feat: capacity-aware scheduling (#8) — real focus factors drive every forecast

Turns the single-serial-worker scheduler into a capacity-aware, multi-lane one.
Configured team members become lanes; an issue runs on its assignee's lane (or the
earliest-free lane), its duration scaled by that lane's throughput
(focusFactor × allocation). Every forecast — Focus cone, Runway, milestone
drill-in — is now capacity-aware.

core (@commitea/core):
- capacity/capacity-v0: CapacityMember + capacityPerWorkday + parseCapacityConfig
  (clamps, drops invalid; degrades to []).
- scheduler/scheduler-capacity-v0: scheduleWithCapacity reuses the v0 topo order +
  critical path, re-lays work across lanes (layoutOnLanes, resolveLanes, makespan).
  Empty workers → the single serial plan verbatim.
- forecast() gains options.workers: each MC trial lays sampled durations across the
  lanes and takes the makespan; serial path unchanged. SchedulableIssue gains
  assignee; ScheduledItem gains worker.
- 11 new tests (parse/clamp, parallelism halves makespan, speed scaling, assignee
  routing, cross-lane deps, forecast makespan shrinks with lanes).

app:
- pm-state capacity/members.json read (readCapacity + pmstate:capacity bridge);
  useCapacity hook → workers; forecastBacklog/runwayView/milestoneView pass workers.
- Runway Capacity card shows the real config (person · focus · alloc · pd/day).

Config lives in pm-state (D4); seeded christian(0.8)/stephen(0.6×0.5). Degrades to
the fixture/serial when absent.

Verified: 128 core tests green, desktop typecheck clean, 14 fixture e2e green. Live:
the capacity card is real, and the P2 forecast shifts 32d→37d — honest, since real
focus factors (<1) replace the v0 focus-1.0 assumption.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/core/src/capacity/capacity-v0.test.ts

@@ -0,0 +1,88 @@
+import { describe, expect, it } from 'vitest'
+
+import { type DependencyEdge, type SchedulableIssue } from '../scheduler/scheduler-v0.js'
+import { makespan, scheduleWithCapacity, type Worker } from '../scheduler/scheduler-capacity-v0.js'
+import { capacityPerWorkday, parseCapacityConfig } from './capacity-v0.js'
+
+describe('capacity model', () => {
+  it('capacityPerWorkday = focusFactor × allocation', () => {
+    expect(capacityPerWorkday({ person: 'a', focusFactor: 0.8, allocation: 0.5 })).toBeCloseTo(0.4)
+  })
+
+  it('parses + clamps config, drops invalid members', () => {
+    const members = parseCapacityConfig({
+      members: [
+        { person: 'christian', focusFactor: 0.8, allocation: 1 },
+        { person: 'ak', focusFactor: 1.5, allocation: -1 }, // clamps to 1 / 0 → zero capacity → dropped
+        { focusFactor: 0.8 }, // no person → dropped
+      ],
+    })
+    expect(members).toEqual([{ person: 'christian', focusFactor: 0.8, allocation: 1 }])
+  })
+
+  it('returns [] for a non-array/absent members field', () => {
+    expect(parseCapacityConfig({})).toEqual([])
+    expect(parseCapacityConfig({ members: 'nope' })).toEqual([])
+  })
+})
+
+function issue(number: number, over: Partial<SchedulableIssue> = {}): SchedulableIssue {
+  return { number, title: `#${number}`, labels: [], estimateDays: 4, priority: 2, ...over }
+}
+
+describe('scheduleWithCapacity', () => {
+  it('with no workers, falls back to the single serial plan', () => {
+    const issues = [issue(1), issue(2)]
+    const plan = scheduleWithCapacity(issues, [], [])
+    expect(makespan(plan)).toBe(8) // 4 + 4 serial
+  })
+
+  it('parallelizes independent work across lanes (makespan shrinks)', () => {
+    const issues = [issue(1), issue(2), issue(3), issue(4)] // 4×4d = 16d serial
+    const one: Worker[] = [{ person: 'a', speed: 1 }]
+    const two: Worker[] = [
+      { person: 'a', speed: 1 },
+      { person: 'b', speed: 1 },
+    ]
+    expect(makespan(scheduleWithCapacity(issues, [], one))).toBe(16)
+    expect(makespan(scheduleWithCapacity(issues, [], two))).toBe(8) // two lanes → half
+  })
+
+  it('scales duration by a lane speed (slower lane takes longer)', () => {
+    const plan = scheduleWithCapacity([issue(1, { estimateDays: 4 })], [], [{ person: 'a', speed: 0.5 }])
+    expect(plan.items[0].durationDays).toBe(8) // 4 / 0.5
+    expect(plan.items[0].worker).toBe('a')
+  })
+
+  it('routes an issue to its assignee lane', () => {
+    const issues = [issue(1, { assignee: 'ak' }), issue(2, { assignee: 'sm' })]
+    const workers: Worker[] = [
+      { person: 'ak', speed: 1 },
+      { person: 'sm', speed: 1 },
+    ]
+    const plan = scheduleWithCapacity(issues, [], workers)
+    const byN = Object.fromEntries(plan.items.map((i) => [i.number, i]))
+    expect(byN[1].worker).toBe('ak')
+    expect(byN[2].worker).toBe('sm')
+    // both start at 0 (different lanes) → parallel
+    expect(byN[1].startDay).toBe(0)
+    expect(byN[2].startDay).toBe(0)
+  })
+
+  it('adds a lane for an assignee not in the config (mean speed)', () => {
+    const plan = scheduleWithCapacity([issue(1, { assignee: 'newbie' })], [], [{ person: 'a', speed: 0.5 }])
+    expect(plan.items[0].worker).toBe('newbie')
+    expect(plan.items[0].durationDays).toBe(8) // mean speed 0.5 → 4/0.5
+  })
+
+  it('respects dependencies across lanes (a blocker finishes before its dependent starts)', () => {
+    const edges: DependencyEdge[] = [{ issue: 2, dependsOn: 1 }]
+    const workers: Worker[] = [
+      { person: 'a', speed: 1 },
+      { person: 'b', speed: 1 },
+    ]
+    const plan = scheduleWithCapacity([issue(1), issue(2)], edges, workers)
+    const byN = Object.fromEntries(plan.items.map((i) => [i.number, i]))
+    expect(byN[2].startDay).toBeGreaterThanOrEqual(byN[1].endDay) // #2 waits for #1 even on another lane
+  })
+})

packages/core/src/capacity/capacity-v0.ts

@@ -0,0 +1,49 @@
+/**
+ * Capacity model (#8). A member's throughput is `focusFactor × allocation` =
+ * ideal person-days of project work delivered per calendar working day. The
+ * scheduler treats each member as a lane whose task durations are scaled by that
+ * rate (a 0.5-capacity person takes twice as long on an est/2d task). Config
+ * lives in the pm-state repo (`capacity/members.yaml/json`, D4); estimates are
+ * in ideal person-days (pm-state.md).
+ */
+
+export interface CapacityMember {
+  /** gitea login. */
+  person: string
+  /** Productive fraction of a working day (0..1). */
+  focusFactor: number
+  /** Fraction of that allocated to this project (0..1). */
+  allocation: number
+}
+
+/** Ideal person-days delivered per calendar working day. */
+export function capacityPerWorkday(m: CapacityMember): number {
+  return m.focusFactor * m.allocation
+}
+
+function clamp01(n: unknown, fallback: number): number {
+  return typeof n === 'number' && Number.isFinite(n) ? Math.min(1, Math.max(0, n)) : fallback
+}
+
+/**
+ * Validate a raw capacity config (`{ members: [...] }`) into members. Unknown
+ * shapes degrade to `[]` (→ the scheduler falls back to a single worker), never
+ * throw. focusFactor/allocation clamp to [0,1]; a member without a person is dropped.
+ */
+export function parseCapacityConfig(raw: unknown): CapacityMember[] {
+  const list = (raw as { members?: unknown })?.members
+  if (!Array.isArray(list)) return []
+  const out: CapacityMember[] = []
+  for (const m of list) {
+    const r = (m ?? {}) as Record<string, unknown>
+    const person = typeof r.person === 'string' ? r.person.trim() : ''
+    if (!person) continue
+    const member: CapacityMember = {
+      person,
+      focusFactor: clamp01(r.focusFactor, 0.8),
+      allocation: clamp01(r.allocation, 1),
+    }
+    if (capacityPerWorkday(member) > 0) out.push(member)
+  }
+  return out
+}

packages/core/src/forecast/forecast-v0.test.ts

@@ -120,4 +120,20 @@ describe('forecast', () => {
     expect(fitted.coldStart).toBe(false)
     expect(fitted.p50Day).toBeLessThan(priors.p50Day)
   })
+
+  it('capacity lanes parallelize the sim — the makespan shrinks with more workers', () => {
+    const independent = [issue(1), issue(2), issue(3), issue(4)] // no deps → fully parallelizable
+    const serial = forecast(independent, [], { trials: 2000, seed: 7 })
+    const twoLanes = forecast(independent, [], {
+      trials: 2000,
+      seed: 7,
+      workers: [
+        { person: 'a', speed: 1 },
+        { person: 'b', speed: 1 },
+      ],
+    })
+    // two equal lanes ≈ half the serial landing (independent work)
+    expect(twoLanes.p80Day).toBeLessThan(serial.p80Day)
+    expect(twoLanes.p80Day).toBeLessThan(serial.p80Day * 0.7)
+  })
 })

packages/core/src/forecast/forecast-v0.ts

@@ -18,6 +18,7 @@ import {
   schedule,
   type SchedulableIssue,
 } from '../scheduler/scheduler-v0.js'
+import { type LaneInputs, layoutOnLanes, resolveLanes, type Worker } from '../scheduler/scheduler-capacity-v0.js'
 
 export interface LognormalPrior {
   /** Median log-ratio: sampled median duration = estimate * e^mu. */
@@ -76,6 +77,12 @@ export interface ForecastOptions {
    * the sim; otherwise the code-resident cold-start priors do.
    */
   model?: DurationModel
+  /**
+   * Capacity lanes. When provided, each trial lays sampled durations across the
+   * lanes (parallel) instead of a single serial worker — the makespan shrinks
+   * toward the critical path. Empty/absent → single serial worker.
+   */
+  workers?: Worker[]
 }
 
 /** Resolve the lognormal params for an estimate, preferring a fitted model. */
@@ -158,15 +165,32 @@ export function forecast(
   const priors = order.map((it) => durationParams(it.durationDays, options.model))
   const rng = mulberry32(seed)
 
-  // endByRank[k][t] = working day the (k+1)-th scheduled issue completes on trial t.
+  // Capacity lanes, when configured — the per-trial layout goes parallel.
+  const laneInputs: LaneInputs = {
+    order: order.map((it) => it.number),
+    blockedBy: new Map(order.map((it) => [it.number, it.blockedBy])),
+    assignee: new Map(issues.map((i) => [i.number, i.assignee ?? null])),
+  }
+  const lanes =
+    options.workers && options.workers.length ? resolveLanes(options.workers, [...laneInputs.assignee.values()]) : null
+
+  // endByRank[k][t] = working day the (k+1)-th issue *to finish* completes on trial t.
   const endByRank: number[][] = Array.from({ length: n }, () => new Array<number>(trials))
   for (let t = 0; t < trials; t++) {
-    let cursor = 0
-    for (let k = 0; k < n; k++) {
-      const p = priors[k]
-      const sampled = order[k].durationDays * Math.exp(p.mu + p.sigma * standardNormal(rng))
-      cursor += sampled
-      endByRank[k][t] = cursor
+    const sampled = order.map((it, k) => it.durationDays * Math.exp(priors[k].mu + priors[k].sigma * standardNormal(rng)))
+    if (lanes) {
+      // parallel: lay the sampled durations across lanes, then sort finish days
+      const byNumber = new Map(order.map((it, k) => [it.number, sampled[k]]))
+      const { finishAt } = layoutOnLanes(laneInputs, lanes, (num) => byNumber.get(num)!)
+      const finishes = order.map((it) => finishAt.get(it.number)!).sort((a, b) => a - b)
+      for (let k = 0; k < n; k++) endByRank[k][t] = finishes[k]
+    } else {
+      // single serial worker: cumulative sum (already sorted ascending)
+      let cursor = 0
+      for (let k = 0; k < n; k++) {
+        cursor += sampled[k]
+        endByRank[k][t] = cursor
+      }
     }
   }
 

packages/core/src/index.ts

@@ -49,6 +49,12 @@ export type {
   SchedulePlan,
 } from './scheduler/scheduler-v0.js'
 
+export { makespan, scheduleWithCapacity } from './scheduler/scheduler-capacity-v0.js'
+export type { Worker } from './scheduler/scheduler-capacity-v0.js'
+
+export { capacityPerWorkday, parseCapacityConfig } from './capacity/capacity-v0.js'
+export type { CapacityMember } from './capacity/capacity-v0.js'
+
 export {
   COLD_START_PRIORS,
   durationParams,

packages/core/src/scheduler/scheduler-capacity-v0.ts

@@ -0,0 +1,119 @@
+/**
+ * Capacity-aware scheduler (#8). Reuses the single-worker scheduler's topological
+ * order + critical-path marking, then re-lays the work across lanes: an issue
+ * runs on its assignee's lane (or the earliest-free lane when unassigned), its
+ * duration scaled by that lane's speed (ideal person-days/workday). Makespan
+ * shrinks toward the critical path as lanes are added. Deterministic; falls back
+ * to the single serial worker when no capacity is configured. The lane layout is
+ * factored so the Monte Carlo forecast reuses it per trial with sampled durations.
+ */
+
+import {
+  type DependencyEdge,
+  schedule,
+  type SchedulableIssue,
+  type SchedulePlan,
+} from './scheduler-v0.js'
+
+/** A scheduling lane: a person and their throughput (ideal person-days / workday). */
+export interface Worker {
+  person: string
+  speed: number
+}
+
+/** The topological order + per-issue relations the layout needs (from the base plan). */
+export interface LaneInputs {
+  order: number[]
+  blockedBy: Map<number, number[]>
+  assignee: Map<number, string | null>
+}
+
+/** Ensure a lane exists for every assignee; unconfigured assignees get the mean speed. */
+export function resolveLanes(workers: Worker[], assignees: (string | null)[]): Worker[] {
+  const lanes = [...workers]
+  const known = new Set(lanes.map((w) => w.person))
+  const meanSpeed = lanes.length ? lanes.reduce((s, w) => s + w.speed, 0) / lanes.length : 1
+  for (const a of assignees) {
+    if (a && !known.has(a)) {
+      lanes.push({ person: a, speed: meanSpeed })
+      known.add(a)
+    }
+  }
+  return lanes
+}
+
+function pickWorker(lanes: Worker[], freeAt: Map<string, number>, assignee: string | null | undefined): Worker {
+  if (assignee) {
+    const own = lanes.find((w) => w.person === assignee)
+    if (own) return own
+  }
+  let best = lanes[0]
+  for (const w of lanes) if (freeAt.get(w.person)! < freeAt.get(best.person)!) best = w
+  return best
+}
+
+/**
+ * Lay a topologically-ordered set out across lanes. `duration(n)` supplies each
+ * issue's duration for this layout (estimate, or a sampled value in a MC trial).
+ * Returns each issue's finish day + the lane it ran on. Order guarantees a
+ * dependency is always laid out before its dependents.
+ */
+export function layoutOnLanes(
+  inputs: LaneInputs,
+  lanes: Worker[],
+  duration: (n: number) => number,
+): { finishAt: Map<number, number>; startAt: Map<number, number>; laneOf: Map<number, string> } {
+  const freeAt = new Map(lanes.map((w) => [w.person, 0]))
+  const finishAt = new Map<number, number>()
+  const startAt = new Map<number, number>()
+  const laneOf = new Map<number, string>()
+  for (const n of inputs.order) {
+    const worker = pickWorker(lanes, freeAt, inputs.assignee.get(n))
+    const blockers = inputs.blockedBy.get(n) ?? []
+    const depFinish = blockers.length ? Math.max(...blockers.map((d) => finishAt.get(d) ?? 0)) : 0
+    const start = Math.max(freeAt.get(worker.person)!, depFinish)
+    const end = start + duration(n) / worker.speed
+    startAt.set(n, start)
+    finishAt.set(n, end)
+    laneOf.set(n, worker.person)
+    freeAt.set(worker.person, end)
+  }
+  return { finishAt, startAt, laneOf }
+}
+
+/**
+ * Capacity-aware plan. An empty `workers` means no capacity is configured → the
+ * single-worker plan verbatim.
+ */
+export function scheduleWithCapacity(
+  issues: SchedulableIssue[],
+  edges: DependencyEdge[],
+  workers: Worker[],
+): SchedulePlan {
+  if (workers.length === 0) return schedule(issues, edges)
+  const base = schedule(issues, edges)
+  if (base.cycle || base.items.length === 0) return base
+
+  const inputs: LaneInputs = {
+    order: base.items.map((it) => it.number),
+    blockedBy: new Map(base.items.map((it) => [it.number, it.blockedBy])),
+    assignee: new Map(issues.map((i) => [i.number, i.assignee ?? null])),
+  }
+  const lanes = resolveLanes(workers, [...inputs.assignee.values()])
+  const durationOf = new Map(base.items.map((it) => [it.number, it.durationDays]))
+  const { finishAt, startAt, laneOf } = layoutOnLanes(inputs, lanes, (n) => durationOf.get(n)!)
+
+  const items = base.items.map((it) => ({
+    ...it,
+    startDay: startAt.get(it.number)!,
+    endDay: finishAt.get(it.number)!,
+    durationDays: finishAt.get(it.number)! - startAt.get(it.number)!,
+    worker: laneOf.get(it.number),
+  }))
+  return { items, cycle: null }
+}
+
+/** Makespan (last finish) of a plan — the project's landing day. */
+export function makespan(plan: SchedulePlan): number {
+  return plan.items.reduce((m, it) => Math.max(m, it.endDay), 0)
+}

packages/core/src/scheduler/scheduler-v0.ts

@@ -21,6 +21,8 @@ export interface SchedulableIssue {
   estimateDays: number | null
   /** 1 (most urgent) … 4; null when unset. */
   priority: number | null
+  /** gitea assignee login, for capacity-aware lane routing; optional. */
+  assignee?: string | null
 }
 
 export interface DependencyEdge {
@@ -45,6 +47,8 @@ export interface ScheduledItem {
   /** On a longest-duration dependency chain. */
   critical: boolean
   rationale: string
+  /** Lane it's scheduled on, when capacity-aware; absent for the single-worker plan. */
+  worker?: string
 }
 
 export interface SchedulePlan {