Generate timeline Skill

When to Use This Skill

Use this skill when you need to:

Calculate project duration using critical path method (CPM)
Identify critical path tasks (zero float tasks that drive project duration)
Perform PERT analysis (optimistic/most_likely/pessimistic time estimates)
Assess timeline risks (statutory deadline compliance, float analysis)
Calculate resource requirements (staff, consultants, budget by phase)
Optimize project schedule (identify bottlenecks, dependency chains)
Generate Gantt charts for visualization and communication

Critical Path Method (CPM) Fundamentals

What is Critical Path?

Critical path: Longest sequence of dependent tasks that determines minimum project duration.

Critical tasks: Tasks with zero total float (any delay directly extends project completion).

Total float: Amount of time a task can be delayed without extending project duration.

Critical path tasks: Total float = 0 days
Non-critical tasks: Total float > 0 days (schedule flexibility)

Free float: Amount of time a task can be delayed without delaying any successor.

Forward Pass & Backward Pass

Forward pass: Calculate earliest start/finish times

Start with day 0
Early start = max(predecessor early finishes)
Early finish = early start + duration

Backward pass: Calculate latest start/finish times

Start with project end date
Late finish = min(successor late starts)
Late start = late finish - duration

Float calculation:

Total float = late start - early start (or late finish - early finish)
Free float = min(successor early starts) - early finish

Example Calculation

Tasks:

A: Duration 10 days (no predecessors)
B: Duration 20 days (after A)
C: Duration 15 days (after A)
D: Duration 5 days (after B and C)

Forward pass:

A: ES=0, EF=10
B: ES=10, EF=30
C: ES=10, EF=25
D: ES=30 (max of B and C), EF=35

Backward pass:

D: LS=30, LF=35
B: LS=10, LF=30
C: LS=15, LF=30
A: LS=0, LF=10

Float:

A: 0 (critical)
B: 0 (critical)
C: 5 days (LS 15 - ES 10)
D: 0 (critical)

Critical path: A → B → D (35 days)

PERT Analysis

Three-Point Estimates

PERT uses three time estimates to account for uncertainty:

Optimistic (O): Best-case scenario (everything goes perfectly)
Most Likely (M): Realistic scenario (normal conditions)
Pessimistic (P): Worst-case scenario (significant problems)

PERT Formulas

Expected time (weighted average):

TE = (O + 4M + P) / 6

Standard deviation:

σ = (P - O) / 6

Variance:

σ² = ((P - O) / 6)²

Project variance (sum of critical path task variances):

Project σ² = Σ(critical path task variances)

Project standard deviation:

Project σ = √(Project σ²)

Confidence Intervals

90% confidence interval (Z = 1.645):

Lower bound = Expected duration - 1.645 × Project σ
Upper bound = Expected duration + 1.645 × Project σ

95% confidence interval (Z = 1.960):

Lower bound = Expected duration - 1.960 × Project σ
Upper bound = Expected duration + 1.960 × Project σ

Example PERT Calculation

Task: Prepare expropriation plan

Optimistic: 14 days
Most Likely: 21 days
Pessimistic: 35 days

Expected time:

TE = (14 + 4×21 + 35) / 6 = (14 + 84 + 35) / 6 = 133 / 6 = 22.2 days

Standard deviation:

σ = (35 - 14) / 6 = 21 / 6 = 3.5 days

Variance:

σ² = 3.5² = 12.25

Interpretation: Task will take approximately 22 days, with ±3.5 days variability.

Integration with OEA Statutory Deadlines

Statutory Deadline Constraints

3-Month Registration Deadline (OEA s.9(2)):

Expropriation plan must be registered within 90 days of approval
Deadline is absolute (approval expires if missed)
Critical path must complete plan registration by day 85 (5-day buffer)

Form 2 Service (Best Practice):

Serve Notice of Application 30 days before registration
Not statutory, but reduces procedural challenges

Form 7 Service (OEA s.11):

Serve Notice of Expropriation at least 30 days before possession
Statutory minimum (can give more time)

Deadline Risk Assessment

Buffer analysis:

Buffer = Statutory deadline - Task late finish

Risk levels:

CRITICAL: Buffer < 0 (task finishes AFTER deadline)
HIGH: Buffer 0-5 days (insufficient buffer)
MEDIUM: Buffer 5-10 days (below minimum buffer)
LOW: Buffer > 10 days (adequate buffer)

Example:

Statutory deadline: Day 90 (registration)
Task late finish: Day 91 (plan registration)
Buffer: 90 - 91 = -1 day (CRITICAL risk - misses deadline)

Calculator Usage

Input Format

JSON input structure:

{
  "project_name": "Transit Station Property Acquisition",
  "approval_date": "2025-03-15",
  "tasks": [
    {
      "id": "A",
      "name": "Obtain approval",
      "duration": 30,
      "optimistic": 20,
      "most_likely": 30,
      "pessimistic": 45,
      "resources": {
        "staff": 2,
        "consultants": {"legal": 1},
        "budget": 15000
      }
    }
  ],
  "dependencies": [
    ["A", "B"]
  ],
  "statutory_deadlines": {
    "G": 90
  },
  "buffer_days": 10
}

Command Line Usage

Basic calculation:

python project_timeline_calculator.py sample_1_simple_acquisition.json

Specify output location:

python project_timeline_calculator.py input.json -o Reports/timeline_analysis.md

JSON output format:

python project_timeline_calculator.py input.json -f json -o results.json

Verbose output:

python project_timeline_calculator.py input.json -v

Output Report

Markdown report includes:

Executive Summary: Project duration, critical path percentage, risk summary
Critical Path Analysis: Sequence of critical tasks with schedule
Statutory Deadlines: OEA milestone dates and compliance status
Risk Assessment: Timeline risks by severity (critical/high/medium/low)
Task Details Table: All tasks with early/late dates, float, criticality
Gantt Chart: Text-based visualization of timeline
Resource Requirements: Total and peak resource needs
Dependency Analysis: Complexity metrics and bottleneck identification

Resource Requirements Analysis

Resource Calculation

For each task, specify:

Staff: Number of staff required (concurrent)
Consultants: Number by type (legal, surveyor, appraiser, etc.)
Budget: Cost allocated to task

Calculator computes:

Total staff-days: Σ(staff × duration)
Total consultant-days: Σ(consultants × duration) by type
Total budget: Σ(task budgets)
Peak resources: Maximum concurrent staff/consultants at any point

Resource Leveling

Identify resource bottlenecks:

Tasks with peak resource requirements (> 5 concurrent staff)
Critical path tasks with high resource needs (no flexibility)
Resource conflicts (multiple tasks requiring same consultant)

Mitigation strategies:

Delay non-critical tasks (use available float)
Increase resources during peak periods
Outsource specialist work (appraisals, surveys)

Dependency Analysis

Dependency Complexity Metrics

Total dependencies: Number of predecessor-successor relationships

Average dependencies per task: Total dependencies ÷ Total tasks

Simple project: < 1.5 dependencies/task
Moderate complexity: 1.5 - 2.5 dependencies/task
High complexity: > 2.5 dependencies/task

Dependency density: Total dependencies ÷ (Total tasks)²

Measures interconnectedness
Higher density = more complex, rigid schedule

Bottleneck tasks: Tasks with 3+ dependencies (predecessors or successors)

High risk: Any delay cascades through project
Monitor closely, allocate extra resources

Dependency Types

Finish-to-Start (FS): Successor starts after predecessor finishes

Example: "Prepare plan" → "Review plan"
Most common dependency type

Start-to-Start (SS): Tasks start together

Example: "Negotiation" starts when "Appraisal" starts
Used for parallel work streams

Finish-to-Finish (FF): Tasks finish together

Example: "Legal review" finishes when "Plan preparation" finishes
Used for coordinated completions

Start-to-Finish (SF): Rare, successor finishes when predecessor starts

Uncommon in expropriation projects

Note: Current calculator supports Finish-to-Start only. For other types, model as multiple FS dependencies.

Risk Assessment

Timeline Risk Categories

1. Statutory Deadline Risk:

Task late finish exceeds statutory deadline
Severity: CRITICAL (approval expires)
Mitigation: Crash critical path, expedite reviews, obtain second approval

2. Critical Path No-Float Risk:

Critical path task with zero schedule flexibility
Severity: MEDIUM
Mitigation: Add buffer time, parallel work streams, increase resources

3. Long Duration Risk:

Task duration > 60 days (potential for unforeseen delays)
Severity: LOW
Mitigation: Break into sub-tasks, weekly monitoring

4. Dependency Bottleneck Risk:

Task with 3+ dependencies (delays cascade)
Severity: MEDIUM
Mitigation: Early coordination, dedicated resources

Risk Mitigation Strategies

Crashing the schedule (reduce critical path duration):

Add resources to critical path tasks
Work overtime / weekends
Outsource work to expedite
Fast-track (overlap dependent tasks if possible)

Fast-tracking:

Start successor before predecessor 100% complete
Risk: Rework if predecessor output changes
Example: Start plan review while plan preparation 80% complete

Buffering:

Add contingency time to critical path
Project buffer: 10-15% of critical path duration
Feeding buffers: Protect critical path from non-critical delays

Worked Example

Sample Input

Project: Transit station property acquisition (see samples/sample_1_simple_acquisition.json)

Key tasks:

A: Obtain approval (30 days)
B: Prepare plan (21 days) - after A
C: Plan review (7 days) - after B
D: Corrections (10 days) - after C
E: Solicitor approval (7 days) - after D
F: Registry scheduling (15 days) - after E
G: Plan registration (1 day) - after F
H: Appraisal (30 days) - after A, parallel to B-G
I: Prepare Form 2 (5 days) - after A
J: Serve Form 2 (1 day) - after I

Statutory deadline: Task G (registration) must complete by day 90.

Critical Path Analysis

Critical path: A → B → C → D → E → F → G

Project duration: 30 + 21 + 7 + 10 + 7 + 15 + 1 = 91 days

Problem: Critical path (91 days) exceeds statutory deadline (90 days) by 1 day!

Buffer: 90 - 91 = -1 day (CRITICAL risk)

PERT Analysis

Task B (Prepare plan):

Optimistic: 14 days
Most Likely: 21 days
Pessimistic: 35 days

Expected time: (14 + 4×21 + 35) / 6 = 22.2 days (vs. 21 deterministic)

Standard deviation: (35 - 14) / 6 = 3.5 days

Project with PERT estimates: ~92 days (expected)

90% confidence interval: 86 - 98 days
Probability of meeting 90-day deadline: ~30% (not acceptable)

Risk Mitigation

Option 1: Crash critical path

Reduce Task B (plan preparation) from 21 → 18 days (add surveyor)
Reduce Task C (plan review) from 7 → 5 days (priority review)
New duration: 88 days (2-day buffer)

Option 2: Fast-track

Start Task C (review) when Task B is 90% complete (overlap 2 days)
Start Task F (registry scheduling) during Task E (parallel booking)
New duration: 87 days (3-day buffer)

Option 3: Parallel work streams

Split plan preparation into multiple parcels
Register parcels as ready (rolling registration)
Risk: Complex coordination, higher legal costs

Recommended: Combination of Options 1 and 2 to achieve 85-day completion (5-day buffer).

Integration with Other Skills

Complementary skills:

expropriation-statutory-deadline-tracking:
- Operational deadline monitoring (weekly checks, escalation)
- This skill: Quantitative schedule calculation
expropriation-compensation-entitlement-analysis:
- Legal entitlement to compensation components
- This skill: Timeline for compensation calculation tasks
land-assembly-expert:
- Multi-property acquisition strategy
- This skill: Timeline for land assembly projects

Automated Workflow

Calculator follows PDF → JSON → Python → Report pattern:

Input: User creates JSON file with tasks, dependencies, deadlines
Validation: Schema validation ensures data integrity
Calculation: PERT/CPM analysis computes critical path
Risk Assessment: Identifies deadline compliance and timeline risks
Output: Markdown report with Gantt chart, JSON data export

No manual intervention required - fully automated from input to report.

Slash Command Integration

Argument hint: <project-milestones-json> [--output <report-path>]

Required tools: Read, Write, Bash

Canonical invocation (how the slash command passes user input):

python plugins/expropriation-law/skills/expropriation-timeline-expert/timeline_generator.py {{arg0}}

Usage examples:

# Generate timeline
/expropriation-timeline project_milestones.json

# Custom output path
/expropriation-timeline samples/transit_corridor_timeline.json --output $CLAUDE_PROJECT_DIR/Reports/timeline.md

Related commands: /briefing-note (include timeline in executive briefing), /board-memo (include timeline in board approval memo), /land-assembly (multi-parcel timeline with phasing)

Related agents: Stevi (compliance and deadline watchdog), Christi (legal procedures), Katy/Shadi (project planning)

Limitations

Current implementation:

Supports Finish-to-Start (FS) dependencies only
Assumes deterministic resource availability
Does not optimize resource allocation (requires manual leveling)
Weekends/holidays not modeled (calendar days only)

For advanced features:

Use project management software (Microsoft Project, Primavera P6)
Resource optimization algorithms
Monte Carlo simulation (10,000+ scenarios)
Earned value analysis (budget vs. actual tracking)

Agent Skills: Generate timeline

Install this agent skill to your local

Skill Files

When to Use This Skill

Critical Path Method (CPM) Fundamentals

What is Critical Path?

Forward Pass & Backward Pass

Example Calculation

PERT Analysis

Three-Point Estimates

PERT Formulas

Confidence Intervals

Example PERT Calculation

Integration with OEA Statutory Deadlines

Statutory Deadline Constraints

Deadline Risk Assessment

Calculator Usage

Input Format

Command Line Usage

Output Report

Resource Requirements Analysis

Resource Calculation

Resource Leveling

Dependency Analysis

Dependency Complexity Metrics

Dependency Types

Risk Assessment

Timeline Risk Categories

Risk Mitigation Strategies

Worked Example

Sample Input

Critical Path Analysis

PERT Analysis

Risk Mitigation

Integration with Other Skills

Automated Workflow

Slash Command Integration

Limitations