', GLOBAL_OPTS_HINT)
     .action(

src/lib/agent-targets.test.ts

@@ -5,6 +5,7 @@ import { VERSION } from '../version.js';
 import {
   DEFAULT_SKILLS,
   MANAGED_SECTION_BEGIN,
+  MANAGED_SECTION_BEGIN_LEGACY,
   MANAGED_SECTION_END,
   ONBOARD_CODEX_LINE,
   SKILL_DESCRIPTION,
@@ -82,7 +83,7 @@ testsprite test artifact get <run-id> --out ./out/
 // ---------------------------------------------------------------------------
 
 describe('TARGETS', () => {
-  it('has all eight required keys', () => {
+  it('has all nine required keys', () => {
     const keys = Object.keys(TARGETS).sort();
     expect(keys).toEqual([
       'antigravity',
@@ -91,6 +92,7 @@ describe('TARGETS', () => {
       'codex',
       'copilot',
       'cursor',
+      'gemini',
       'kiro',
       'windsurf',
     ]);
@@ -100,11 +102,12 @@ describe('TARGETS', () => {
     expect(TARGETS.claude.status).toBe('ga');
   });
 
-  it('cursor, cline, windsurf, copilot, antigravity, kiro, and codex are experimental', () => {
+  it('cursor, cline, windsurf, copilot, gemini, antigravity, kiro, and codex are experimental', () => {
     expect(TARGETS.cursor.status).toBe('experimental');
     expect(TARGETS.cline.status).toBe('experimental');
     expect(TARGETS.windsurf.status).toBe('experimental');
     expect(TARGETS.copilot.status).toBe('experimental');
+    expect(TARGETS.gemini.status).toBe('experimental');
     expect(TARGETS.antigravity.status).toBe('experimental');
     expect(TARGETS.kiro.status).toBe('experimental');
     expect(TARGETS.codex.status).toBe('experimental');
@@ -127,8 +130,9 @@ describe('TARGETS', () => {
     expect(TARGETS.copilot.mode).toBe('own-file');
   });
 
-  it('codex target has mode managed-section', () => {
+  it('codex and gemini targets have mode managed-section', () => {
     expect(TARGETS.codex.mode).toBe('managed-section');
+    expect(TARGETS.gemini.mode).toBe('managed-section');
   });
 
   it('codex target path is AGENTS.md', () => {
@@ -386,6 +390,47 @@ describe('renderForTarget("copilot")', () => {
   });
 });
 
+describe('renderForTarget("gemini")', () => {
+  const result = renderForTarget('gemini', 'testsprite-verify', STUB_BODY);
+
+  it('returns GEMINI.md as the landing path', () => {
+    expect(result.path).toBe('GEMINI.md');
+  });
+
+  it('does not emit YAML frontmatter (plain Markdown, no --- fence)', () => {
+    expect(result.content.startsWith('---\n')).toBe(false);
+    expect(result.content).not.toContain('name:');
+    expect(result.content).not.toContain('applyTo:');
+    expect(result.content).not.toContain('trigger:');
+  });
+
+  it('contains the stub body verbatim', () => {
+    expect(result.content).toContain(STUB_BODY);
+  });
+
+  it('renders the verify body content (managed-section, compact codex body)', () => {
+    // Uses real bodies: gemini uses the codex contribution body (compact).
+    // renderForTarget for managed-section intentionally returns the unwrapped
+    // body without sentinels — sentinel wrapping is an install-time concern
+    // performed by buildSection in agent.ts, not by renderForTarget.
+    const gemini = renderForTarget('gemini', 'testsprite-verify');
+    expect(gemini.content).toContain('testsprite test run');
+  });
+
+  it('gemini managed-section body is wrapped in sentinels when installed (sentinel contract)', () => {
+    // Verify the sentinel contract at the layer where it is enforced:
+    // the install command wraps the body from renderForTarget in MANAGED_SECTION_BEGIN/END.
+    // We test this indirectly via the exported constants to confirm the sentinel
+    // strings are defined, well-formed HTML comments, and target-neutral.
+    expect(MANAGED_SECTION_BEGIN).toContain('BEGIN TESTSPRITE AGENT SECTION');
+    expect(MANAGED_SECTION_END).toContain('END TESTSPRITE AGENT SECTION');
+    // Sentinel must be target-neutral — must NOT say 'codex'
+    expect(MANAGED_SECTION_BEGIN).not.toContain('codex');
+    // Legacy sentinel exists for backward compat with existing AGENTS.md files
+    expect(MANAGED_SECTION_BEGIN_LEGACY).toContain('codex');
+  });
+});
+
 // ---------------------------------------------------------------------------
 // Content integrity — load-bearing command strings must survive any body trim
 // ---------------------------------------------------------------------------

src/lib/agent-targets.ts

@@ -10,7 +10,8 @@ export type AgentTarget =
   | 'codex'
   | 'kiro'
   | 'windsurf'
-  | 'copilot';
+  | 'copilot'
+  | 'gemini';
 
 export interface TargetSpec {
   status: 'ga' | 'experimental';
@@ -189,6 +190,8 @@ export function pathFor(target: AgentTarget, skill: string): string {
       return `.windsurf/rules/${skill}.md`;
     case 'copilot':
       return `.github/instructions/${skill}.instructions.md`;
+    case 'gemini':
+      return 'GEMINI.md';
     case 'codex':
       return 'AGENTS.md';
   }
@@ -243,11 +246,34 @@ export const TARGETS: Record<AgentTarget, TargetSpec> = {
     // GitHub Copilot path-specific instructions: frontmatter carries `applyTo`.
     // `applyTo: '**'` means the file is ALWAYS injected into Copilot requests
     // (there is no on-demand "model decides" mode like Cursor/Windsurf), so
-    // render the compact body to keep the always-on context cost small — the
+    // render the compact body to keep the always-on context cost small -- the
     // same reasoning that drives windsurf's compact render.
     compactBody: true,
     wrap: wrapCopilot,
   },
+  /**
+   * gemini target -- managed-section mode (GEMINI.md).
+   *
+   * Gemini CLI reads project-level instructions from a `GEMINI.md` file in
+   * the repo root. The file is plain Markdown, loaded at the start of every
+   * session (always-on). Because all installed skills share this single file
+   * we use managed-section mode -- the same approach as codex/AGENTS.md --
+   * writing only a sentinel-delimited section so any existing user content
+   * in GEMINI.md is never clobbered.
+   *
+   * The compact body is used (same reasoning as windsurf/copilot): GEMINI.md
+   * is always-injected, so keeping it small reduces context cost.
+   *
+   * --force replaces the managed section unconditionally but never touches
+   * content outside the sentinels.
+   */
+  gemini: {
+    status: 'experimental',
+    path: pathFor('gemini', SKILL_NAME),
+    mode: 'managed-section',
+    // GEMINI.md is plain Markdown; wrap is a no-op (no frontmatter).
+    wrap: (_name, _description, body) => body,
+  },
   /**
    * codex target — managed-section mode.
    *
@@ -274,11 +300,20 @@ export const TARGETS: Record<AgentTarget, TargetSpec> = {
   },
 };
 
-/** Sentinel pair that bounds our managed section in AGENTS.md. */
+/** Sentinel pair that bounds our managed section in AGENTS.md / GEMINI.md. */
 export const MANAGED_SECTION_BEGIN =
-  '<!-- BEGIN TESTSPRITE AGENT SECTION (testsprite agent install codex) -->';
+  '<!-- BEGIN TESTSPRITE AGENT SECTION (testsprite agent install) -->';
 export const MANAGED_SECTION_END = '<!-- END TESTSPRITE AGENT SECTION -->';
 
+/**
+ * Legacy sentinel written by versions prior to this change.
+ * Kept for backward-compatibility: existing AGENTS.md files that contain
+ * the old Codex-labelled marker are still recognised as a valid managed
+ * section during classify / replace operations.
+ */
+export const MANAGED_SECTION_BEGIN_LEGACY =
+  '<!-- BEGIN TESTSPRITE AGENT SECTION (testsprite agent install codex) -->';
+
 // ---------------------------------------------------------------------------
 // Install marker (stale-skill detection, issue #123)
 // ---------------------------------------------------------------------------

test/__snapshots__/help.snapshot.test.ts.snap

@@ -4,7 +4,7 @@ exports[`--help snapshots > agent 1`] = `
 "Usage: testsprite agent [options] [command]
 
 Install TestSprite guidance into coding-agent config (Claude Code, Cursor,
-Cline, Antigravity, Kiro, Windsurf, Copilot, Codex)
+Cline, Antigravity, Kiro, Windsurf, Copilot, Gemini, Codex)
 
 Options:
   -h, --help         display help for command
@@ -29,15 +29,15 @@ into a project for a coding agent
 
 Options:
   --target <t>    Agent target(s): claude, cursor, cline, antigravity, kiro,
-                  windsurf, copilot, codex (comma-separated or repeated)
-                  (default: [])
+                  windsurf, copilot, gemini, codex (comma-separated or
+                  repeated) (default: [])
   --skill <name>  Skill(s) to install: testsprite-verify, testsprite-onboard
                   (comma-separated or repeated; default: all) (default: [])
   --dir <path>    Project root to write into (default: cwd)
   --force         For own-file targets: overwrite existing file (a .bak backup
-                  is kept). For codex (managed-section): replaces the section
-                  unconditionally; user content outside the section is never
-                  destroyed.
+                  is kept). For managed-section targets (codex, gemini):
+                  replaces the section unconditionally; user content outside
+                  the section is never destroyed.
   -h, --help      display help for command
 
 Global options (--dry-run, --output, --profile, --endpoint-url, --request-timeout, --verbose, --debug):
@@ -116,8 +116,8 @@ Options:
   --from-env            Read TESTSPRITE_API_KEY from the environment instead of
                         prompting (default: false)
   --agent <target>      Coding-agent target to install: claude, antigravity,
-                        cursor, cline, kiro, windsurf, copilot, codex (default:
-                        claude) (default: "claude")
+                        cursor, cline, kiro, windsurf, copilot, gemini, codex
+                        (default: claude) (default: "claude")
   --no-agent            Skip the agent skill install (configure credentials
                         only)
   --force               Overwrite an existing skill file (a .bak backup is
@@ -764,7 +764,7 @@ Commands:
   test                         Inspect TestSprite tests
   agent                        Install TestSprite guidance into coding-agent
                                config (Claude Code, Cursor, Cline, Antigravity,
-                               Kiro, Windsurf, Copilot, Codex)
+                               Kiro, Windsurf, Copilot, Gemini, Codex)
   usage|credits                Show credit balance and plan/entitlement info
                                (proactive pre-flight before a large test run)
   doctor                       Diagnose CLI setup: version, Node, profile,