feat(plugins): integrate portable Agent Plugins

nanobot/agent/loop.py

@@ -485,6 +485,8 @@ class AgentLoop:
             config,
             provider_snapshot_loader,
         )
+        from nanobot.agent.plugins import agent_plugin_mcp_servers
+
         return cls(
             bus=bus,
             provider=provider,
@@ -499,7 +501,7 @@ class AgentLoop:
             provider_retry_mode=defaults.provider_retry_mode,
             tool_hint_max_length=defaults.tool_hint_max_length,
             restrict_to_workspace=config.tools.restrict_to_workspace,
-            mcp_servers=config.tools.mcp_servers,
+            mcp_servers=agent_plugin_mcp_servers(config.workspace_path, config.tools.mcp_servers),
             channels_config=config.channels,
             timezone=defaults.timezone,
             unified_session=defaults.unified_session,

nanobot/agent/plugins.py

@@ -0,0 +1,361 @@
+"""Load and activate locally installed Agent Plugin packages."""
+
+from __future__ import annotations
+
+import base64
+import json
+import re
+from dataclasses import dataclass, replace
+from hashlib import sha256
+from pathlib import Path
+from typing import cast
+
+from loguru import logger
+from pydantic import ValidationError
+
+from nanobot.agent.skills import parse_skill_metadata, valid_skill_metadata
+from nanobot.config.loader import get_config_path
+from nanobot.config.schema import MCPServerConfig
+
+AGENT_PLUGIN_SCHEMA = "https://agent-plugins.org/schemas/1.0.0/plugin.schema.json"
+AGENT_PLUGIN_MCP_SCHEMA = "https://agent-plugins.org/schemas/1.0.0/mcp.schema.json"
+
+_PLUGIN_NAME = re.compile(r"^(?!.*(?:--|\.\.))[a-z0-9](?:[a-z0-9.-]*[a-z0-9])?$")
+_MCP_SERVER_FIELDS = {"type", "command", "args", "env", "cwd"}
+_MAX_LOGO_BYTES = 256 * 1024
+
+
+@dataclass(frozen=True)
+class AgentPlugin:
+    """A validated, locally installed Agent Plugins v1 package."""
+
+    name: str
+    root: Path
+    description: str
+    repository: str
+    display_name: str
+    category: str
+    accent_color: str | None
+    logo: str | None
+    permissions: tuple[str, ...]
+    mcp_servers: tuple[str, ...] = ()
+    enabled: bool = False
+
+
+def _installed_plugins(workspace: Path) -> list[AgentPlugin]:
+    """Return installed packages found under ``<workspace>/plugins/*``."""
+    workspace = workspace.expanduser().resolve()
+    root = _contained(workspace / "plugins", workspace, directory=True)
+    if root is None:
+        return []
+    plugins: dict[str, AgentPlugin | None] = {}
+    for candidate in _children(root, "Agent Plugins directory"):
+        plugin_root = _contained(candidate, root, directory=True)
+        if plugin_root is None:
+            continue
+        plugin = _load_manifest(plugin_root)
+        if plugin is not None:
+            if plugin.name in plugins:
+                logger.warning("Ignoring duplicate Agent Plugin identity '{}'", plugin.name)
+                plugins[plugin.name] = None
+            else:
+                plugins[plugin.name] = plugin
+    return [plugin for plugin in plugins.values() if plugin is not None]
+
+
+def enabled_agent_plugin_skills(workspace: Path) -> list[tuple[str, Path]]:
+    """Return skills from plugins the user has explicitly enabled."""
+    return [
+        skill
+        for plugin in _installed_plugins(workspace)
+        if _enabled(workspace, plugin)
+        for skill in _discover_plugin_skills(plugin.name, plugin.root)
+    ]
+
+
+def _load_manifest(plugin_root: Path) -> AgentPlugin | None:
+    payload = _read_object(plugin_root / "plugin.json", plugin_root)
+    if payload is None:
+        return None
+    if payload.get("$schema") != AGENT_PLUGIN_SCHEMA:
+        return None
+    name = payload.get("name")
+    if (
+        not isinstance(name, str)
+        or len(name) > 64
+        or _PLUGIN_NAME.fullmatch(name) is None
+    ):
+        logger.warning("Ignoring Agent Plugin manifest in '{}': invalid name", plugin_root)
+        return None
+    extension = payload.get("extensions")
+    extension_payload = cast(dict[str, object], extension) if isinstance(extension, dict) else {}
+    nanobot_value = extension_payload.get("dev.nanobot")
+    nanobot = cast(dict[str, object], nanobot_value) if isinstance(nanobot_value, dict) else {}
+    return AgentPlugin(
+        name=name,
+        root=plugin_root,
+        description=_string(payload.get("description")),
+        repository=_string(payload.get("repository")),
+        display_name=_string(nanobot.get("displayName")) or name,
+        category=_string(nanobot.get("category")) or "Plugin",
+        accent_color=_accent_color(nanobot.get("accentColor")),
+        logo=_plugin_logo(nanobot.get("logo"), plugin_root),
+        permissions=_string_tuple(nanobot.get("permissions")),
+    )
+
+
+def agent_plugin_mcp_servers(
+    workspace: Path,
+    configured: dict[str, MCPServerConfig] | None = None,
+) -> dict[str, MCPServerConfig]:
+    """Merge explicitly enabled plugin MCP servers with user configuration.
+
+    User configuration wins on the unlikely event of a namespaced collision.
+    """
+    servers: dict[str, MCPServerConfig] = {}
+    for plugin in _installed_plugins(workspace):
+        if not _enabled(workspace, plugin):
+            continue
+        plugin_servers = _plugin_mcp_servers(workspace, plugin)
+        for name, server in plugin_servers.items():
+            host_name = plugin.name if len(plugin_servers) == 1 else f"{plugin.name}-{name}"
+            servers[host_name] = server
+    configured = configured or {}
+    if collisions := servers.keys() & configured.keys():
+        logger.warning("Configured MCP servers override Agent Plugins: {}", ", ".join(sorted(collisions)))
+    return servers | configured
+
+
+def discover_agent_plugins(workspace: Path) -> list[AgentPlugin]:
+    """Return component and lifecycle state for discovered plugins."""
+    return [
+        replace(
+            plugin,
+            mcp_servers=tuple(sorted(_plugin_mcp_servers(workspace, plugin))),
+            enabled=_enabled(workspace, plugin),
+        )
+        for plugin in _installed_plugins(workspace)
+    ]
+
+
+def set_agent_plugin_enabled(workspace: Path, name: str, enabled: bool) -> None:
+    """Enable or disable one installed plugin."""
+    plugin = next((item for item in _installed_plugins(workspace) if item.name == name), None)
+    if plugin is None:
+        raise ValueError(f"unknown Agent Plugin '{name}'")
+    data = _plugin_data_dir(workspace, plugin.name, create=True)
+    marker = data / "enabled"
+    if enabled:
+        marker.write_text(str(plugin.root), encoding="utf-8")
+        marker.chmod(0o600)
+    else:
+        marker.unlink(missing_ok=True)
+
+
+def _string(value: object) -> str:
+    return value.strip() if isinstance(value, str) else ""
+
+
+def _string_tuple(value: object) -> tuple[str, ...]:
+    items = cast(list[object], value) if isinstance(value, list) else []
+    return tuple(item.strip() for item in items if isinstance(item, str) and item.strip())
+
+
+def _accent_color(value: object) -> str | None:
+    return value if isinstance(value, str) and re.fullmatch(r"#[0-9a-fA-F]{6}", value) else None
+
+
+def _plugin_logo(value: object, plugin_root: Path) -> str | None:
+    """Resolve nanobot's optional packaged logo extension."""
+    if value is None:
+        return None
+    if not isinstance(value, str) or not value.startswith("./"):
+        logger.warning("Ignoring invalid Agent Plugin logo in '{}'", plugin_root)
+        return None
+    logo = _contained(plugin_root / value[2:], plugin_root)
+    try:
+        data = logo.read_bytes() if logo is not None else b""
+        suffix = logo.suffix.lower() if logo is not None else ""
+        if len(data) <= _MAX_LOGO_BYTES and (
+            suffix == ".png" and data.startswith(b"\x89PNG\r\n\x1a\n")
+            or suffix in {".jpg", ".jpeg"} and data.startswith(b"\xff\xd8\xff")
+            or suffix == ".webp" and data.startswith(b"RIFF") and data[8:12] == b"WEBP"
+        ):
+            mime = "jpeg" if suffix in {".jpg", ".jpeg"} else suffix[1:]
+            return f"data:image/{mime};base64,{base64.b64encode(data).decode('ascii')}"
+    except OSError:
+        pass
+    logger.warning("Ignoring invalid Agent Plugin logo in '{}'", plugin_root)
+    return None
+
+
+def _plugin_mcp_servers(workspace: Path, plugin: AgentPlugin) -> dict[str, MCPServerConfig]:
+    payload = _read_object(plugin.root / "mcp.json", plugin.root)
+    if payload is None:
+        return {}
+    raw_servers = payload.get("mcpServers")
+    if (
+        payload.keys() != {"$schema", "mcpServers"}
+        or payload.get("$schema") != AGENT_PLUGIN_MCP_SCHEMA
+        or not isinstance(raw_servers, dict)
+    ):
+        logger.warning("Ignoring invalid MCP component for Agent Plugin '{}'", plugin.name)
+        return {}
+
+    data = _plugin_data_dir(workspace, plugin.name, create=True)
+    servers: dict[str, MCPServerConfig] = {}
+    for name, raw in cast(dict[str, object], raw_servers).items():
+        if not name or len(name) > 128 or any(ord(char) < 32 for char in name):
+            logger.warning("Ignoring invalid MCP server name in Agent Plugin '{}'", plugin.name)
+            continue
+        server = _plugin_mcp_server(raw, plugin.root, data)
+        if server is None:
+            logger.warning("Ignoring invalid MCP server '{}' in Agent Plugin '{}'", name, plugin.name)
+            continue
+        servers[name] = server
+    return servers
+
+
+def _plugin_mcp_server(raw: object, root: Path, data: Path) -> MCPServerConfig | None:
+    if not isinstance(raw, dict):
+        return None
+    payload = cast(dict[str, object], raw)
+    if payload.keys() - _MCP_SERVER_FIELDS:
+        return None
+    try:
+        server = MCPServerConfig.model_validate(payload)
+    except ValidationError:
+        return None
+    command = _stdio_command(server.command, root)
+    cwd = _stdio_cwd(payload.get("cwd"), root, data)
+    if server.type != "stdio" or command is None or cwd is None:
+        return None
+    if {"PLUGIN_ROOT", "PLUGIN_DATA"} & server.env.keys():
+        return None
+    return server.model_copy(
+        update={
+            "command": command,
+            "args": [_expand(item, root, data) for item in server.args],
+            "env": {
+                **{key: _expand(value, root, data) for key, value in server.env.items()},
+                "PLUGIN_ROOT": str(root),
+                "PLUGIN_DATA": str(data),
+            },
+            "cwd": str(cwd),
+        }
+    )
+
+
+def _stdio_command(value: object, root: Path) -> str | None:
+    if not isinstance(value, str) or not value:
+        return None
+    if value.startswith("./"):
+        executable = _contained(root / value[2:], root)
+        return str(executable) if executable is not None else None
+    if any(char.isspace() for char in value) or "/" in value or "\\" in value:
+        return None
+    return value
+
+
+def _stdio_cwd(value: object, root: Path, data: Path) -> Path | None:
+    if value is None:
+        return root
+    if not isinstance(value, str):
+        return None
+    if value.startswith("./"):
+        return _contained(root / value[2:], root, directory=True)
+    for placeholder, base in (("${PLUGIN_ROOT}", root), ("${PLUGIN_DATA}", data)):
+        if value == placeholder or value.startswith(f"{placeholder}/"):
+            relative = value[len(placeholder):].lstrip("/")
+            candidate = (base / relative).resolve()
+            if not candidate.is_relative_to(base):
+                return None
+            if base == data:
+                candidate.mkdir(parents=True, exist_ok=True)
+                candidate.chmod(0o700)
+            return candidate if candidate.is_dir() else None
+    return None
+
+
+def _expand(value: str, root: Path, data: Path) -> str:
+    return value.replace("${PLUGIN_ROOT}", str(root)).replace("${PLUGIN_DATA}", str(data))
+
+
+def _plugin_data_dir(workspace: Path, name: str, *, create: bool) -> Path:
+    workspace_id = sha256(str(workspace.expanduser().resolve()).encode()).hexdigest()[:12]
+    current = get_config_path().expanduser().resolve().parent
+    for segment in ("plugin-data", workspace_id, name):
+        path = current / segment
+        if create:
+            path.mkdir(parents=True, exist_ok=True)
+        try:
+            resolved = path.resolve(strict=create)
+        except OSError as exc:
+            raise RuntimeError("Agent Plugin data directory is unavailable") from exc
+        if not resolved.is_relative_to(current):
+            raise RuntimeError("Agent Plugin data directory escapes its parent")
+        if create:
+            resolved.chmod(0o700)
+        current = resolved
+    return current
+
+
+def _enabled(workspace: Path, plugin: AgentPlugin) -> bool:
+    marker = _plugin_data_dir(workspace, plugin.name, create=False) / "enabled"
+    try:
+        return marker.is_file() and marker.read_text(encoding="utf-8") == str(plugin.root)
+    except OSError:
+        return False
+
+
+def _discover_plugin_skills(plugin_name: str, plugin_root: Path) -> list[tuple[str, Path]]:
+    skills_root = _contained(plugin_root / "skills", plugin_root, directory=True)
+    if skills_root is None:
+        return []
+
+    skills: list[tuple[str, Path]] = []
+    for candidate in _children(skills_root, f"Agent Plugin '{plugin_name}' skills"):
+        skill_root = _contained(candidate, skills_root, directory=True)
+        if skill_root is None:
+            continue
+        skill_file = _contained(skill_root / "SKILL.md", plugin_root)
+        if skill_file is None:
+            continue
+        try:
+            metadata = parse_skill_metadata(skill_file.read_text(encoding="utf-8"))
+        except (OSError, UnicodeError):
+            metadata = None
+        if metadata is None or not valid_skill_metadata(metadata, candidate.name):
+            logger.warning("Ignoring Agent Plugin '{}' skill '{}': invalid metadata", plugin_name, candidate.name)
+            continue
+        skills.append((candidate.name, skill_file))
+    return skills
+
+
+def _children(root: Path, label: str) -> list[Path]:
+    try:
+        return sorted(root.iterdir(), key=lambda path: path.name)
+    except OSError as exc:
+        logger.warning("Could not inspect {}: {}", label, exc)
+        return []
+
+
+def _contained(path: Path, root: Path, *, directory: bool = False) -> Path | None:
+    try:
+        resolved = path.resolve(strict=True)
+    except OSError:
+        return None
+    expected_kind = resolved.is_dir() if directory else resolved.is_file()
+    return resolved if expected_kind and resolved.is_relative_to(root) else None
+
+
+def _read_object(path: Path, root: Path) -> dict[str, object] | None:
+    contained = _contained(path, root)
+    if contained is None:
+        return None
+    try:
+        value = cast(object, json.loads(contained.read_text(encoding="utf-8")))
+    except (OSError, UnicodeError, json.JSONDecodeError) as exc:
+        logger.warning("Ignoring invalid Agent Plugin component '{}': {}", contained, exc)
+        return None
+    return cast(dict[str, object], value) if isinstance(value, dict) else None

nanobot/agent/skills.py

@@ -17,9 +17,35 @@ _STRIP_SKILL_FRONTMATTER = re.compile(
     r"^---\s*\r?\n(.*?)\r?\n---\s*\r?\n?",
     re.DOTALL,
 )
+_SKILL_NAME = re.compile(r"^(?!.*--)[a-z0-9](?:[a-z0-9-]*[a-z0-9])?$")
 _SKILL_REFERENCE = re.compile(r"(?<![\w$])\$([A-Za-z0-9_-]+)")
 
 
+def parse_skill_metadata(content: str) -> dict[str, object] | None:
+    """Parse a skill document's YAML frontmatter."""
+    if not (match := _STRIP_SKILL_FRONTMATTER.match(content)):
+        return None
+    try:
+        parsed = yaml.safe_load(match.group(1))
+    except yaml.YAMLError:
+        return None
+    if not isinstance(parsed, dict):
+        return None
+    return {str(key): value for key, value in cast(dict[object, object], parsed).items()}
+
+
+def valid_skill_metadata(metadata: dict[str, object], name: str) -> bool:
+    """Return whether metadata satisfies the Agent Skills identity contract."""
+    description = metadata.get("description")
+    return (
+        metadata.get("name") == name
+        and len(name) <= 64
+        and _SKILL_NAME.fullmatch(name) is not None
+        and isinstance(description, str)
+        and 1 <= len(description.strip()) <= 1024
+    )
+
+
 class SkillsLoader:
     """
     Loader for agent skills.
@@ -34,6 +60,15 @@ class SkillsLoader:
         self.builtin_skills = builtin_skills_dir or BUILTIN_SKILLS_DIR
         self.disabled_skills = disabled_skills or set()
 
+    def _skill_aliases(self) -> dict[str, str]:
+        """Return compatibility aliases owned by installed CLI Apps."""
+        from nanobot.apps.cli import CliAppManager
+
+        try:
+            return CliAppManager(workspace=self.workspace).installed_skill_aliases()
+        except OSError:
+            return {}
+
     def _skill_entries_from_dir(self, base: Path, source: str, *, skip_names: set[str] | None = None) -> list[dict[str, str]]:
         if not base.exists():
             return []
@@ -60,15 +95,33 @@ class SkillsLoader:
         Returns:
             List of skill info dicts with 'name', 'path', 'source'.
         """
+        from nanobot.agent.plugins import enabled_agent_plugin_skills
+
+        plugin_skills = enabled_agent_plugin_skills(self.workspace)
         skills = self._skill_entries_from_dir(self.workspace_skills, "workspace")
-        workspace_names = {entry["name"] for entry in skills}
+        seen_names = {entry["name"] for entry in skills}
+        for name, path in plugin_skills:
+            if name in seen_names:
+                continue
+            skills.append(
+                {
+                    "name": name,
+                    "path": str(path),
+                    "source": "plugin",
+                }
+            )
+            seen_names.add(name)
         if self.builtin_skills and self.builtin_skills.exists():
             skills.extend(
-                self._skill_entries_from_dir(self.builtin_skills, "builtin", skip_names=workspace_names)
+                self._skill_entries_from_dir(self.builtin_skills, "builtin", skip_names=seen_names)
             )
 
         if self.disabled_skills:
-            skills = [s for s in skills if s["name"] not in self.disabled_skills]
+            disabled = set(self.disabled_skills)
+            for legacy, canonical in self._skill_aliases().items():
+                if legacy in disabled or canonical in disabled:
+                    disabled.update((legacy, canonical))
+            skills = [s for s in skills if s["name"] not in disabled]
 
         if filter_unavailable:
             return [skill for skill in skills if self._check_requirements(self._get_skill_meta(skill["name"]))]
@@ -84,14 +137,11 @@ class SkillsLoader:
         Returns:
             Skill content or None if not found.
         """
-        roots = [self.workspace_skills]
-        if self.builtin_skills:
-            roots.append(self.builtin_skills)
-        for root in roots:
-            path = root / name / "SKILL.md"
-            if path.exists():
-                return path.read_text(encoding="utf-8")
-        return None
+        skills = self.list_skills(filter_unavailable=False)
+        available = {skill["name"] for skill in skills}
+        resolved = name if name in available else self._skill_aliases().get(name, name)
+        entry = next((skill for skill in skills if skill["name"] == resolved), None)
+        return Path(entry["path"]).read_text(encoding="utf-8") if entry else None
 
     def load_skills_for_context(self, skill_names: list[str]) -> str:
         """
@@ -118,9 +168,11 @@ class SkillsLoader:
             entry["name"]
             for entry in self.list_skills(filter_unavailable=True)
         }
+        aliases = self._skill_aliases()
         invoked: list[str] = []
         for match in _SKILL_REFERENCE.finditer(text):
-            name = match.group(1)
+            requested = match.group(1)
+            name = requested if requested in available else aliases.get(requested, requested)
             if name in available and name not in invoked:
                 invoked.append(name)
         return invoked
@@ -145,6 +197,7 @@ class SkillsLoader:
         sections: list[str] = []
         groups = (
             ("Workspace skills", "workspace", self.workspace_skills),
+            ("Agent Plugin skills", "plugin", self.workspace / "plugins"),
             ("Built-in skills", "builtin", self.builtin_skills),
         )
         for label, source, root in groups:
@@ -278,21 +331,4 @@ class SkillsLoader:
         Returns:
             Metadata dict or None.
         """
-        content = self.load_skill(name)
-        if not content or not content.startswith("---"):
-            return None
-        match = _STRIP_SKILL_FRONTMATTER.match(content)
-        if not match:
-            return None
-        try:
-            parsed = yaml.safe_load(match.group(1))
-        except yaml.YAMLError:
-            return None
-        if not isinstance(parsed, dict):
-            return None
-        # yaml.safe_load returns native types (int, bool, list, etc.);
-        # keep values as-is so downstream consumers get correct types.
-        metadata: dict[str, object] = {}
-        for key, value in cast(dict[object, object], parsed).items():
-            metadata[str(key)] = value
-        return metadata
+        return parse_skill_metadata(self.load_skill(name) or "")

nanobot/agent/tools/mcp.py

@@ -1340,10 +1340,14 @@ async def reload_servers(state: Any, registry: ToolRegistry) -> dict[str, Any]:
                 "requires_restart": True,
             }
         try:
+            from nanobot.agent.plugins import agent_plugin_mcp_servers
             from nanobot.config.loader import load_config, resolve_config_env_vars
 
             config = resolve_config_env_vars(load_config())
-            next_servers = dict(config.tools.mcp_servers)
+            next_servers = agent_plugin_mcp_servers(
+                config.workspace_path,
+                config.tools.mcp_servers,
+            )
         except Exception as exc:
             logger.warning("MCP hot reload could not read config: {}", exc)
             return {