Introspection¶

The __describe__ endpoint returns a RecordBatch describing all registered methods. It is called automatically by the Python client's describe() method:

from vgi_rpc import Client
client = Client(["./my-server"])
info = client.describe()

Response Contents¶

The describe response includes:

Method names
Method types (unary, producer, exchange)
Parameter schemas (field names, Arrow types, defaults)
Result schemas
Header schemas (for streaming methods with headers)
Server implementation metadata

Schema Version¶

The describe schema version is tracked by vgirpc.DescribeVersion (currently "2"). The response metadata also includes:

Metadata key	Value
`vgi_rpc.protocol_name`	Server implementation name (e.g. `"vgi-rpc-go"`)
`vgi_rpc.describe_version`	Schema version for the describe format

HTTP Access¶

Over HTTP, the describe endpoint is available at:

POST /vgi/__describe__

The request body should be an Arrow IPC stream with empty metadata (or the standard describe parameters).