Use bare ${CLAUDE_PLUGIN_ROOT} so the server launches from the plugin directory

harbor-mcp/.claude-plugin/plugin.json

@@ -1,12 +1,18 @@
 {
   "name": "harbor-mcp",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "description": "MCP server for the Harbor hub: inspect evaluation jobs, trials, and uploads; publish tasks and datasets when writes are enabled.",
   "author": {
     "name": "Walker Hughes"
   },
   "license": "MIT",
   "homepage": "https://github.com/walkerhughes/mcps/tree/main/harbor-mcp",
   "repository": "https://github.com/walkerhughes/mcps",
-  "keywords": ["harbor", "evals", "mcp", "evaluation", "llm"]
+  "keywords": [
+    "harbor",
+    "evals",
+    "mcp",
+    "evaluation",
+    "llm"
+  ]
 }

harbor-mcp/.mcp.json

@@ -3,7 +3,7 @@
     "harbor-hub": {
       "type": "stdio",
       "command": "bash",
-      "args": ["${CLAUDE_PLUGIN_ROOT:-.}/scripts/start-server.sh"]
+      "args": ["${CLAUDE_PLUGIN_ROOT}/scripts/start-server.sh"]
     }
   }
 }

harbor-mcp/README.md

@@ -44,9 +44,15 @@ You do not need a global harbor install: harbor ships inside the plugin's enviro
 uv sync
 ```
 
-The same [`.mcp.json`](.mcp.json) serves both cases: it runs [`scripts/start-server.sh`](scripts/start-server.sh) at `${CLAUDE_PLUGIN_ROOT:-.}`, which resolves to the installed plugin directory when loaded as a plugin and to this directory when Claude Code is started from here.
+Run the server directly:
 
-That wrapper exists for a reason worth knowing: naming `uv` directly as the command assumes it is on whatever PATH the MCP client spawns with, and it often is not. A Homebrew `uv` lives in `/opt/homebrew/bin`, which is missing from the minimal PATH some launch contexts provide, and the server then fails with an opaque JSON-RPC `-32000` and no explanation. The wrapper searches PATH plus the common install locations, resolves the plugin root from its own location, and prints an actionable message to stderr if `uv` genuinely is not installed.
+```bash
+./scripts/start-server.sh
+```
+
+[`.mcp.json`](.mcp.json) is the **plugin** config and only works when loaded as a plugin, because `${CLAUDE_PLUGIN_ROOT}` is substituted by the plugin loader. Do not add a `:-default` to it to make local discovery work, which is what broke it for three releases: the `:-default` form is handled by environment-variable expansion, which does not know `CLAUDE_PLUGIN_ROOT`, so the default silently won and the server was launched against whatever project the user happened to be in. It failed as an opaque JSON-RPC `-32000`, visible only in `~/Library/Caches/claude-cli-nodejs/<project>/mcp-logs-plugin-harbor-mcp-harbor-hub/`. Two tests in [tests/unit/test_plugin_config.py](tests/unit/test_plugin_config.py) now guard this.
+
+[`scripts/start-server.sh`](scripts/start-server.sh) resolves the plugin root from its own location, finds `uv` on PATH or in the common install directories, drops an inherited `VIRTUAL_ENV`, and writes diagnostics to stderr so stdout stays a clean JSON-RPC channel.
 
 ## Tools
 

harbor-mcp/tests/unit/test_plugin_config.py

@@ -0,0 +1,55 @@
+"""Guards on the shipped plugin config.
+
+These exist because a bad .mcp.json fails at MCP connect time with an opaque
+-32000 that no other test can see, and the first three attempts at this file all
+shipped broken.
+"""
+
+import json
+from pathlib import Path
+
+REPO = Path(__file__).resolve().parents[2]
+MCP_CONFIG = REPO / ".mcp.json"
+PLUGIN_MANIFEST = REPO / ".claude-plugin" / "plugin.json"
+
+
+def server_config() -> dict:
+    return json.loads(MCP_CONFIG.read_text())["mcpServers"]["harbor-hub"]
+
+
+def test_plugin_root_has_no_default_fallback():
+    """`${CLAUDE_PLUGIN_ROOT:-.}` silently expands to `.`, not the plugin root.
+
+    The `:-default` form is handled by env-var expansion, which does not know
+    CLAUDE_PLUGIN_ROOT, so the default always won and the server was launched
+    against the user's own project directory. Only the bare form is substituted
+    by the plugin loader.
+    """
+    for arg in server_config()["args"]:
+        assert ":-" not in arg, (
+            f"{arg!r} uses a :-default; CLAUDE_PLUGIN_ROOT must be bare or it "
+            "expands to the default and the server launches from the wrong "
+            "directory"
+        )
+
+
+def test_launcher_path_exists():
+    """The referenced script must actually ship, or bash exits before the server runs."""
+    args = server_config()["args"]
+    assert len(args) == 1, f"expected a single script argument, got {args}"
+    relative = args[0].replace("${CLAUDE_PLUGIN_ROOT}/", "")
+    script = REPO / relative
+    assert script.is_file(), f"{script} is referenced by .mcp.json but does not exist"
+    assert script.stat().st_mode & 0o111, f"{script} is not executable"
+
+
+def test_manifest_version_matches_nothing_stale():
+    """Version is the plugin cache key, so it must be a real semver triple.
+
+    A malformed version would land users in an unexpected cache directory.
+    """
+    version = json.loads(PLUGIN_MANIFEST.read_text())["version"]
+    parts = version.split(".")
+    assert len(parts) == 3 and all(p.isdigit() for p in parts), (
+        f"version {version!r} must be MAJOR.MINOR.PATCH"
+    )