QPromiseRegistry

QPromiseRegistry and peek_context are the package exports that implement in-flight deduplication.

Import Paths

from pmll_memory_mcp import QPromiseRegistry, peek_context

Source files:

• mcp/pmll_memory_mcp/q_promise_bridge.py
• mcp/pmll_memory_mcp/peek.py

QPromiseRegistry

Constructor:

QPromiseRegistry() -> None

register

register(promise_id: str) -> None

Parameter	Type	Default	Description
promise_id	str	—	Unique identifier for an in-flight operation.

resolve

resolve(promise_id: str, payload: str) -> bool

Parameter	Type	Default	Description
promise_id	str	—	Promise to resolve.
payload	str	—	Final resolved value.

Returns True when the promise existed.

peek_promise

peek_promise(promise_id: str) -> tuple[bool, str \| None, str \| None]

Returns (found, status, payload).

__len__

__len__() -> int

__contains__

__contains__(promise_id: object) -> bool

peek_context

peek_context(
    key: str,
    session_id: str,
    store: PMMemoryStore,
    promise_registry: QPromiseRegistry,
) -> dict[str, Any]

Parameter	Type	Default	Description
key	str	—	Context key to inspect.
session_id	str	—	Session identifier used by the caller.
store	PMMemoryStore	—	Session-local KV store.
promise_registry	QPromiseRegistry	—	Shared registry of in-flight work.

Return shapes:

• {"hit": True, "value": str, "index": int}
• {"hit": True, "status": "pending", "promise_id": str}
• {"hit": False}

The implementation order matters: peek_context() checks the store before the registry. If you have already committed a value with store.set(), the function returns the cached payload even when an older promise record still exists.

Example

from pmll_memory_mcp import PMMemoryStore, QPromiseRegistry, peek_context

store = PMMemoryStore()
registry = QPromiseRegistry()
registry.register("session-1:fetch")

print(peek_context("session-1:fetch", "session-1", store, registry))
registry.resolve("session-1:fetch", "done")
store.set("session-1:fetch", "done")
print(peek_context("session-1:fetch", "session-1", store, registry))

Notes

• The registry does not remove resolved promises automatically.
• Promise IDs should be namespaced by the caller, usually with the session ID embedded into the key.