Delegation and Retrieval Seams

These are optional adapter seams. They do not add a durable worker service, a vector database, or new Core wire contracts.

Delegation

A subagent manager owns local child runs:

• Modes: isolated starts with only the request; fork carries the parent message history.
• States: queued, running, completed, failed, canceled.
• Operations: launch, check, wait, optional mid-flight update, and cancel.
• Cancellation is local. It is not proof that remote work stopped.
• A terminal state is final for the local task; it is not an exactly-once or durable execution guarantee.

The Go reference is pkg/agent/delegation. Python provides praxo.delegation.SubagentManager with an async runner seam; TypeScript provides src/delegation.ts SubagentManager; Java provides agent.delegation.SubagentManager; Rust provides delegation::SubagentManager; C# provides Praxo.Core.Delegation.SubagentManager; R provides a synchronous subagent_run seam without an asynchronous manager; Ruby provides Delegation::SubagentManager; PHP provides a synchronous SubagentManager::run seam; Elixir provides Praxo.SubagentManager; Lua, C, C++, Fortran, Haskell, OCaml, Swift, Dart, Perl, D, Delphi/Free Pascal, Objective-C, Nim, V, Zig, Julia, MATLAB/Octave, Erlang, and COBOL provide synchronous seams; PowerShell wraps the C# manager. Other implementations do not have an in-tree delegation manager yet.

Retrieval

A retriever seam maps a query and limit to documents:

• Document: id, content, optional metadata, optional score.
• Retriever: retrieve query/limit and return documents.
• A function adapter is sufficient for local or caller-owned retrieval.

The Go reference is pkg/retriever. Python provides praxo.retriever with Document, Retriever, and FuncRetriever; TypeScript provides src/retriever.ts with the same shapes; Java provides retriever.Document and retriever.Retriever; Rust provides retriever::Document and Retriever; C# provides Praxo.Core.Retriever.Document and Retriever; R provides document and retriever_retrieve; Ruby provides Document and FuncRetriever; PHP provides Document, Retriever, and FuncRetriever; Elixir provides Praxo.Document and Praxo.FuncRetriever; Lua provides document and retriever_retrieve; C provides PxDocument and PxRetriever; C++ provides Document and Retriever; Fortran provides document and retriever; Haskell provides Praxo.Retriever.Document and Retriever; OCaml provides document and retrieve_documents; Swift provides Document, FuncRetriever, and retrieveDocuments; Dart provides Document, FuncRetriever, and retrieveDocuments; Perl provides document, func_retriever, and retrieve_documents; D provides Document, Retriever, FuncRetriever, and retrieveDocuments; Delphi provides TPraxoDocument, TPraxoRetriever, and PraxoRetrieveDocuments; Objective-C provides PXDocument, PXRetriever, and PXRetrieveDocuments; Nim provides Document, Retriever, FuncRetriever, and retrieveDocuments; V provides Document, Retriever, FuncRetriever, and retrieve_documents; Zig provides retriever.Document, retriever.Retriever, and retriever.retrieveDocuments; Julia provides Document, FuncRetriever, and retrieve_documents; MATLAB and GNU Octave provide shared praxo.document and praxo.retrieve_documents; Erlang provides praxo_retriever:document, func_retriever, and retrieve/3; COBOL provides praxo-retriever over a caller-supplied callback. Other implementations do not have an in-tree retriever yet.

Retrieval does not define an embedding model, vector store, ranking service, or search-quality claim. Memory stores and context compaction remain separate Core surfaces.

Baseline Status

The canonical per-language list is the adapter status and retriever tables. Current evidence is deterministic fixture or fake-runner coverage, not live worker or search systems.

Testing

Delegation tests cover launch, completion, failure, cancel, optional update, unknown tasks, and validation. Retrieval tests cover the document shape, query/limit forwarding, and the function seam.