Agy MCP Plugins

agy-mcp-plugins

Wire MCP servers and package/install plugins into Google's Antigravity (AGY) image so an AGY worker can reach the flywheel substrate (Agent-Mail, the br/beads bridge) and run the AgentOps corpus in its own harness. Sibling of agy-native, which drives the loop; this skill supplies the tool surface that loop runs against.

Overview / When to Use

AGY's extension surface is plugins — a plugin tree (plugin.json + skills/, subagents/, hooks.json, and a mcpServers declaration) imported, validated, and enabled through agy plugin {import,validate,install,enable,disable,uninstall,link,list}. MCP servers reach AGY through that plugin model (declared in a plugin's mcpServers, or via the AGY settings at ~/.gemini/settings.json), not through a standalone gemini-cli mcp subcommand. A bare SKILL.md under ~/.gemini/skills/ is portable and needs no plugin.json just to expose a skill — but a tool server must be declared, enabled, and reachable before any skill that depends on it runs.

Use this skill when standing up the AGY lane in the flywheel, when a freshly built MCP server must become reachable to an AGY worker, or when distributing the AgentOps bundle to AGY as a plugin.

This is operator-side: it drives the flywheel harness. Never surface these commands or this framing in client-facing AI Partner content.

AGY ≠ gemini-cli. Do not reach for gemini mcp, gemini extensions, or gemini -p — those belong to the retired gemini-cli image. AGY's runtime is agy / agy -p, and its extension unit is the plugin.

⚠️ Critical Constraints

• Rule 1 — Verify the live surface first. Run agy plugin help (and agy plugin <sub> --help) before acting. Why: the subcommand shape shifts between Antigravity releases; acting on a remembered shape silently writes a malformed plugin or settings entry that breaks later agy runs.
• Rule 2 — List before and after every mutation. Run agy plugin list before and after import/install/enable/disable. Why: the effective tool surface is the list output, not the command you believed you ran.
• Rule 3 — Declare only scoped MCP servers. Register only the servers the AGY task actually needs (Agent-Mail, the br bridge, a specific connector). Why: every registered server widens the tool blast radius an AGY worker can call.
• Rule 4 — Disable before uninstall when uncertain. Prefer agy plugin disable <name> as the reversible first step over uninstall. Why: uninstalling a working plugin destroys config that may belong to another lane; disable is recoverable.
• Rule 5 — Never inline secrets. Declare MCP tokens by env-var reference in the plugin's mcpServers / settings, never as a literal in a tracked file. Why: plugin.json and ~/.gemini/settings.json are plaintext and often synced across the fleet — an inlined token leaks everywhere.
• Rule 6 — Keep the dcg guard wired. ~/.gemini/settings.json carries a BeforeTool → dcg hook on run_shell_command; do not remove or shadow it when adding plugins/servers. Why: it blocks destructive commands that an auto-approved AGY worker would otherwise run.
• Rule 7 — Operator-side; invoke-never-rebuild. Drive agy; do not re-author AGY, do not write under ~/dev/agentops, do not push agentops. Why: AGY is Emanuel's substrate — own a thin adapter, not the tool.

Workflow / Methodology

Phase 1: Inventory the current surface

agy plugin help               # confirm the live subcommand shape (Rule 1)
agy plugin list               # installed plugins + enabled state (the BEFORE list)

Record installed plugins, their enabled state, and any MCP servers already declared in ~/.gemini/settings.json / enabled plugins. Checkpoint: the target plugin/server name is NOT already present, OR you have decided repair vs. leave-as-is. Do not blind-add over an existing name.

Phase 2: Declare an MCP server (the tool-reach path)

AGY reaches an MCP server through a plugin's mcpServers declaration (or the AGY settings). A minimal plugin tree exposing one server:

agy-tools/
  plugin.json     # { "name":"agy-tools", "version":"0.1.0",
                  #   "mcpServers": { "agent-mail": { "command":"mcp-agent-mail" },
                  #     "beads-br": { "command":"br", "args":["mcp"],
                  #                   "env": { "BR_DB": "$BR_DB" } } } }

For a remote/HTTP MCP, declare its url and a *_ENV_VAR token reference (never the literal token — Rule 5). Validate, then install + enable:

agy plugin validate ./agy-tools
agy plugin install ./agy-tools     # reads plugin.json (or name@marketplace)
agy plugin enable agy-tools
agy plugin list                    # the AFTER list — server-bearing plugin enabled

Checkpoint: agy plugin list shows the plugin enabled; the declared server appears in the effective surface with the expected scope.

Phase 3: Ship a plugin bundle (the distribution path)

Distribute the AgentOps bundle the AGY-native way — import an existing tree or install from a plugin.json / marketplace reference:

agy plugin import claude            # pull an existing Claude plugin tree into AGY
agy plugin import gemini            # or an existing gemini plugin tree
agy plugin validate ./agentops-bundle
agy plugin install ./agentops-bundle        # local tree
agy plugin install agentops@<marketplace>   # or a marketplace reference
agy plugin enable agentops

Portable-skill note: the corpus already lives at ~/.gemini/skills/<name>/SKILL.md and AGY reads SKILL.md directly — no plugin.json is needed just to expose a skill; the plugin path is for servers, subagents, hooks, and bundled distribution. Checkpoint: agy plugin list shows the bundle installed and enabled from the expected source.

Phase 4: Smoke-test the tool surface

Run a read-only AGY worker that exercises the wiring; capture output and exit code:

agy -p --add-dir "$REPO" \
  "List your available MCP tools and call one safe read-only tool. Do not edit."

Checkpoint: the worker enumerates the expected servers and reaches at least one tool. The config is not "wired" until a worker actually uses it.

Output Specification

Format: plugin/MCP wiring on the AGY image + machine-/human-readable verification output. Filename / path: plugin trees live in their own dirs (plugin.json owns the declaration); AGY-global MCP/hook settings live in ~/.gemini/settings.json (let agy plugin own plugin writes; edit settings only for AGY-global MCP/hooks). Structure: for each change report — before/after agy plugin list; plugin and server names imported/installed/enabled/disabled/uninstalled; smoke-test command + exit code; explicit rollback commands (agy plugin disable/uninstall).

Quality Rubric

• Ran agy plugin help before acting — no remembered subcommand shape (Rule 1)
• Captured before/after agy plugin list for every mutation (Rule 2)
• Declared only the MCP servers the task needs — scoped surface (Rule 3)
• Used disable before uninstall when uncertain — reversible first (Rule 4)
• No secret inlined; tokens by env-var reference in plugin/settings (Rule 5)
• dcg BeforeTool hook still present in ~/.gemini/settings.json (Rule 6)
• Nothing written under ~/dev/agentops; no agentops push (Rule 7)
• agy plugin validate passed; end-to-end verified by a real AGY worker
• No gemini-cli surface used (gemini mcp/gemini extensions/gemini -p)
• Backstage: no client-facing surface mentions these commands or framing

Examples

• Reach Agent-Mail from an AGY flywheel worker: declare agent-mail in a plugin's mcpServers, agy plugin validate && agy plugin install ./agy-tools && agy plugin enable agy-tools, then agy plugin list to confirm.
• Reach br/beads via an MCP bridge: declare beads-br with command: br, args: ["mcp"], and env.BR_DB: "$BR_DB" (env-ref, not literal).
• Ship the staged AgentOps bundle to AGY: agy plugin import claude to pull the existing tree, then agy plugin install ./agentops-bundle && agy plugin enable agentops.
• Reversible removal: agy plugin disable agy-tools (confirm via list) before agy plugin uninstall agy-tools.

Troubleshooting

See Also / References

• agy-native — drives the loop this skill supplies tools to (sibling AGY skill)
• agy plugin help, agy plugin <sub> --help — the live, authoritative surface
• agent-mail — the multi-agent coordination MCP most often wired
• beads-br — the br/beads tracker reached via an MCP bridge
• dcg — the destructive-command guard wired as AGY's BeforeTool hook
• ~/.gemini/settings.json — AGY-global MCP/hook settings backing the image