feat(tools/postgres-list-views): add new postgres-list-views tool (#1709)

## Description

Adds a read-only PostgreSQL custom list_views tool, that returns the
details of views present in database. Each row includes: schema_name,
view_name, owner_name
Test Output:

<img width="2433" height="1274" alt="Screenshot 2025-10-19 at 3 59
31 PM"
src="https://github.com/user-attachments/assets/76e1e994-390a-4239-aba7-0d02253bbcc4"
/>
<img width="2533" height="1017" alt="Screenshot 2025-10-19 at 4 07
25 PM"
src="https://github.com/user-attachments/assets/537fbddd-d862-4044-a09b-cb9f180c21fa"
/>

## PR Checklist

> Thank you for opening a Pull Request! Before submitting your PR, there
are a
> few things you can do to make sure it goes smoothly:

- [x] Make sure you reviewed

[CONTRIBUTING.md](https://github.com/googleapis/genai-toolbox/blob/main/CONTRIBUTING.md)
- [x] Make sure to open an issue as a

[bug/issue](https://github.com/googleapis/genai-toolbox/issues/new/choose)
  before writing your code! That way we can discuss the change, evaluate
  designs, and agree on the general idea
- [x] Ensure the tests and linter pass
- [x] Code coverage does not decrease (if any source code was changed)
- [x] Appropriate docs were updated (if necessary)
- [x] Make sure to add `!` if this involve a breaking change

🛠️ Fixes #1738

Co-authored-by: Averi Kitsch <akitsch@google.com>

docs/en/reference/prebuilt-tools.md

@@ -43,6 +43,8 @@ details on how to connect your AI tools (IDEs) to databases via Toolbox and MCP.
     *   `list_replication_slots`: Lists replication slots in the database.
     *   `list_invalid_indexes`: Lists invalid indexes in the database.
     *   `get_query_plan`: Generate the execution plan of a statement.
+    *   `list_views`: Lists views in the database from pg_views with a default
+        limit of 50 rows. Returns schemaname, viewname and the ownername.
 
 ## AlloyDB Postgres Admin
 
@@ -210,6 +212,8 @@ details on how to connect your AI tools (IDEs) to databases via Toolbox and MCP.
     *   `list_replication_slots`: Lists replication slots in the database.
     *   `list_invalid_indexes`: Lists invalid indexes in the database.
     *   `get_query_plan`: Generate the execution plan of a statement.
+    *   `list_views`: Lists views in the database from pg_views with a default
+        limit of 50 rows. Returns schemaname, viewname and the ownername.
 
 ## Cloud SQL for PostgreSQL Observability
 
@@ -492,6 +496,8 @@ details on how to connect your AI tools (IDEs) to databases via Toolbox and MCP.
     *   `list_replication_slots`: Lists replication slots in the database.
     *   `list_invalid_indexes`: Lists invalid indexes in the database.
     *   `get_query_plan`: Generate the execution plan of a statement.
+    *   `list_views`: Lists views in the database from pg_views with a default
+        limit of 50 rows. Returns schemaname, viewname and the ownername.
 
 ## Google Cloud Serverless for Apache Spark
 

docs/en/resources/sources/alloydb-pg.md

@@ -45,6 +45,9 @@ cluster][alloydb-free-trial].
 - [`postgres-list-installed-extensions`](../tools/postgres/postgres-list-installed-extensions.md)
   List installed extensions in a PostgreSQL database.
 
+- [`postgres-list-views`](../tools/postgres/postgres-list-views.md)
+  List views in an AlloyDB for PostgreSQL database.
+
 ### Pre-built Configurations
 
 - [AlloyDB using MCP](https://googleapis.github.io/genai-toolbox/how-to/connect-ide/alloydb_pg_mcp/)

docs/en/resources/sources/cloud-sql-pg.md

@@ -41,6 +41,9 @@ to a database by following these instructions][csql-pg-quickstart].
 - [`postgres-list-installed-extensions`](../tools/postgres/postgres-list-installed-extensions.md)
   List installed extensions in a PostgreSQL database.
 
+- [`postgres-list-views`](../tools/postgres/postgres-list-views.md)
+  List views in a PostgreSQL database.
+
 ### Pre-built Configurations
 
 - [Cloud SQL for Postgres using

docs/en/resources/sources/postgres.md

@@ -35,6 +35,9 @@ reputation for reliability, feature robustness, and performance.
 - [`postgres-list-installed-extensions`](../tools/postgres/postgres-list-installed-extensions.md)
   List installed extensions in a PostgreSQL database.
 
+- [`postgres-list-views`](../tools/postgres/postgres-list-views.md)
+  List views in a PostgreSQL database.
+
 ### Pre-built Configurations
 
 - [PostgreSQL using MCP](https://googleapis.github.io/genai-toolbox/how-to/connect-ide/postgres_mcp/)

docs/en/resources/tools/postgres/postgres-list-views.md

@@ -0,0 +1,40 @@
+---
+title: "postgres-list-views"
+type: docs
+weight: 1
+description: >
+  The "postgres-list-views" tool lists views in a Postgres database, with a default limit of 50 rows.
+aliases:
+- /resources/tools/postgres-list-views
+---
+
+## About
+
+The `postgres-list-views` tool retrieves a list of top N (default 50) views from a Postgres database, excluding those in system schemas (`pg_catalog`, `information_schema`). It's compatible with any of the following sources:
+
+- [alloydb-postgres](../../sources/alloydb-pg.md)
+- [cloud-sql-postgres](../../sources/cloud-sql-pg.md)
+- [postgres](../../sources/postgres.md)
+
+`postgres-list-views` lists detailed view information (schemaname, viewname, ownername) as JSON for views in a database. The tool takes the following input parameters:
+
+- `viewname` (optional): A string pattern to filter view names. The search uses SQL 
+   LIKE operator to filter the views. Default: `""`
+- `limit` (optional): The maximum number of rows to return. Default: `50`.
+
+## Example
+
+```yaml
+tools:
+  list_views:
+    kind: postgres-list-views
+    source: cloudsql-pg-source
+```
+
+## Reference
+
+| **field**   | **type** | **required**  | **description**                                      |
+|-------------|:--------:|:-------------:|------------------------------------------------------|
+| kind        |  string  |     true      | Must be "postgres-list-views".                      |
+| source      |  string  |     true      | Name of the source the SQL should execute on.        |
+| description |  string  |     false     | Description of the tool that is passed to the agent. |