feat(cli): support Antigravity CLI as a flat host

[tkman59]

Problem to solve

Teams moving from Gemini CLI to Antigravity CLI (agy) have no AIDD installation: no profile writes the files agy reads.

Proposed solution

Add an isolated antigravity flat profile, modelled on Kilo, for the agy CLI in project scope. It writes skills, the memory hook and agents under .agents/, from the same source as every other host.

Content type

• Plugin

Target tool(s)

• Other: Google Antigravity CLI (agy)

Additional context

• Google moved individual Gemini CLI users to Antigravity CLI on June 18, 2026 (announcement). feat(cli): add Gemini CLI as a build target and registry citizen #623 (Gemini) stays reference material only.
• Surfaces measured on agy 1.2.14: see the spike comment.
• Hooks go in .agents/hooks.json, never settings.json (fix(aidd-context): the memory hook wired into ~/.gemini/settings.json never runs under Antigravity, and fails silently #890).
• Agent shape and frontmatter rules from feat(cli): emit portable Markdown agents under .agents/agents #916.

Acceptance criteria

• aidd setup --ai antigravity writes AIDD skills under .agents/skills/, and agy expands each as a skill (log line expanded slash command). → feat(cli): add Antigravity CLI as a flat host for skills #957 (skills, expansion measured on 1.2.14), docs: list antigravity cli as a supported flat host, with a local runtime smoke #961 (pnpm smoke:antigravity on 1.2.17)
• The memory hook is written to .agents/hooks.json under SessionStart and fires on a new session. → feat(cli): merge plugin hooks into antigravity's .agents/hooks.json #958 (format, cwd measured), docs: list antigravity cli as a supported flat host, with a local runtime smoke #961 (smoke: loaded 1 named hooks, AGENTS.md refreshed)
• Agents are written to .agents/agents/<name>/agent.md with name, description, model: inherit and tools as a YAML list, and agy loads them. → feat(cli): emit antigravity agents as portable .agents/agents/<name>/agent.md #960, docs: list antigravity cli as a supported flat host, with a local runtime smoke #961 (smoke: /agents lists aidd-dev-executor)
• aidd translate --to antigravity --as flat produces the same tree; a new antigravity:flat golden cell is added and no existing cell changes. → feat(cli): add Antigravity CLI as a flat host for skills #957 (cell added), feat(cli): merge plugin hooks into antigravity's .agents/hooks.json #958 and feat(cli): emit antigravity agents as portable .agents/agents/<name>/agent.md #960 (only that cell moves)
• clean and restore touch only AIDD-written files; other user files under .agents/ are left alone. → clean: feat(cli): add Antigravity CLI as a flat host for skills #957, feat(cli): merge plugin hooks into antigravity's .agents/hooks.json #958 (foreign named hooks kept). restore (sync --force): test(cli): prove sync restores only what antigravity setup wrote #962, both in antigravity-foreign-files.e2e.test.ts
• Tool-specific code lives in profiles/antigravity/; architecture tests pass. → feat(cli): add Antigravity CLI as a flat host for skills #957, feat(cli): merge plugin hooks into antigravity's .agents/hooks.json #958, feat(cli): emit antigravity agents as portable .agents/agents/<name>/agent.md #960 (the shared portable-agent.ts format sits in tools/domain/formats/ by design, for feat(cli): emit portable Markdown agents under .agents/agents #916)

Out of scope

• Native plugin mode (plugin.json, agy plugin install).
• Telemetry journal host (the feat(cli): support a single-clone global install shared by several CLIs #859 patch).
• Antigravity 2.0 (IDE).
• Gemini migration guide.
• Plugin files shared between two flat tools (separate bug, related to spike(framework): define the portability boundary for agent artifacts #929).

[blafourcade]

#511 now targets Antigravity. The Gemini work in #623 remains reference material, not a delivery dependency.

[tkman59]

#623 closed without merging, as Gemini CLI no longer serves individual accounts since June 18, 2026 (Google announcement).

Antigravity work will start on a new branch from main. #623 stays reference material only and is not a delivery dependency.

[blafourcade]

Evidence transferred from the concluded #859 spike:

• Antigravity agy 1.2.5 loads project customizations from <project>/.agents/ and machine-wide hooks from ~/.gemini/config/hooks.json.
• Project hooks under <project>/.agents/hooks.json activate after folder trust. --add-dir alone is not equivalent to granting trust.
• The telemetry mapping is direct: SessionStart → session-start, Stop → turn-end, and PostToolUse → tool-used.
• Repository resolution must use workspacePaths[0], not the hook process cwd. The shared readCwd defect was fixed by merged PR fix(telemetry): resolve the repository from the host, not from payload.cwd #892.
• The reusable diagnostics are the Antigravity cli-*.log hook-load count and agy -p "/hooks"; agy plugin validate alone is not runtime evidence.
• For agents, the cross-host portable shape proven with Kimi Code is .agents/agents/<name>/agent.md. A flat <name>.md can validate successfully while Antigravity silently ignores it. feat(cli): emit portable Markdown agents under .agents/agents #916 owns that shared distribution slice.

This evidence refines #511's install and lifecycle contract. #890 separately owns the inert memory-hook wiring defect. Global configuration mutation remains a product decision of the Antigravity delivery, not a generic installer assumption inherited from #859.

[dkp-consult]

@tkman59 — you own this and I'm not looking to take any of it. Just leaving what I measured during #859, in case it saves you a few evenings.

blafourcade already transferred the findings above, so I'll only add what isn't in the thread yet. I have a working antigravity journal host for aidd-telemetry, proven over the wire in both scopes — project <repo>/.agents/hooks.json and machine-wide ~/.gemini/config/hooks.json. It is detectHost on conversationId + transcriptPath, the repo resolved from workspacePaths[0], the 1:1 event mapping, a write_to_file / TargetFile extractor, and the skill step read off the SKILL.md its invocation opens — with five fixtures captured from real agy 1.2.5 sessions and three tests of its own.

It is written as a delta on the Kimi Code journal host from the same spike, which is the one caveat worth stating up front. I re-ran the bench today on 83b0246e: the journal suite goes 197 → 201 (Kimi) → 207, and the thirteen telemetry suites 310 → 314 → 320, everything passing.

Against next at d6a88809, applied after the Kimi patch, exactly one hunk no longer applies: file-writes.cjs:104, which is the readCwd fix that landed separately as #892. Dropping it is the whole rebase.

It's yours to take, adapt or ignore, and it carries no claim on the issue. Say the word and I'll push the branch or paste the diff here; if you'd rather write it your own way, the evidence in #859 is all you need and I'll stay out of your way.

Two things I got wrong last round, worth knowing before you trust anything of mine: I first reported that agy had no project hook scope — wrong namespace, the customization root is .agents/, not .gemini/ or .agy/ — and that workspacePaths was always empty, which is true only of -p without --add-dir.

[tkman59]

Spike on agy 1.2.14, run locally. Each result is backed by a log line or a hook marker, not by the model's answer.

Surface	Result
Flat skill, .agents/skills/<name>/SKILL.md	works: expanded slash command "aidd-probe" (skill)
Project hooks, .agents/hooks.json	works: loaded 2 named hooks; SessionStart and PreInvocation both fire (SessionStart is missing from the docs)
Native plugin, plugin.json	works globally (agy plugin install) and per project (copied into .agents/plugins/); invoked only as /<plugin>:<skill>
CI	plugin validate, install and list run without a login; a turn needs one

In print mode (agy -p), a turn can hang after answering, even with no skill loaded. A smoke test should check the log line and the hook marker, never wait for the turn to end.

Narrowing this issue to the flat agy CLI host, in project scope:

1. Skills and the memory hook.
2. Agents, applying the rules from feat(cli): emit portable Markdown agents under .agents/agents #916 (model: inherit, tools as a YAML list).

Out of scope, to be filed separately: native plugin mode, telemetry (the #859 patch), Antigravity 2.0, the Gemini migration guide, and a bug where uninstalling one flat tool deletes plugin files another tool still declares (reproduced by a unit test; related to #929).

I will update the description and acceptance criteria to match.