fix(#4705): emit Antigravity-native tool names as a YAML sequence (#4822)

* test(#4705): add failing-first coverage for native Antigravity tool sequences

* fix(#4705): emit Antigravity-native tool names as a YAML sequence

convertClaudeAgentToAntigravityAgent and the installer's twin emitted
Gemini CLI tool names as a comma-separated scalar. Antigravity's
documented subagent contract (antigravity.google/docs/subagents) wants a
YAML sequence of native names — view_file, grep_search, run_command,
replace_file_content are the documented examples, and wrong or malformed
grants can hang the subagent per Antigravity's own warning.

Map values move to the native vocabulary where documented (Read ->
view_file, Edit -> replace_file_content, Bash -> run_command, Grep ->
grep_search); undocumented entries keep their best-known grant rather
than being dropped (dropping would silently remove a restriction). The
emitter writes one '- name' item per line; an agent whose every tool was
filtered emits an explicit tools: [] instead of an empty scalar.
Pre-existing pins updated to the native vocabulary.

* test(#4705): update the #4727 map-value pin to the Antigravity-native vocabulary

The #4727-era pin held the map VALUES at the Gemini CLI dialect on the
belief that Antigravity speaks it; the confirmed bug #4705 (with
Antigravity's own documented subagent contract) supersedes that for the
four documented names. Key/shape pinning is preserved; only the values
move.

* docs(#4705): backfill changeset PR number

---------

Co-authored-by: sim <sim@local>

tests/gemini-runtime-removed.test.cjs

@@ -217,13 +217,14 @@ describe('#1928 Antigravity preserved (shared surface with the removed gemini ru
     assert.strictEqual(getRuntimeLabel('antigravity'), 'Antigravity');
   });
 
-  test('the shared Gemini-backend tool vocabulary still powers Antigravity agent conversion', () => {
+  test('the Antigravity-native tool vocabulary powers Antigravity agent conversion (#4705)', () => {
     const input = ['---', 'name: gsd-x', 'description: d', 'tools: Read, Write, WebFetch, Skill', '---', '', 'body'].join('\n');
-    const toolsLine = convertClaudeAgentToAntigravityAgent(input).split('\n').find((l) => l.startsWith('tools:')) || '';
-    assert.ok(toolsLine.includes('read_file'), 'Read → read_file via the retained convertAntigravityToolName');
-    assert.ok(toolsLine.includes('write_file'), 'Write → write_file');
-    assert.ok(toolsLine.includes('web_fetch'), 'WebFetch → web_fetch');
-    assert.ok(!/\bskill\b/.test(toolsLine), 'Skill is still excluded (would be an invalid backend tool name)');
+    const result = convertClaudeAgentToAntigravityAgent(input);
+    const toolsBlock = result.slice(result.indexOf('tools:')).split('\n').filter((l) => l.startsWith('- '));
+    assert.ok(toolsBlock.includes('- view_file'), 'Read → view_file (native name, #4705)');
+    assert.ok(toolsBlock.includes('- write_file'), 'Write → write_file');
+    assert.ok(toolsBlock.includes('- web_fetch'), 'WebFetch → web_fetch');
+    assert.ok(!toolsBlock.some((l) => /\bskill\b/.test(l)), 'Skill is still excluded (would be an invalid backend tool name)');
   });
 
   test('#4727 the rename is complete: no gemini-named alias survives alongside the antigravity-named exports', () => {
@@ -250,20 +251,25 @@ describe('#1928 Antigravity preserved (shared surface with the removed gemini ru
       'the retired gemini-named function must not still be exported — a surviving alias means the rename never finished',
     );
 
-    // The rename must be a pure identifier change: every value byte-identical, so an added OR
-    // removed key (not just a renamed export) fails this too.
+    // The #4727 rename remains a pure identifier change: same KEYS, same shape
+    // (an added OR removed key still fails). The VALUES moved from the Gemini
+    // CLI dialect to Antigravity-native names in #4705 — Antigravity's own
+    // documented subagent contract (antigravity.google/docs/subagents) names
+    // view_file / replace_file_content / grep_search / run_command as native,
+    // and its tool-validation warning says wrong names can hang the subagent.
+    // The old "Antigravity speaks the Gemini dialect" rationale was the belief
+    // at #4727 time; the confirmed bug #4705 supersedes it.
     assert.deepStrictEqual(mod.claudeToAntigravityTools, {
-      Read: 'read_file',
+      Read: 'view_file',
       Write: 'write_file',
-      Edit: 'replace',
-      Bash: 'run_shell_command',
+      Edit: 'replace_file_content',
+      Bash: 'run_command',
       Glob: 'glob',
-      Grep: 'search_file_content',
+      Grep: 'grep_search',
       WebSearch: 'google_web_search',
       WebFetch: 'web_fetch',
       TodoWrite: 'write_todos',
-    }, 'the tool map values are Gemini\'s built-in tool dialect, which Antigravity speaks — Google\'s '
-      + 'contract, not GSD\'s to alter by renaming the map that carries it');
+    }, 'the tool map keys are the #4727 rename surface (add/remove still fails); the VALUES are the #4705 Antigravity-native vocabulary');
 
     // In-set / out-of-set boundary pair: the excluded ids still return null individually...
     for (const excluded of ['mcp__anything', 'Task', 'Agent', 'AskUserQuestion', 'ask_user', 'Skill', 'SlashCommand']) {

tests/runtime-converters.test.cjs

@@ -478,12 +478,12 @@ tools: Read, Write, Bash, Skill, WebFetch, SlashCommand
 <role>Plan the phase.</role>`;
 
     const result = convertClaudeAgentToAntigravityAgent(input);
-    const toolsLine = result.split('\n').find(l => l.startsWith('tools:')) || '';
+    const toolsItems = result.split('\n').filter(l => l.startsWith('- ')).map(l => l.slice(2));
 
-    assert.ok(toolsLine.includes('read_file'), 'maps Read -> read_file');
-    assert.ok(toolsLine.includes('web_fetch'), 'maps WebFetch -> web_fetch');
-    assert.ok(!/\bskill\b/.test(toolsLine), 'no invalid skill tool in Antigravity frontmatter');
-    assert.ok(!/\bslashcommand\b/.test(toolsLine), 'no invalid slashcommand tool in Antigravity frontmatter');
+    assert.ok(toolsItems.includes('view_file'), 'maps Read -> view_file (#4705 native name)');
+    assert.ok(toolsItems.includes('web_fetch'), 'maps WebFetch -> web_fetch');
+    assert.ok(!toolsItems.some(t => /\bskill\b/.test(t)), 'no invalid skill tool in Antigravity frontmatter');
+    assert.ok(!toolsItems.some(t => /\bslashcommand\b/.test(t)), 'no invalid slashcommand tool in Antigravity frontmatter');
   });
 });
 
@@ -2667,3 +2667,40 @@ describe('#3706: the layout seam actually threads the variant', () => {
     }
   });
 });
+
+// ── #4705 — Antigravity agent tools: native names, YAML sequence ─────────────
+// The converter emitted Gemini CLI tool names as a comma-separated scalar;
+// Antigravity's documented subagent contract (antigravity.google/docs/subagents)
+// wants a YAML sequence of native tool names (view_file, grep_search,
+// run_command, replace_file_content are the documented examples). A scalar or a
+// wrong-vocabulary grant can hang the subagent per Antigravity's own warning.
+describe('#4705 — Antigravity agent tools are native names in a YAML sequence', () => {
+  const input = `---
+name: example-reviewer
+description: Inspect source files
+tools: Read, Grep, Bash
+---
+
+Inspect source files.`;
+
+  test('emits the documented native tools as a YAML sequence (#4705)', () => {
+    const result = convertClaudeAgentToAntigravityAgent(input);
+    assert.match(result, /tools:\n- view_file\n- grep_search\n- run_command\n/,
+      'tools must be a YAML sequence of Antigravity-native names (view_file, grep_search, run_command)');
+    assert.doesNotMatch(result, /tools:.*,/m, 'no comma-separated scalar may survive');
+  });
+
+  test('Edit maps to the documented replace_file_content (#4705)', () => {
+    const result = convertClaudeAgentToAntigravityAgent(
+      `---\nname: e\ndescription: d\ntools: Edit\n---\n\nbody`);
+    assert.match(result, /- replace_file_content/, 'Edit -> replace_file_content (documented native name)');
+    assert.ok(!/- replace\b/.test(result), 'the Gemini CLI name replace must not survive');
+  });
+
+  test('unmapped tools keep their lowercase grant (no silent restriction drop) (#4705)', () => {
+    const result = convertClaudeAgentToAntigravityAgent(
+      `---\nname: e\ndescription: d\ntools: Glob, WebFetch\n---\n\nbody`);
+    assert.match(result, /- glob/, 'undocumented tools keep their mapped/lowercase grant');
+    assert.match(result, /- web_fetch/, 'WebFetch stays granted');
+  });
+});