PolicyEngine · PavelMakarchuk · Mar 18, 2026 · Mar 18, 2026
diff --git a/.claude-plugin/marketplace.json b/.claude-plugin/marketplace.json
@@ -25,6 +25,7 @@
         "./skills/documentation/policyengine-user-guide-skill",
         "./skills/domain-knowledge/policyengine-us-skill",
         "./skills/domain-knowledge/policyengine-uk-skill",
+        "./skills/domain-knowledge/policyengine-canada-skill",
         "./skills/documentation/policyengine-writing-skill"
       ]
     },
@@ -185,6 +186,7 @@
         "./skills/tools-and-apis/policyengine-microsimulation-skill",
         "./skills/domain-knowledge/policyengine-us-skill",
         "./skills/domain-knowledge/policyengine-uk-skill",
+        "./skills/domain-knowledge/policyengine-canada-skill",
         "./skills/domain-knowledge/policyengine-healthcare-skill",
         "./skills/analysis/policyengine-analysis-skill",
         "./skills/technical-patterns/python-skill",
@@ -311,6 +313,7 @@
       "skills": [
         "./skills/domain-knowledge/policyengine-us-skill",
         "./skills/domain-knowledge/policyengine-uk-skill",
+        "./skills/domain-knowledge/policyengine-canada-skill",
         "./skills/domain-knowledge/policyengine-healthcare-skill",
         "./skills/documentation/policyengine-user-guide-skill",
         "./skills/tools-and-apis/policyengine-microsimulation-skill",

diff --git a/changelog.d/canada-skill.added.md b/changelog.d/canada-skill.added.md
@@ -0,0 +1 @@
+Add Canada domain skill with household-only analysis (no microsimulation)
diff --git a/skills/domain-knowledge/policyengine-canada-skill/SKILL.md b/skills/domain-knowledge/policyengine-canada-skill/SKILL.md
@@ -0,0 +1,353 @@
+---
+name: policyengine-canada
+description: |
+  ALWAYS LOAD THIS SKILL FIRST before writing any PolicyEngine-Canada code.
+  Contains Canadian federal and provincial tax/benefit rules for household calculations.
+  IMPORTANT: PolicyEngine-Canada does NOT have representative population microdata.
+  Do NOT attempt microsimulation or population-level estimates for Canada.
+  Only provide household-level analysis (single-family impacts, eligibility, benefit amounts).
+  Triggers: "what would", "how much would a", "benefit be", "eligible for", "qualify for",
+  "single parent", "married couple", "family of", "household of", "if they earn",
+  "earning $", "making $", "calculate benefits", "calculate taxes", "benefit for a",
+  "what would I get", "what is the maximum", "what is the rate", "income limit",
+  "benefit amount", "maximum benefit", "compare provinces",
+  "CCB", "Canada Child Benefit", "GST credit", "HST credit", "GST/HST",
+  "OAS", "Old Age Security", "GIS", "Guaranteed Income Supplement",
+  "CWB", "Canada Workers Benefit", "EI", "Employment Insurance",
+  "CPP", "Canada Pension Plan", "RRSP", "TFSA",
+  "Ontario Child Benefit", "OCB", "Ontario Trillium Benefit", "OTB",
+  "BC Climate Action", "Alberta Child Benefit", "Quebec",
+  "CRA", "Canada Revenue Agency", "Canadian", "Canada",
+  "Ontario", "British Columbia", "Alberta", "Saskatchewan", "Manitoba",
+  "Nova Scotia", "New Brunswick", "PEI", "Newfoundland", "Yukon", "NWT", "Nunavut",
+  "provincial tax", "federal tax Canada".
+---
+
+# PolicyEngine-Canada
+
+> **IMPORTANT: Always use the current year (2026) in calculations, not 2024 or 2025.**
+
+## No Microsimulation for Canada
+
+**PolicyEngine-Canada does NOT have representative population microdata.** The only available
+dataset is a tiny template with 3 synthetic people. This means:
+
+- **Do NOT** use `Microsimulation()` from `policyengine_canada` for population-level estimates
+- **Do NOT** attempt to calculate aggregate costs, revenue impacts, or poverty rates for Canada
+- **Only provide household-level analysis**: calculate impacts for specific families using `Simulation`
+- If the user asks "what would X cost nationally" or "how many families would benefit", explain
+  that population-level estimates are not currently available for Canada and offer a household
+  example instead
+
+### What you CAN do
+
+- Calculate benefits/taxes for a specific household (income, province, family composition)
+- Compare baseline vs. reform for a single family
+- Show how benefits change across an income range
+- Compare provinces for a given household
+
+---
+
+PolicyEngine-Canada models the Canadian federal and provincial tax and benefit system.
+
+**What it models:**
+
+**Federal taxes:**
+- Federal income tax (5 brackets)
+- Canada Pension Plan (CPP/CPP2) contributions
+- Employment Insurance (EI) premiums
+
+**Federal benefits:**
+- Canada Child Benefit (CCB)
+- GST/HST Credit
+- Canada Workers Benefit (CWB)
+- Old Age Security (OAS)
+- Guaranteed Income Supplement (GIS)
+- Climate Action Incentive Payment (CAIP)
+
+**Provincial programs (varies by province):**
+- Provincial income tax (all provinces and territories)
+- Ontario Child Benefit (OCB)
+- Ontario Trillium Benefit (OTB)
+- BC Climate Action Tax Credit
+- Alberta Child and Family Benefit
+- Quebec-specific programs (QST, QPP, etc.)
+
+**See full list:** https://policyengine.org/ca/parameters
+
+---
+
+## Key Federal Programs — Rules Reference
+
+### Canada Child Benefit (CCB) — 2025–2026
+
+The CCB is a tax-free monthly payment to eligible families with children under 18.
+
+**Maximum amounts (July 2025 – June 2026):**
+- Under 6: **$7,997**/child/year ($666.41/month)
+- Ages 6–17: **$6,748**/child/year ($562.33/month)
+
+**Phase-out structure:**
+The CCB is reduced based on adjusted family net income (AFNI) using two thresholds.
+
+**Threshold 1: $37,487**
+| Number of children | Reduction rate (AFNI $37,487–$79,845) |
+|---|---|
+| 1 child | 7.0% |
+| 2 children | 13.5% |
+| 3 children | 19.0% |
+| 4+ children | 23.0% |
+
+**Threshold 2: $79,845**
+| Number of children | Reduction rate (AFNI above $79,845) |
+|---|---|
+| 1 child | 3.2% |
+| 2 children | 5.7% |
+| 3 children | 8.0% |
+| 4+ children | 9.5% |
+
+**Child Disability Benefit (CDB) supplement:**
+- Up to **$3,411**/year ($284.25/month) per child eligible for the Disability Tax Credit
+- Reduced at 3.2% of AFNI above $79,845 (1 child), 5.7% (2+ children)
+
+**CCB calculation formula:**
+```
+For each income range:
+  CCB = sum(max_amount per child) - reduction
+
+  If AFNI <= $37,487: no reduction
+  If $37,487 < AFNI <= $79,845:
+    reduction = rate_tier1 × (AFNI - $37,487)
+  If AFNI > $79,845:
+    reduction = rate_tier1 × ($79,845 - $37,487) + rate_tier2 × (AFNI - $79,845)
+```
+
+**Example calculation — 2 children (ages 3, 8), AFNI = $80,000:**
+```
+Max CCB = $7,997 (under 6) + $6,748 (6-17) = $14,745
+Tier 1 reduction = 13.5% × ($79,845 - $37,487) = 13.5% × $42,358 = $5,718
+Tier 2 reduction = 5.7% × ($80,000 - $79,845) = 5.7% × $155 = $9
+Total reduction = $5,727
+CCB = $14,745 - $5,727 = $9,018/year
+```
+
+### Federal Income Tax — 2026
+
+**Tax brackets:**
+| Taxable income | Rate |
+|---|---|
+| Up to $57,375 | 15% |
+| $57,375 – $114,750 | 20.5% |
+| $114,750 – $158,468 | 26% |
+| $158,468 – $220,000 | 29% |
+| Over $220,000 | 33% |
+
+**Basic personal amount (BPA):** $16,129 (2026, indexed)
+
+> Note: Bracket thresholds are indexed annually to inflation. Check CRA for exact 2026 values.
+
+### GST/HST Credit — 2025–2026
+
+Tax-free quarterly payment for low/modest-income individuals and families.
+
+**Maximum amounts (July 2025 – June 2026):**
+- Single: **$340**/year
+- Married/common-law: **$340** + **$179** for spouse = **$519**
+- Per child under 19: **$179**
+
+**Phase-out:**
+- Begins at family net income of **$44,530**
+- Reduction rate: 5% of income above threshold
+
+### Canada Workers Benefit (CWB) — 2026
+
+Refundable tax credit for low-income workers.
+
+**Single individuals:**
+- Maximum: ~**$1,590**
+- Phase-in: 27% of working income above $3,000
+- Phase-out: 15% of net income above ~$24,975
+
+**Families:**
+- Maximum: ~**$2,739**
+- Phase-in: 27% of working income above $3,000
+- Phase-out: 15% of family net income above ~$28,494
+
+**Disability supplement:**
+- Additional ~**$784** for CWB-eligible individuals with the Disability Tax Credit
+
+### Old Age Security (OAS) — 2026
+
+Monthly pension for seniors 65+.
+
+**Maximum amounts (Q1 2026):**
+- Ages 65–74: ~**$727.67**/month ($8,732/year)
+- Ages 75+: ~**$800.44**/month ($9,605/year)
+
+**OAS recovery tax (clawback):**
+- Threshold: ~**$90,997** net income
+- Rate: 15% of income above threshold
+- Full clawback at ~**$149,211** (65–74) or ~**$154,196** (75+)
+
+### Guaranteed Income Supplement (GIS) — 2026
+
+Monthly benefit for low-income OAS pensioners.
+
+**Maximum amounts (Q1 2026):**
+- Single: ~**$1,086.88**/month
+- Spouse receives OAS: ~**$654.23**/month each
+
+**Income test:**
+- Reduced by 50% (or 75% for partial amounts) of income above exempted amounts
+- Employment income exemption: first $5,000 fully exempt, next $10,000 at 50%
+
+---
+
+## Provincial Tax — Ontario (2026)
+
+**Ontario income tax brackets:**
+| Taxable income | Rate |
+|---|---|
+| Up to $52,886 | 5.05% |
+| $52,886 – $105,775 | 9.15% |
+| $105,775 – $150,000 | 11.16% |
+| $150,000 – $220,000 | 12.16% |
+| Over $220,000 | 13.16% |
+
+**Ontario surtax:**
+- 20% of basic provincial tax above $5,315
+- Plus 36% of basic provincial tax above $6,802
+
+### Ontario Child Benefit (OCB)
+
+- Maximum: **$1,726.92**/child/year ($143.91/month) for July 2025 – June 2026
+- Phase-out begins at family net income of **$24,045**
+- Reduction rate: 8% per child of income above threshold
+
+### Ontario Trillium Benefit (OTB)
+
+Combines three credits:
+1. **Ontario Energy and Property Tax Credit** — up to $1,248 (seniors $1,421)
+2. **Northern Ontario Energy Credit** — up to $180 (families $277)
+3. **Ontario Sales Tax Credit** — up to $360/adult + $360/child
+
+---
+
+## Provincial Tax — Other Provinces
+
+### British Columbia (2026)
+| Taxable income | Rate |
+|---|---|
+| Up to $47,937 | 5.06% |
+| $47,937 – $95,875 | 7.70% |
+| $95,875 – $110,076 | 10.50% |
+| $110,076 – $133,664 | 12.29% |
+| $133,664 – $181,232 | 14.70% |
+| Over $181,232 | 20.50% |
+
+### Alberta (2026)
+| Taxable income | Rate |
+|---|---|
+| Up to $148,269 | 10% |
+| $148,269 – $177,922 | 12% |
+| $177,922 – $237,230 | 13% |
+| $237,230 – $355,845 | 14% |
+| Over $355,845 | 15% |
+
+### Quebec (2026)
+| Taxable income | Rate |
+|---|---|
+| Up to $51,780 | 14% |
+| $51,780 – $103,545 | 19% |
+| $103,545 – $126,000 | 24% |
+| Over $126,000 | 25.75% |
+
+> Note: Quebec has its own tax system (Revenu Québec) with unique credits and deductions. QPP replaces CPP.
+
+---
+
+## CPP Contributions — 2026
+
+**CPP (first ceiling):**
+- Maximum pensionable earnings: ~**$71,300**
+- Basic exemption: $3,500
+- Employee rate: 5.95%
+- Maximum employee contribution: ~$4,034
+
+**CPP2 (second ceiling):**
+- Second ceiling: ~**$81,200**
+- Rate: 4% on earnings between first and second ceiling
+- Maximum CPP2 contribution: ~$396
+
+---
+
+## EI Premiums — 2026
+
+- Maximum insurable earnings: ~**$65,700**
+- Employee premium rate: 1.64%
+- Maximum employee premium: ~$1,077
+- Quebec rate: 1.32% (due to QPIP)
+
+---
+
+## Household Analysis Patterns
+
+### Answering "What would [reform] cost/mean for a family?"
+
+1. **Identify the family**: income, province, number/ages of children
+2. **Calculate baseline**: apply current rules to compute total benefits/taxes
+3. **Calculate reform**: apply modified rules
+4. **Report the difference**: reform minus baseline
+
+### Example: Doubling the CCB for an Ontario family
+
+**Family:** 2 parents, 2 children (ages 3, 8), AFNI $80,000, Ontario
+
+**Baseline CCB:**
+```
+Max = $7,997 + $6,748 = $14,745
+Reduction = 13.5% × ($79,845 - $37,487) + 5.7% × ($80,000 - $79,845)
+         = $5,718 + $9 = $5,727
+Baseline CCB = $14,745 - $5,727 = $9,018
+```
+
+**Doubled CCB:**
+```
+Max = $15,994 + $13,496 = $29,490
+Reduction = 13.5% × ($79,845 - $37,487) + 5.7% × ($80,000 - $79,845)
+         = $5,718 + $9 = $5,727
+Doubled CCB = $29,490 - $5,727 = $23,763
+```
+
+**Additional benefit = $23,763 - $9,018 = $14,745/year**
+
+> Key insight: When only the maximum amounts are doubled (not the phase-out rates), the additional benefit equals the original maximum for families whose benefits aren't fully phased out. The phase-out claws back the same dollar amount regardless of the benefit level.
+
+---
+
+## Common Pitfalls
+
+### 1. CCB Uses Adjusted Family Net Income (AFNI)
+AFNI is the combined net income (line 23600) of both spouses/partners. It is NOT individual income.
+
+### 2. Benefits Use Previous Year's Income
+CCB payments from July 2025 – June 2026 are based on **2024 tax year** income.
+
+### 3. Provincial Programs Stack on Federal
+Many provinces have their own child benefits on top of the federal CCB. Always check for provincial supplements.
+
+### 4. Quebec Is Different
+Quebec has its own pension plan (QPP), parental insurance (QPIP), and many unique credits. Don't assume federal rules apply.
+
+### 5. Indexation
+Most thresholds and amounts are indexed annually to CPI. Always verify the year-specific values.
+
+---
+
+## Additional Resources
+
+- **CRA Benefits Calculator:** https://www.canada.ca/en/revenue-agency/services/child-family-benefits/child-family-benefits-calculator.html
+- **PolicyEngine Canada:** https://policyengine.org/ca
+- **Variable Explorer:** https://policyengine.org/ca/variables
+- **Parameter Explorer:** https://policyengine.org/ca/parameters
+- **GitHub:** https://github.com/PolicyEngine/policyengine-canada
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		Add Canada domain skill with household-only analysis (no microsimulation)