## Description
---
This pull request introduces a new custom tool kind
`postgres-list-tables` that allows users to list tables within a
Postgres database.
### Example Configuration
```yaml
tools:
postgres_list_tables:
kind: postgres-list-tables
source: postgres-source
description: Use this tool to retrieve schema information for all or specified tables. Output format can be simple (only table names) or detailed.
```
### Example Request
```
curl -X POST http://127.0.0.1:5000/api/tool/postgres_list_tables/invoke \
-H "Content-Type: application/json" \
-d '{
"table_names": "users",
"output_format": "simple"
}'
```
## 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)
- [ ] Make sure to open an issue as a
[bug/issue](https://github.com/googleapis/langchain-google-alloydb-pg-python/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
---------
Co-authored-by: Averi Kitsch <akitsch@google.com>
