Web-Algebra

Instead of agents executing semantic workflows step-by-step through individual MCP tool calls, Web-Algebra enables agents to compile entire workflows into optimized JSON "bytecode" that executes atomically - enabling complex multi-operation compositions.

See WebAlgebra in action - translating natural language into RDF operations.

The system is built around theOperationabstract base class that provides:

- Registry System: Auto-discovery of operations fromsrc/web_algebra/operations/
- JSON DSL: Operations use@opkey withargsfor parameters, supporting nested operation calls
- RDFLib Type System: UsesURIRef,Literal,Graph, andResulttypes internally for proper RDF handling
- Execution Engine: Both standalone execution and MCP server integration
- Context System: ForEach operations set row context for inner operations to access viaValue
- URI Resolution: Proper semantic URI construction withResolveURIoperation

The operations cover read-write Linked Data, SPARQL queries, URI manipulation, and LinkedDataHub-specific resource creation. Non-exhaustive list:

- CONSTRUCT
- DESCRIBE
- SELECT
- Substitute
- Values
- SPARQLString

- ExtractClasses
- ExtractDatatypeProperties
- ExtractObjectProperties
- ExtractOntology

- ResolveURI
- EncodeForURI
- Concat
- Replace
- Str
- STRUUID
- URI

- Value
- Variable
- ForEach
- Filter
- Bindings
- Current
- Execute
- Merge

- ldh-CreateContainer
- ldh-CreateItem
- ldh-List
- ldh-AddFile
- ldh-AddGenericService
- ldh-AddResultSetChart
- ldh-AddSelect
- ldh-AddView
- ldh-AddObjectBlock
- ldh-AddXHTMLBlock
- ldh-RemoveBlock
- ldh-GeneratePortal
- ldh-GenerateClassContainers
- ldh-GenerateOntologyViews

Currently requires OpenAI API access.OPENAI_API_KEYenv value has to be set.

uv run python src/web_algebra/main.py --from-json ./examples/united-kingdom-cities.json

- Run LinkedDataHub v5
- Executesrc/web_algebra/main.py, it expects the path to your LDH's owner certificate and its password as arguments. For example:

uv run python src/web_algebra/main.py --from-json ./examples/united-kingdom-cities.json \ --cert_pem_path ../LinkedDataHub/ssl/owner/cert.pem \ --cert_password 

Here and throughout this guide, the client certificate/password arguments are only required for authentication with LinkedDataHub. You don't need them if you're not using LinkedDataHub with Web Algebra.

uv run uvicorn web_algebra.server:app --reload

or with LinkedDataHub certificate credentials (change the path and password to yours):

CERT_PEM_PATH="/Users/Martynas.Jusevicius/WebRoot/LinkedDataHub/ssl/owner/cert.pem" CERT_PASSWORD="" uv run uvicorn web_algebra.server:app --reload

http://localhost:6274/?MCP_PROXY_AUTH_TOKEN=b31e4b3d852b5a2445f45032c484e54e319bf16359585858cf88fe9a90816744