diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2ebece1..b4f5ef9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,16 +10,32 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - `thinktank run` command — spawn N parallel Claude Code agents in isolated worktrees
 - `thinktank apply` command — apply recommended or selected agent's changes
+- `thinktank apply --preview` — review diff with syntax highlighting before applying
+- `thinktank compare <A> <B>` — compare two agents' diffs side by side
 - `thinktank list` command — view last run's results
 - Convergence analysis with diff-content comparison (Jaccard similarity + union-find clustering)
 - Unified diff parser for structured change extraction
-- Recommendation scoring: test results > convergence > diff size
-- Test runner with command parsing, error detection (ENOENT, timeout), and pre-flight checks
+- Recommendation scoring: test results (100pts) > convergence (50pts) > diff size (10pts)
+- Test runner with command parsing, shell injection prevention, and ENOENT detection
+- CLI input validation: attempts (1-20), timeout (10-600s), model warnings
+- Architecture documentation (`docs/architecture.md`)
 - CI pipeline with GitHub Actions (Node 22/24, build, lint, typecheck, test)
+- CI hardening: npm audit, build output verification
 - CodeQL security scanning
+- npm publish workflow with provenance on version tags
 - Biome for TypeScript linting and formatting
-- 31 unit tests across convergence, diff parsing, test runner, and apply command
+- Cross-platform color support via picocolors (NO_COLOR, Windows cmd.exe)
+- 56 unit tests across convergence, diff parsing, test runner, apply, git utils, display
 - YAML-based issue templates (bug report, feature request)
 - PR template, CONTRIBUTING.md, SECURITY.md, CODE_OF_CONDUCT.md
 - CLAUDE.md with project architecture and conventions
 - VS Code configuration with Biome formatter
+
+### Security
+- Test command validation rejects shell operators (`;|&\`><`) to prevent injection
+- Result files written with mode 0o600 and agent stdout/stderr redacted
+- Branch names use crypto.randomUUID() to prevent collision
+- Diff parser handles quoted paths (filenames with spaces)
+
+### Removed
+- Unused `getCurrentBranch()` and `applyDiff()` exports