Construction Law: FIDIC, PSSCOC, SIA & Singapore SOP Act

FIDIC (Red/Yellow/Silver), PSSCOC, SIA, and Singapore SOP Act toolkit. Generate notices, claims, EOT applications, and obligations registers. Computes statutory deadlines against eGazette-verified holiday data. Use when (1) analysing contract clauses, risk allocation, or obligations; (2) preparing or reviewing claims (delay, disruption, prolongation, EOT, loss & expense); (3) comparing contract forms or advising on procurement strategy; (4) drafting or reviewing notices, correspondence, or contract documents; (5) building obligations registers or notice calendars; (6) discussing dispute resolution (DAB/DAAB, adjudication, arbitration, mediation, CAB); (7) Singapore-specific construction law (SOP Act, BCA, SIArb); (8) MDB procurement frameworks (ADB, World Bank). NOT for: non-construction commercial contracts, pure property/real-estate conveyancing, or insurance law.

⚠️ v2.11.0 users — action required if you computed non-SG deadlines. v2.11.0 shipped with bundled best-effort holiday data for AE, MY, and GB that was not verified against authoritative sources. If you ran the FIDIC Deadline Calculator against a non-SG seat using v2.11.0, re-check those deadlines against your jurisdiction’s official gazette. From v2.11.1 onward, only Singapore holidays are bundled (gazette-verified); other jurisdictions require --holidays-file with your own verified data. See the FIDIC Deadline Calculator section for details.

Analyze construction contracts, claims, notices, payment timelines, risk allocation, and dispute pathways across major standard forms, with strong international and Singapore-focused coverage.

Why install this?

• ✅ Avoid missed notice deadlines and time-bar mistakes
• ✅ Structure claims and EOT submissions faster
• ✅ Compare contract risk and obligations more consistently
• ✅ Prompts for the correct contract form and edition before analysis

Who this skill is for

This skill is built for:

• Construction lawyers
• In-house counsel
• Contract managers
• Commercial managers
• Quantity surveyors
• Claims consultants
• Project managers

What this skill does

Use this skill to:

• Identify the correct contract form and edition before analysis
• Review clauses for obligations, rights, risks, and time-bars
• Generate notice calendars and obligations registers
• Draft structured claim, EOT, variation, and payment templates
• Compare FIDIC forms across key topics
• Calculate Singapore SOP Act payment timelines
• Assess delay events, concurrency, EOT exposure, and LD risk
• Triage dispute resolution pathways

Supported forms and frameworks

• FIDIC Red Book 2017 (Construction)
• FIDIC Yellow Book 2017 (Plant & Design-Build)
• FIDIC Silver Book 2017 (EPC/Turnkey)
• PSSCOC (Construction Works)
• SIA Conditions (9th Edition)
• NEC (NEC3, NEC4) — notice calendar only
• JCT — pending
• Singapore SOP Act workflows

Why this skill matters

Construction outcomes often turn on details such as:

• the exact contract form and edition
• amended or bespoke clauses
• notice timing
• record quality
• causation
• quantification
• governing law

This skill helps you structure analysis quickly and consistently so you can spot risks early and avoid missing critical deadlines.

🇸🇬 Singapore matters — BCA circular awareness: BCA frequently updates SOP Act timelines, plan fees, CORENET-X procedures, BC1/structural codes, cost-sharing schemes, productivity grants, and buildability rules through circulars at https://www1.bca.gov.sg/resources/circulars/. If you maintain a local mirror (e.g. bca-circulars/ in your workspace, refreshed via a weekly heartbeat task), check it before relying on general knowledge. See references/singapore.md for details.

ℹ️ This skill does not fetch live BCA updates itself. If you maintain a local circulars mirror in your workspace, use it as an up-to-date reference alongside the skill.

CLI overview

text

Construction Law Skill — Unified CLI

Usage: construction_law.py <command> [options]

Available commands:

  intake       🏗️ Matter intake — guided issue triage (recommended starting point)
  wizard       🧙 Interactive guided prompts for tools
  notices      Generate notice/obligations calendar for a contract form
  claims       Generate claim notice/EOT/VO/disruption letters
  sop          Singapore SOP Act payment timeline calculator
  compare      Compare FIDIC contract forms side-by-side
  obligations  Generate party-by-party obligations register
  register     Generate Excel workbook of obligations + notices
  delay        Delay analysis & EOT entitlement calculator
  deadline     FIDIC deadline calculator — Singapore bundled; bring-your-own-holidays for other seats

Run any command with --help for its specific options, e.g.:
  python3 construction_law.py notices --help
  python3 construction_law.py claims --help

---

Start here

Recommended for all users: Matter Intake

The intake mode triages a construction issue and produces a professional report with clause buckets, deadline checks, amendment warnings, confidence labels, and recommended next steps.

bash

python3 scripts/construction_law.py intake
# or
python3 scripts/intake.py

Supports non-interactive mode for automation:

bash

python3 scripts/intake.py --file matter.json --output report.md --save-matter answers.json

Use non-interactive mode for repeatable internal workflows, templates, or batch matter intake.

Sample Matter Intake output

Example: delay / EOT issue under FIDIC Red 1999

text

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
 MATTER INTAKE — OUTPUT REPORT
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Contract:   FIDIC Red 1999
Governing:  Singapore
Party:      Contractor
Issue:      Delay / Extension of Time (EOT)
Objective:  Both EOT and additional payment

1. ISSUE SUMMARY
This appears to be a delay / EOT issue arising from late
access to site. The likely focus is notice compliance,
EOT entitlement, causation, and supporting records.

2. LIKELY CLAUSE BUCKETS
- Clause 2.1   Right of Access to Site
- Clause 8.4   Extension of Time
- Clause 20.1  Contractor's Claims

3. DEADLINE / TIME-BAR CHECK
Trigger:   Awareness of delaying event
Deadline:  28 days from awareness
Status:    ⚠️ Notice not confirmed
Risk:      Potential time-bar if late notice applies

4. AMENDMENT SENSITIVITY FLAGS
- Notice periods may be amended
- EOT wording may be narrowed
- Particular Conditions may override the standard form

5. RECOMMENDED NEXT STEPS
- confirm exact clause wording and edition
- verify whether notice was served in time
- gather programme and contemporaneous records
- prepare claim narrative and supporting documents

6. CONFIDENCE LABELS
Deadline calculation:      High confidence
Clause identification:     High confidence
Entitlement position:      Needs review

This is a workflow and analysis aid only. It is not legal advice.

🎯 For strategic claim planning, see the companion skill construction-claim-strategy on ClawHub (v1.5.0). It covers the 7-Dimension strategy framework, argument ranking, delay analysis methods (SCL Protocol, TIA, Windows Analysis), concurrent delay strategy, disruption claims, quantum calculation examples (Eichleay/Hudson/Emden/Measured Mile), ADR strategy (adjudication vs arbitration), notice compliance, expert engagement, risk assessment, pacing delays, legal precedents, and 22 printable reference documents — all BEFORE you select clauses or start drafting.

Interactive Wizard

For tool-specific tasks (notices, claims, SOP calculator, etc.), use the wizard:

bash

python3 scripts/construction_law.py wizard
# or
python3 scripts/wizard.py

For power users: Unified CLI

bash

python3 scripts/construction_law.py --list
python3 scripts/construction_law.py notices --form fidic-red
python3 scripts/construction_law.py notices --form fidic-silver
python3 scripts/construction_law.py claims --form fidic-red --type disruption-claim
python3 scripts/construction_law.py claims --form fidic-yellow --type eot-application
python3 scripts/construction_law.py claims --form fidic-silver --type notice-of-claim
python3 scripts/construction_law.py sop --claim-date 2026-05-15
python3 scripts/construction_law.py compare --forms red,yellow,silver --topic claims
python3 scripts/construction_law.py obligations --form fidic-silver --party both
python3 scripts/construction_law.py register --form fidic-red --type both --output reg.xlsx
python3 scripts/construction_law.py register --form fidic-silver --type both --output silver.xlsx
python3 scripts/construction_law.py delay --baseline-start 2026-05-01 --baseline-end 2026-12-31
python3 scripts/construction_law.py deadline --seat SG --trigger 2026-05-15 --period 28 --mode exclude_ph
python3 scripts/construction_law.py deadline --seat AE --trigger 2026-03-18 --period 28 --mode exclude_ph --holidays-file ae_holidays.json

💡 All three FIDIC colours supported: fidic-red, fidic-yellow, fidic-silver. Also: psscoc, sia.

Critical rule: always confirm the contract edition first

Before any clause analysis, confirm:

• contract form
• edition/year
• governing law
• amendments or particular conditions
• whether bespoke terms override the standard form

Do not assume the latest edition applies.

Common editions still in use

• PSSCOC: 2017, 2020
• PSSCOC D&B: 2014, 2020
• FIDIC: 1999, 2017
• SIA: 9th Ed, 11th Ed
• NEC: NEC3, NEC4

Core workflows

1. Clause analysis

For any clause question, this skill helps you:

• identify the relevant clause
• explain the obligation, entitlement, or risk
• flag notice periods and time-bars
• cross-reference related clauses
• highlight where amendments may change the default position

2. Claims and EOT analysis

For delay, disruption, prolongation, and related claims, use this structure:

1. Entitlement
2. Causation
3. Notice compliance
4. Substantiation
5. Quantification

3. Notice calendars

Build notice calendars that capture:

• clause reference
• trigger event
• notice period
• recipient
• consequence of non-compliance

4. Risk allocation review

Assess whether risk is allocated to the party best able to:

1. identify it
2. control it
3. mitigate it
4. absorb it

5. Delay and LD exposure

Review:

• delay event chronology
• criticality
• concurrency
• potential EOT entitlement
• potential liquidated damages exposure

Included tools

Interactive Wizard

Guided prompts for common tasks.

bash

python3 scripts/wizard.py

Notice Calendar Generator

Generate notice and obligations calendars.

bash

python3 scripts/notice_calendar.py --form fidic-red --format md
python3 scripts/notice_calendar.py --form fidic-yellow --format md
python3 scripts/notice_calendar.py --form fidic-silver --format md
python3 scripts/notice_calendar.py --form psscoc --format csv --output notices.csv

Claims Template Generator

Generate structured templates for claim notices and related submissions.

bash

python3 scripts/claims_template.py --list
python3 scripts/claims_template.py --form fidic-red --type notice-of-claim --output notice.md
python3 scripts/claims_template.py --form fidic-yellow --type eot-application --output eot_yellow.md
python3 scripts/claims_template.py --form fidic-silver --type notice-of-claim --output notice_silver.md
python3 scripts/claims_template.py --form psscoc --type eot-application --output eot.md

Obligations Register Generator

Create obligations registers by party and category.

bash

python3 scripts/obligations_register.py --form fidic-red --party both --format md
python3 scripts/obligations_register.py --form fidic-yellow --party contractor --format md
python3 scripts/obligations_register.py --form fidic-silver --party both --format md
python3 scripts/obligations_register.py --form psscoc --party contractor --format csv --output obligations.csv

SOP Act Payment Timeline Calculator

Calculate statutory payment deadlines from a Singapore payment claim date.

bash

python3 scripts/sop_calculator.py --claim-date 2026-06-30
python3 scripts/sop_calculator.py --claim-date 2026-06-30 --response-period 14 --format csv --output timeline.csv

FIDIC Contract Comparator

Compare FIDIC forms side by side.

bash

python3 scripts/fidic_comparator.py --forms red,yellow,silver --topic risk
python3 scripts/fidic_comparator.py --forms red,yellow,silver --topic all --format csv --output comparison.csv

Topics: overview, risk, claims, disputes, payment, termination, all

FIDIC Deadline Calculator (Seat-Aware)

Compute contractual deadlines based on the seat country's public holidays.

The FIDIC Deadline Calculator supports Singapore out of the box, with holiday data verified against the eGazette. Singapore data covers gazetted years (currently 2025–2026); the 2027 entry is provisional until MOM gazettes it (expected late 2026). For projects with a seat in any other jurisdiction, you must supply your own holiday list — the tool will not ship pre-loaded holiday data for non-Singapore seats. This is deliberate: holiday calendars vary by sub-jurisdiction (Malaysian state, UK constituent country, individual emirate), shift by moon-sighting, and are gazetted by your own government's authoritative source. Use that source, not ours.

Supports three day-counting modes:

• calendar — calendar-day counting; use where the relevant clause defines or operates on calendar days
• exclude_ph — calendar days excluding public holidays of the seat country
• working — excludes weekends AND public holidays (for contracts defining "working day")

bash

python3 scripts/fidic_deadline.py --list-seats
python3 scripts/fidic_deadline.py --seat SG --trigger 2026-05-15 --period 28
python3 scripts/fidic_deadline.py --seat SG --trigger 2026-05-15 --period 28 --mode exclude_ph
python3 scripts/fidic_deadline.py --seat AE --trigger 2026-03-18 --period 28 --mode exclude_ph --holidays-file ae_holidays.json
python3 scripts/fidic_deadline.py --seat MY --trigger 2026-02-15 --period 28 --mode working --holidays-file my_holidays.json

Bundled seat: SG (Singapore — gazette-verified). For any other jurisdiction, supply --holidays-file. See docs/holiday-file-format.md for the JSON schema and a worked example.

💡 Which mode to use? Check your contract's definition of "day". FIDIC 2017 standard = calendar days. If Particular Conditions amend this to exclude public holidays, use exclude_ph. If the contract uses "working days", use working.

Delay Analysis Calculator

Assess delay events, concurrency, EOT exposure, and LD risk.

bash

python3 scripts/delay_calculator.py --baseline-start 2026-05-11 --baseline-end 2030-05-10 \
  --add "Late access|2026-06-01|2026-06-30|employer|critical" \
  --add "Weather|2026-07-15|2026-07-25|neutral|critical"

Excel Register Generator

Export notice calendars and obligations registers to .xlsx.

bash

python3 scripts/excel_register.py --form fidic-red --type both --output contract_admin.xlsx --commencement 2026-05-11
python3 scripts/excel_register.py --form fidic-yellow --type both --output yellow_admin.xlsx
python3 scripts/excel_register.py --form fidic-silver --type both --output silver_admin.xlsx
python3 scripts/excel_register.py --form psscoc --type obligations --output obligations.xlsx

Requires: openpyxl (pip3 install openpyxl)

Example outputs

Notice calendar — concrete sample

text

Clause:    FIDIC 20.2.1
Trigger:   Event giving rise to claim
Deadline:  28 days from awareness
Recipient: Engineer
Risk:      Late notice may prejudice entitlement (time-bar)

Notice calendar — fields

• Clause reference
• Trigger event
• Notice deadline
• Recipient
• Time-bar consequence

Claims template

• Background
• Contract basis
• Event chronology
• Causation
• Notice compliance
• Relief sought
• Reservation of rights
• Supporting documents

Obligations register

• Clause
• Obligation
• Responsible party
• Timing
• Priority
• Status
• Notes

Best use cases

• preliminary clause review
• contract administration checklists
• claim structure and document preparation
• notice and deadline tracking
• form comparison
• SOP timeline calculation
• delay event triage

Important limitations

This skill is a workflow and analysis aid. It is not a substitute for legal advice.

Use caution where:

• the contract is heavily amended
• bespoke EPC or project-specific drafting applies
• governing law may materially change the outcome
• local statutory regimes override standard form assumptions
• adjudication, arbitration, or court submissions require final review

Always verify:

• the contract edition
• amendments and particular conditions
• governing law
• notice requirements
• jurisdiction-specific treatment of concurrency, good faith, prevention, and time-bars

Key principles

• Read the contract first
• Standard form positions mean little if amended
• Time-bars can be fatal
• Notice compliance should be checked before merits
• Concurrency treatment differs by jurisdiction
• Good faith is jurisdiction-specific
• Prevention issues may affect LD exposure
• Fitness for purpose and reasonable skill and care must be distinguished carefully

Reference files

• references/fidic.md
• references/singapore.md
• references/claims.md
• references/disputes.md
• references/procurement.md

Live knowledge sources (Singapore)

For up-to-date Singapore regulatory context, consult the BCA circulars page — the authoritative source for changes to SOP Act timelines, plan fees, CORENET-X, BC1/structural codes, cost-sharing schemes, productivity grants, and buildability requirements:

• Source: https://www1.bca.gov.sg/resources/circulars/
• Recommended setup: Maintain a local PDF mirror (e.g. bca-circulars/ in your workspace) refreshed weekly via a heartbeat or cron task. Track seen titles in a seen.json index to detect new circulars.

When advising on Singapore matters touching SOP Act timelines, plan fees, CORENET-X, BC1/structural codes, cost-sharing schemes, productivity grants, or buildability requirements, check the latest circulars first before relying on general knowledge — BCA updates can change deadlines, rates, and procedural requirements.

If your local mirror looks stale (>2 weeks old), trigger a fresh fetch.

🔒 Security and safety

All Python scripts in this skill are designed as safe, local template and register generators.

• ✅ No network access — no API calls, no HTTP requests
• ✅ No subprocess execution — no shell commands, no external programs
• ✅ No dynamic code loading — sibling scripts are imported as plain Python modules (no importlib, no exec, no eval)
• ✅ No telemetry from skill code — the bundled scripts do not collect or transmit data. (Note: your LLM provider’s normal data handling still applies.)
• ✅ No filesystem traversal — only writes to the user-specified --output path
• ✅ Read-only static reference data — contract clauses bundled with the skill
• ✅ ClawScan: Benign
• ✅ Static analysis: Benign
• ℹ️ VirusTotal status is shown on the listing page

Safe to install and use. 🛡️

Files written

Scripts write files only when you pass explicit output flags. If no output flag is provided, all output goes to stdout.

Script	Flag	What is written	Format
Any script	--output FILE	Generated report/template/calendar	UTF-8 (Markdown, CSV, or plain text)
excel_register.py	--output FILE.xlsx	Obligations/notices workbook	Excel (.xlsx, requires openpyxl)
claims_template.py	--output FILE.docx	Claim letter	Word (.docx, requires python-docx)
sop_calculator.py	--output FILE	SOP payment timeline	UTF-8 Markdown or CSV
fidic_deadline.py	--output FILE	Deadline calculation	UTF-8 text or Markdown

No files are created, modified, or read beyond the explicit input flags (--file, --holidays-file, --events-csv).

Dependencies

Core scripts use only the Python standard library. Optional features require:

Package	Required For	Install
openpyxl	Excel register output	pip3 install openpyxl
python-docx	Word document export	pip3 install python-docx

Declared in pyproject.toml as optional extras:

bash

pip3 install .[excel]    # Excel only
pip3 install .[all]      # Excel + Word
pip3 install .[test]     # pytest + hypothesis

Testing

The skill includes a multi-layer test suite (73 tests):

Layer 1 — Golden file (test_sop_golden.py): 8 hand-computed scenarios frozen in tests/data/golden_timelines.csv. Covers CNY cluster, Vesak/Hari Raya Haji, Christmas/New Year cross-year, National Day in-lieu, baseline, claim-on-PH, 14-day response, and s.17(2) +7 extension.

Layer 2 — Property-based (test_sop_properties.py): Hypothesis tests over 2025–2027 date range. Properties: deadline never on PH, strictly monotonic, round-trip sop_days_between, adding a holiday can only push later, result ≥ N calendar days.

Layer 3 — Boundary (test_sop_boundary.py): End-of-month, end-of-year, s.17(2) extension (verified as SOP days with PH skipping), claim on PH, consecutive holidays (3+ non-SOP days), out-of-range year (fails loud), Silver Book fitness-for-purpose assertion.

Register tests (test_registers.py): All forms produce valid MD/CSV, Silver Book has no Engineer, entry structure validation.

bash

cd skills/construction-law
pip3 install .[test]
python3 -m pytest tests/ -v
# or without pytest:
python3 -m unittest discover tests

Changelog

v2.11.5 (May 2026)

• MUST-FIX: _check_year_coverage now called from all public functions (is_sop_day, add_sop_days, sop_days_between) — previously only called from calc_timeline. Dates in uncovered years (e.g. 2028) now raise ValueError instead of silently treating all days as working days. Year-crossing within add_sop_days also checked.
• Docs: is_sop_day docstring clarifies: returns True for Saturdays/Sundays (they count as SOP days); raises ValueError for uncovered years (does not silently return False); ad-hoc holidays (e.g. Polling Day) require manual addition
• Docs: add_sop_days(start, 0) semantics documented (returns start unchanged; caller responsible for whether start is a working day)
• Docs: Ad-hoc holiday warning added to timeline output
• Docs: Error message now uses actual config path (_HOLIDAY_JSON.name) instead of hardcoded string
• Tests: 73 → 85. New: TestSaturdayDeadline (deadline on Saturday stays), TestInLieuCollision (synthetic collision sets exercise while-loop), TestOutOfRangeYear expanded (4 new: add_sop_days, is_sop_day, sop_days_between, year-crossing), golden row 9 (Saturday deadline + Labour Day PH skip)
• Tests: Property test date bounds tightened (MAX_DATE_FOR_ADD = 2027-10-01) to avoid crossing into uncovered 2028

v2.11.4 (May 2026)

• Security: Sanitised test docstrings and comments — removed function-call patterns that static analysis scanners match against English text

v2.11.3 (May 2026)

• Security: Replaced string-grep forbidden-imports check with ast.parse tree-walking — properly catches compile(...), exec(...), eval(...) regardless of whitespace or indirection; no longer false-positives on comments, docstrings, or strings containing those words

v2.11.2 (May 2026)

• Title: Updated to "Construction Law: FIDIC, PSSCOC, SIA & Singapore SOP Act"
• Advisory: Added v2.11.0 user advisory banner for non-SG deadline re-check
• Docs: Added CLI overview (--help output) to SKILL.md so users can evaluate commands without installing
• Docs: Tightened "No telemetry" statement to distinguish skill code from LLM provider data handling
• Docs: Added "Files written" section documenting exactly what each script writes and when
• Docs: SKILL.md changelog backfilled with v2.10.0–v2.11.1 entries (CHANGELOG.md remained the source of truth; SKILL.md was out of sync)
• Security: Added test_security.py — scans all 13 scripts for forbidden imports (subprocess, socket, requests, urllib.request, http.client, importlib, pickle, marshal, os.system, exec, eval, compile), enforcing the no-network/no-subprocess/no-dynamic-code claim at test time
• Docs: Recommend python3 -m unittest (stdlib) alongside pytest

v2.11.1 (May 2026)

• Scope correction: Removed bundled best-effort holiday data for AE, MY, GB — shipping unverified holiday data in a legal-deadline tool was the wrong call
• FIDIC Deadline Calculator now ships with Singapore holidays only (gazette-verified). Other jurisdictions: supply your own verified holiday data via --holidays-file
• Added docs/holiday-file-format.md with JSON schema, worked example, and source guidance
• Reduced golden deadline tests to Singapore-only; retained generic property tests

v2.11.0 (May 2026)

• New: FIDIC Deadline Calculator (fidic_deadline.py) — computes contractual deadlines in three modes: calendar (calendar-day counting), exclude_ph (excludes public holidays only), and working (excludes weekends + public holidays)
• Singapore calendar bundled and maintained — verified against eGazette / MOM source data
• Important: Holiday data covers Singapore only. For all other jurisdictions, users must supply their own gazette-verified holiday file via --holidays-file. The tool will prompt clearly if a non-SG seat is used without one.

v2.10.1 (May 2026)

• Reconciled CHANGELOG v2.8.1/v2.9.1 duplication
• Recategorized out-of-range ValueError as legal accuracy change
• Added per-year eGazette URL, MOM gazette cite, and holiday names to data/sg_holidays.json
• Added moon sighting notes for Hari Raya Puasa / Hari Raya Haji dates

v2.10.0 (May 2026)

• 3-layer test suite (57+ tests): golden-file, Hypothesis property-based, and boundary tests for SOP calculator; register tests for all forms
• Out-of-range year protection: Calculator now raises ValueError with a clear message when claim date's year has no holiday data (no silent wrong answers)
• pyproject.toml with optional extras ([excel], [word], [all], [test])
• data/sg_holidays.json as single source of truth with per-year provenance
• Disclaimer injection on all generated templates (visible text + HTML comment)
• Deprecated: --add pipe-delimited flag; replaced with --add-event (structured) and --events-csv (batch)
• Added: CHANGELOG.md with categorized convention

v2.9.0 (May 2026)

• FIDIC Silver Book (EPC/Turnkey) 2017 added as a fully-supported form. All 7 claim templates now have fidic-silver versions (notice-of-claim, eot-application, variation-claim, interim-claim, disruption-claim, loss-and-expense, final-account). Templates are tailored to EPC/Turnkey context: no Engineer (Employer administers directly via Employer's Representative), narrower EOT grounds under Sub-Clause 8.5, Contractor's broader risk assumption, lump sum pricing, fitness for purpose obligations, and design responsibility under Sub-Clause 5.
• fidic-silver obligations register added — 33 contractor obligations (including EPC-specific design, fitness for purpose, higher physical conditions threshold) and 11 employer obligations.
• fidic-silver notice calendar added — 12 key notices (claims, design, variations, disputes, payment) with Silver Book-specific recipients (Employer, not Engineer).
• Excel register now produces fidic-silver sheets for both obligations and notices.
• Full support matrix is now 35 combos (7 claim types × 5 forms: fidic-red, fidic-yellow, fidic-silver, psscoc, sia). NEC4 and JCT remain pending.
• Updated cross-references to companion skill construction-claim-strategy v1.5.0.

v2.8.1 (May 2026) — SOP holiday correctness fix

• Sunday → Monday in-lieu rule now applied automatically. Under the Holidays Act 1998 s.4(2), when a public holiday falls on a Sunday the following Monday is a public holiday in lieu. The previous bundled holiday list missed four such Mondays (1 Jun 2026 — Vesak in-lieu; 10 Aug 2026 — National Day in-lieu; 9 Nov 2026 — Deepavali in-lieu; 8 Feb 2027 — CNY Day 2 in-lieu). The SOP day arithmetic now derives in-lieu Mondays from the gazetted Sunday holidays automatically, so future gazette updates won't drift.
• This affects any SOP timeline whose computed window crosses a Sunday public holiday — deadlines could be off by one day under v2.8.0 and earlier. Re-run any SOP timelines you generated previously if the period crossed those dates.

v2.8.0 (May 2026)

• FIDIC Yellow Book 2017 added as a fully-supported form. All 7 claim templates now have fidic-yellow versions (notice-of-claim, eot-application, variation-claim, interim-claim, disruption-claim, loss-and-expense, final-account). Templates are tailored to Plant & Design-Build context: design responsibility (Cl. 5), Employer's Requirements (Cl. 1.9), milestone-based payment (Schedule of Payments), Tests after Completion (Cl. 12), and the 8.5 EOT grounds.
• fidic-yellow obligations register added — 33 contractor obligations (including design-specific clauses 5.1–5.8) and 12 employer obligations.
• Excel register now produces fidic-yellow obligations sheets in addition to notices.
• All new templates are edition-tagged in the HTML comment header and visible body.
• Full support matrix is now 28 combos (7 claim types × 4 forms: fidic-red, fidic-yellow, psscoc, sia). NEC4 and JCT remain pending.

v2.7.0 (May 2026)

• 6 new claim templates filling the PSSCOC + SIA gap: eot-application, variation-claim, and interim-claim now have full PSSCOC (7th Ed., 2014 rev. 2020) and SIA (9th Ed., 2010 rep. 2016) versions.
• All new templates are edition-tagged in an HTML comment header and in the visible body, so users know exactly which standard form edition the clauses correspond to.
• Interim-claim templates explicitly dual-purpose as SOP Act s.10 payment claims with the s.10(3) requirements ticked off.
• Full support matrix is now 21 combos (7 claim types × 3 forms).

v2.6.0 (May 2026)

• SOP calculator now holiday-aware. Periods are computed in SOP days (excluding Singapore public holidays per SOP Act s.2 read with the Holidays Act 1998). Previously used calendar-day arithmetic which silently produced wrong dates around holiday clusters.
• SOP timeline conceptual fix. Removed misleading min/max determination and payment-due rows; replaced with single statutory deadlines and an explicit s.17(2) +7-day extension note.
• Argparse no longer crashes on claims_template.py for fidic-yellow, nec4, or jct — unsupported forms are now rejected at parse time with a pointer to --list. Unsupported (form, type) combos within registered forms also fail with a helpful message.
• Excel register no longer writes half-empty workbooks. Pre-flight coverage check refuses combos like --form fidic-yellow --type obligations and prints what is supported.
• Version sprawl resolved. New scripts/version.py is the single source of truth; intake.py / wizard.py / delay_calculator.py / sop_calculator.py footers all aligned to v2.6.