REQ-FUN-102

Activity dependency model with FS/SS/FF/SF and lag/lead

ID: REQ-FUN-102
Category: Functional Requirements
Status: approved
Priority: P0
Created: 2026-05-11T18:34:00.000Z
Approved: 2026-05-11T18:37:00.000Z
Updated: 2026-05-11T18:37:00.000Z

What

System SHALL model activity dependencies as directed edges with predecessor_id, successor_id, dependency_type (FS, SS, FF, SF), lag_days (signed integer; negative value represents lead).

Why

established project management guidelines Sequence Activities produces the project schedule network diagram. All four dependency types and lag/lead are foundational to realistic schedules.

How

Activity_dependency table FK-bound to activity on both ends; CHECK constraint disallows self-loop; bulk dependency declaration accepted as part of activity create payload; cycle detection runs server-side on every dependency insert (HTTP 409 with code dependency_cycle on detection).

Done when

All four types round-trip via REST and MCP; cycle insertion is rejected with documented error code; lag_days of -3 produces the expected computed start shift in the critical path output.

Out of scope

Hammock activities, soft-logic constraints, fractional-day lag.

established project management guidelines Mapping

Primary Knowledge Area: Schedule Management
Secondary KAs: Integration Management
Primary Process Group: Planning
established project management guidelines Deliverable: Schedule Management Plan, Schedule Baseline

Dependency modeling is the network-diagram primitive that established project management guidelines Sequence Activities produces.