fixing bugs in MCP server

.gitignore

@@ -8,3 +8,4 @@ erl_crash.dump
 *.beam
 /config/*.secret.exs
 .elixir_ls/
+.idea

guided/config/test.exs

@@ -5,15 +5,32 @@ config :bcrypt_elixir, :log_rounds, 1
 
 # Configure your database
 #
-# The MIX_TEST_PARTITION environment variable can be used
-# to provide built-in test partitioning in CI environment.
-# Run `mix help test` for more information.
+# The Dockerized Postgres instance already has the AGE extension installed.
+# Reuse that database by default so graph queries keep working in tests.
+db_username =
+  System.get_env("TEST_DATABASE_USERNAME") || System.get_env("DATABASE_USERNAME") || "postgres"
+
+db_password =
+  System.get_env("TEST_DATABASE_PASSWORD") || System.get_env("DATABASE_PASSWORD") || "guided"
+
+db_hostname =
+  System.get_env("TEST_DATABASE_HOSTNAME") || System.get_env("DATABASE_HOSTNAME") || "localhost"
+
+db_port = System.get_env("TEST_DATABASE_PORT") || System.get_env("DATABASE_PORT") || "5455"
+db_name = System.get_env("TEST_DATABASE_NAME") || System.get_env("DATABASE_NAME") || "guided"
+
+db_name =
+  case System.get_env("MIX_TEST_PARTITION") do
+    nil -> db_name
+    partition -> "#{db_name}#{partition}"
+  end
+
 config :guided, Guided.Repo,
-  username: "postgres",
-  password: "guided",
-  hostname: "localhost",
-  port: 5455,
-  database: "guided_test#{System.get_env("MIX_TEST_PARTITION")}",
+  username: db_username,
+  password: db_password,
+  hostname: db_hostname,
+  port: String.to_integer(db_port),
+  database: db_name,
   pool: Ecto.Adapters.SQL.Sandbox,
   pool_size: System.schedulers_online() * 2
 

guided/lib/guided/graph.ex

@@ -34,12 +34,15 @@ defmodule Guided.Graph do
       {:ok, %Postgrex.Result{rows: [...]}}
   """
   def cypher(cypher_query, params \\ []) do
-    # Load the AGE extension (must be separate query)
-    with {:ok, _} <- query(Repo, "LOAD 'age'", [], []),
-         {:ok, _} <- query(Repo, "SET search_path = ag_catalog, \"$user\", public", [], []) do
+    # Run all commands in a transaction to ensure they use the same connection
+    Repo.transaction(fn ->
+      # Load the AGE extension and set search path
+      {:ok, _} = query(Repo, "LOAD 'age'", [], [])
+      {:ok, _} = query(Repo, "SET search_path = ag_catalog, \"$user\", public", [], [])
+
       # Build the Cypher query using AGE's cypher function
       # Convert agtype to text which Postgrex can handle
-      if params == [] do
+      result = if params == [] do
         sql_query = """
         SELECT ag_catalog.agtype_to_text(result) as result
         FROM ag_catalog.cypher('#{@graph_name}', $$#{cypher_query}$$) as (result ag_catalog.agtype)
@@ -55,9 +58,11 @@ defmodule Guided.Graph do
         query(Repo, sql_query, [@graph_name, cypher_query, params_json], [])
       end
 
-    else
-      {:error, error} -> {:error, error}
-    end
+      case result do
+        {:ok, data} -> data
+        {:error, error} -> Repo.rollback(error)
+      end
+    end)
   end
 
   @doc """