diff --git a/CHANGELOG.md b/CHANGELOG.md
index 70cff84..d302aba 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,42 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.4.0] - 2026-02-16
+
+Rules consolidation — 47 rules reduced to 17 focused rules, GitHub Copilot agent added, new governance and maintenance categories.
+
+### Added
+- [AGENT]: GitHub Copilot CLI — agent config, `.github/copilot-instructions.md`, 2 rules (COPILOT:S:0001, COPILOT:C:0001)
+- [CORE]: Governance category — cross-agent-compatibility (CORE:G:0001, moved from structure)
+- [CORE]: Maintenance category — valid-internal-references (CORE:M:0001), valid-glob-patterns-in-frontmatter (CORE:M:0002)
+- [RUNTIME]: Agent exclude patterns — `excludes` list in agent config.yml with wildcard support (`CLAUDE:*`)
+- [RUNTIME]: Agent-scoped rule discovery — `--agent` flag filters to agent's own rules plus core
+- [SOURCES]: 5 Copilot sources added to docs/sources.yml (copilot-cli-best-practices, copilot-coding-agent-best-practices, copilot-custom-instructions, awesome-copilot-meta-instructions, spec-writing-for-agents)
+
+### Changed
+- **BREAKING — Rules consolidation**: 47 rules → 17. Most rules moved to [reporails/recommended](https://github.com/reporails/recommended) or consolidated into broader rules
+- **BREAKING — Coordinate renumbering**: All coordinates reassigned from fresh sequence
+- [CORE:S]: 12 → 3 rules — root-instruction-file-presence (S:0001), monorepo-nested-instruction-files (S:0002), structured-markdown-format (S:0003)
+- [CORE:C]: 18 → 5 rules — include-project-context (C:0001), verification-build-commands (C:0002), project-architecture-documentation (C:0003), avoid-generic-placeholder-content (C:0004), boundary-constraints (C:0005)
+- [CLAUDE]: 10 → 3 rules — rules-directory-for-modular-instructions (S:0001), path-scoped-rules (S:0002), import-syntax-for-modular-content (C:0001)
+- [CODEX]: 7 → 1 rule — combined-instruction-size-limit (S:0001)
+- [REGISTRY]: Coordinate map rewritten for new rule set; tombstones cleared (fresh coordinate space — backfill planned for 0.5.0)
+- [DOCS]: CONTRIBUTING.md updated for multi-agent workflows (Claude Code, Codex, Copilot CLI)
+- [DOCS]: rule-template.md — improved pass/fail example formatting with fenced code blocks
+- [BACKBONE]: Added copilot agent entry (config, no skills directory)
+
+### Removed
+- [CORE:S]: 9 rules consolidated or moved to recommended (S:0002–S:0009, S:0011, S:0012)
+- [CORE:C]: 13 rules consolidated or moved to recommended (C:0004–C:0007, C:0009–C:0012, C:0015–C:0017, C:0019, C:0022–C:0025)
+- [CLAUDE]: 7 rules consolidated or moved to recommended (S:0001, S:0002, S:0004, S:0005, S:0008–S:0012)
+- [CODEX]: 6 rules consolidated or moved to recommended (S:0001–S:0007)
+
+### Metrics
+- Rules: 17 (11 core + 3 Claude + 1 Codex + 2 Copilot)
+- Schemas: 8 (rule, capability, levels, agent, package, project, sources, user)
+- Sources: 15 weighted sources
+- Agents: 3 (Claude, Codex, Copilot)
+
 ## [0.3.0] - 2026-02-10
 
 ### Added
diff --git a/CLAUDE.md b/CLAUDE.md
index 7ccfe8c..3d74d2f 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -59,8 +59,8 @@ docker compose -f runtime/docker-compose.yml run test --verbose
 
 Key paths:
 - @registry/ — Capabilities, levels, coordinate map, tombstones
-- @core/ — Core rules (12 structure, 18 content)
-- @agents/ — Agent-specific config and rules (10 Claude, 7 Codex)
+- @core/ — Core rules (3 structure, 5 content, 1 governance, 2 maintenance)
+- @agents/ — Agent-specific config and rules (3 Claude, 1 Codex, 2 Copilot)
 - @schemas/ — Machine-readable contracts (8 schemas)
 - @docs/ — Contributor guides and source registry
 
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 17f26e1..afb6e0f 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -14,7 +14,7 @@ Currently supported: **Claude Code**, **Codex**, **GitHub Copilot CLI**
 Each rule lives in its own directory with three parts:
 
 ```
-core/structure/instruction-file-size-limit/
+core/structure/root-instruction-file-presence/
   rule.md          # Definition: frontmatter (id, type, level, checks) + prose
   rule.yml         # OpenGrep patterns (or empty `rules: []` for mechanical)
   tests/
@@ -24,12 +24,12 @@ core/structure/instruction-file-size-limit/
 
 ## Coordinates
 
-Every rule has a coordinate like `CORE:S:0005` — three parts:
+Every rule has a coordinate like `CORE:S:0001` — three parts:
 
 | Part | Meaning | Values |
 |------|---------|--------|
-| Namespace | Who owns it | `CORE`, `CLAUDE`, `CODEX` |
-| Category | What it checks | `S` (structure), `C` (content) |
+| Namespace | Who owns it | `CORE`, `CLAUDE`, `CODEX`, `COPILOT` |
+| Category | What it checks | `S` (structure), `C` (content), `G` (governance), `M` (maintenance) |
 | Slot | Sequence number | `0001`–`9999` |
 
 Check `registry/coordinate-map.yml` to see which slots are taken before picking a new one.
@@ -38,9 +38,9 @@ Check `registry/coordinate-map.yml` to see which slots are taken before picking
 
 | Type | How it detects | Example |
 |------|---------------|---------|
-| **mechanical** | Python structural checks (file exists, line count, byte size) | CORE:S:0001 — instruction file exists |
-| **deterministic** | OpenGrep pattern matching on file content | CORE:C:0006 — specificity over vagueness |
-| **semantic** | OpenGrep pre-filter + LLM evaluation | CORE:C:0017 — repo-specific content |
+| **mechanical** | Python structural checks (file exists, line count, byte size) | CORE:S:0001 — root instruction file presence |
+| **deterministic** | OpenGrep pattern matching on file content | CORE:C:0004 — avoid generic placeholder content |
+| **semantic** | OpenGrep pre-filter + LLM evaluation | CORE:C:0001 — include project context |
 
 Mechanical rules have `rules: []` in their rule.yml. Deterministic and semantic rules have OpenGrep patterns.
 
@@ -103,13 +103,15 @@ All tests must pass before submitting.
 
 ```
 core/
-  structure/       # 12 rules — file existence, size, format
-  content/         # 18 rules — what instruction files should contain
+  structure/       # 3 rules — file presence, nesting, format
+  content/         # 5 rules — context, commands, architecture, constraints
+  governance/      # 1 rule — cross-agent compatibility
+  maintenance/     # 2 rules — reference integrity, glob validation
 
 agents/
-  claude/rules/    # 10 rules — CLAUDE.md-specific patterns
-  codex/rules/     #  7 rules — AGENTS.md-specific patterns
-  copilot/rules/   # 25 rules — copilot-instructions.md patterns
+  claude/rules/    # 3 rules — CLAUDE.md-specific patterns
+  codex/rules/     # 1 rule — AGENTS.md-specific patterns
+  copilot/rules/   # 2 rules — copilot-instructions.md patterns
 ```
 
 Opinionated rules (governance, style) live in [reporails/recommended](https://github.com/reporails/recommended) with the `RRAILS_` namespace.
diff --git a/README.md b/README.md
index 0fa7e16..2fc0362 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 Validation rules for AI agent instruction files (CLAUDE.md, .cursorrules, copilot-instructions.md).
 Community-maintained.
 
-**Version:** 0.3.1 <!-- source of truth: VERSION file -->
+**Version:** 0.4.0 <!-- source of truth: VERSION file -->
 
 ### Pre-1.0 — moving fast, API still evolving, feedback welcome.
 
@@ -26,20 +26,24 @@ npx @reporails/cli check
 ## What's here
 ```
 core/
-  structure/     # 12 rules: File organization, size limits, modularity
-  content/       # 18 rules: Clarity, completeness, specificity
+  structure/     # 3 rules: File presence, nesting, format
+  content/       # 5 rules: Context, commands, architecture, constraints
+  governance/    # 1 rule: Cross-agent compatibility
+  maintenance/   # 2 rules: Reference integrity, glob validation
 
 agents/
-  claude/        # 10 rules: Claude Code specific
-  codex/         # 7 rules: OpenAI Codex specific
-  copilot/       # 25 rules: GitHub Copilot CLI specific
+  claude/        # 3 rules: Claude Code specific
+  codex/         # 1 rule: OpenAI Codex specific
+  copilot/       # 2 rules: GitHub Copilot CLI specific
 
 schemas/         # Rule, agent, and config schemas
 registry/        # Capabilities, levels, coordinate map
 docs/            # Capability levels, sources
 ```
 
-47 core rules. For additional recommended rules, see [reporails/recommended](https://github.com/reporails/recommended).
+17 rules. For additional recommended rules, see [reporails/recommended](https://github.com/reporails/recommended).
+
+> **Tombstones**: Old coordinate slots from pre-0.4.0 rules will be backfilled in `registry/tombstones.yml` after 0.5.0.
 
 ## Contributing
 
diff --git a/VERSION b/VERSION
index a2268e2..1d0ba9e 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.3.1
\ No newline at end of file
+0.4.0
diff --git a/docs/capability-levels.md b/docs/capability-levels.md
index bcd8e1e..6e5cfe7 100644
--- a/docs/capability-levels.md
+++ b/docs/capability-levels.md
@@ -116,13 +116,13 @@ Rules and capabilities are **separate systems** connected only by the level iden
 
 This means an L3 project is checked against all rules at L1, L2, and L3 — not just L3 rules.
 
-**47 rules** across 3 types:
+**17 rules** across 3 types:
 
 | Type | Count | Detection Method | LLM Cost |
 |------|-------|------------------|----------|
-| Mechanical | 22 | Python structural checks | None |
-| Deterministic | 18 | OpenGrep pattern match | None |
-| Semantic | 7 | OpenGrep gate + LLM evaluation | Per check |
+| Mechanical | 6 | Python structural checks | None |
+| Deterministic | 10 | OpenGrep pattern match | None |
+| Semantic | 1 | OpenGrep gate + LLM evaluation | Per check |
 
 ---