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

Adds `gemini` to the supported agent-install targets. Gemini CLI reads
project-level context from a GEMINI.md file in the repo root, which is
loaded at the start of every session (always-on, no on-demand mode).

Because all installed skills share a single GEMINI.md file in the project
root, the target uses managed-section mode -- the same approach as the
codex/AGENTS.md target -- writing only a sentinel-delimited section so
any existing user content in GEMINI.md is never clobbered.

The landing path is GEMINI.md (repo root). Both testsprite-verify and
testsprite-onboard are aggregated into one managed section, consistent
with how codex aggregates skills into AGENTS.md.

Slots into the existing TARGETS machinery: agent list, setup --agent,
and skill-nudge install-detection all pick it up automatically. Updates
the AgentTarget union, pathFor, TARGETS, agent command description,
help text, unit tests, e2e matrix guards, and the help snapshot.

Contributes to CONTRIBUTING.md accepted target: gemini

Author: Tasfia-17

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

@@ -1062,7 +1062,7 @@ 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 +1072,7 @@ 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 +1086,7 @@ 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

@@ -82,7 +82,7 @@ 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 +91,7 @@ describe('TARGETS', () => {
       'codex',
       'copilot',
       'cursor',
+      'gemini',
       'kiro',
       'windsurf',
     ]);
@@ -100,11 +101,12 @@ 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 +129,9 @@ 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 +389,31 @@ 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).
+    const gemini = renderForTarget('gemini', 'testsprite-verify');
+    expect(gemini.content).toContain('testsprite test run');
+  });
+});
+
 // ---------------------------------------------------------------------------
 // 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.
    *

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,

test/e2e/agent-install.e2e.test.ts

@@ -179,8 +179,12 @@ describe('content integrity', () => {
         expect(content.startsWith('---'), `copilot: should start with ---`).toBe(true);
         expect(content).toContain("applyTo: '**'");
         expect(content).toContain('description:');
+      } else if (target === 'gemini') {
+        // GEMINI.md is plain Markdown -- no frontmatter expected.
+        expect(content.startsWith('---'), `gemini: must NOT start with ---`).toBe(false);
+        expect(content).not.toContain('applyTo:');
+        expect(content).not.toContain('trigger:');
       }
-
       // (b) branding — the renamed H1 must be present in every body variant
       expect(content).toContain('TestSprite Verification Loop');
       // The full-body intro line lives only in the FULL body; compact-body targets
@@ -219,6 +223,9 @@ describe('content integrity', () => {
       } else if (target === 'copilot') {
         expect(content.startsWith('---'), `copilot/onboard: should start with ---`).toBe(true);
         expect(content).toContain("applyTo: '**'");
+      } else if (target === 'gemini') {
+        // GEMINI.md is plain Markdown -- no frontmatter.
+        expect(content.startsWith('---'), `gemini/onboard: must NOT start with ---`).toBe(false);
       }
 
       // Load-bearing onboard string: the skill body must reference setup
@@ -264,8 +271,38 @@ describe('content integrity', () => {
     // (d) No frontmatter fence — AGENTS.md is plain prose
     expect(content.startsWith('---'), 'codex: must NOT start with ---').toBe(false);
   });
-});
 
+  it('gemini GEMINI.md contains ONE managed section with verify and onboard content', () => {
+    const tmpDir = freshTmpDir();
+    runCli(['agent', 'install', '--target=gemini', '--dir', tmpDir, '--output', 'json']);
+
+    const filePath = join(tmpDir, TARGETS.gemini.path);
+    const content = readFileSync(filePath, 'utf8');
+
+    // (a) Exactly ONE pair of sentinels
+    const escRe = (s: string) => s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+    const beginCount = (content.match(new RegExp(escRe(MANAGED_SECTION_BEGIN), 'g')) ?? []).length;
+    const endCount = (content.match(new RegExp(escRe(MANAGED_SECTION_END), 'g')) ?? []).length;
+    expect(beginCount, 'exactly one BEGIN sentinel').toBe(1);
+    expect(endCount, 'exactly one END sentinel').toBe(1);
+
+    // BEGIN must come before END
+    expect(content.indexOf(MANAGED_SECTION_BEGIN)).toBeLessThan(
+      content.indexOf(MANAGED_SECTION_END),
+    );
+
+    // (b) Load-bearing command strings from the compact verify body
+    expect(content).toContain('testsprite test run');
+    expect(content).toContain('--wait');
+    expect(content).toContain('test artifact get');
+
+    // (c) Onboard one-liner must be present
+    expect(content).toContain('First-time setup');
+
+    // (d) No frontmatter fence -- GEMINI.md is plain prose
+    expect(content.startsWith('---'), 'gemini: must NOT start with ---').toBe(false);
+  });
+});
 // ---------------------------------------------------------------------------
 // 3. Idempotent re-run
 // ---------------------------------------------------------------------------
@@ -811,7 +848,7 @@ describe('agent list', () => {
     }>;
     expect(Array.isArray(parsed)).toBe(true);
 
-    // Expected: 8 targets × 2 skills = 16 rows
+    // Expected: targets x 2 skills per target = total rows (computed dynamically)
     const expectedCount = Object.keys(TARGETS).length * DEFAULT_SKILLS.length;
     expect(parsed.length).toBe(expectedCount);
 
@@ -848,6 +885,7 @@ describe('matrix coverage guard', () => {
       'kiro',
       'windsurf',
       'copilot',
+      'gemini',
       'codex',
     ]);
   });

test/e2e/setup.e2e.test.ts

@@ -230,6 +230,7 @@ describe('matrix coverage guard', () => {
       'kiro',
       'windsurf',
       'copilot',
+      'gemini',
       'codex',
     ]);
   });