Add checkpoint extension (#1947)

Co-authored-by: Aaron Sun <aaronsun@mac.lan>

Author: aaronrsun

extensions/README.md

@@ -78,6 +78,7 @@ The following community-contributed extensions are available in [`catalog.commun
 |-----------|---------|----------|--------|-----|
 | Archive Extension | Archive merged features into main project memory. | `docs` | Read+Write | [spec-kit-archive](https://github.com/stn1slv/spec-kit-archive) |
 | Azure DevOps Integration | Sync user stories and tasks to Azure DevOps work items using OAuth authentication | `integration` | Read+Write | [spec-kit-azure-devops](https://github.com/pragya247/spec-kit-azure-devops) |
+| Checkpoint Extension | Commit the changes made during the middle of the implementation, so you don't end up with just one very large commit at the end | `code` | Read+Write | [spec-kit-checkpoint](https://github.com/aaronrsun/spec-kit-checkpoint) |
 | Cleanup Extension | Post-implementation quality gate that reviews changes, fixes small issues (scout rule), creates tasks for medium issues, and generates analysis for large issues | `code` | Read+Write | [spec-kit-cleanup](https://github.com/dsrednicki/spec-kit-cleanup) |
 | Cognitive Squad | Multi-agent cognitive system with Triadic Model: understanding, internalization, application — with quality gates, backpropagation verification, and self-healing | `docs` | Read+Write | [cognitive-squad](https://github.com/Testimonial/cognitive-squad) |
 | Conduct Extension | Orchestrates spec-kit phases via sub-agent delegation to reduce context pollution. | `process` | Read+Write | [spec-kit-conduct-ext](https://github.com/twbrandon7/spec-kit-conduct-ext) |

extensions/catalog.community.json

@@ -73,6 +73,35 @@
       "created_at": "2026-03-03T00:00:00Z",
       "updated_at": "2026-03-03T00:00:00Z"
     },
+    "checkpoint": {
+      "name": "Checkpoint Extension",
+      "id": "checkpoint",
+      "description": "An extension to commit the changes made during the middle of the implementation, so you don't end up with just one very large commit at the end.",
+      "author": "aaronrsun",
+      "version": "1.0.0",
+      "download_url": "https://github.com/aaronrsun/spec-kit-checkpoint/archive/refs/tags/v1.0.0.zip",
+      "repository": "https://github.com/aaronrsun/spec-kit-checkpoint",
+      "homepage": "https://github.com/aaronrsun/spec-kit-checkpoint",
+      "documentation": "https://github.com/aaronrsun/spec-kit-checkpoint/blob/main/README.md",
+      "changelog": "https://github.com/aaronrsun/spec-kit-checkpoint/blob/main/CHANGELOG.md",
+      "license": "MIT",
+      "requires": {
+        "speckit_version": ">=0.1.0"
+      },
+      "provides": {
+        "commands": 1,
+        "hooks": 0
+      },
+      "tags": [
+        "checkpoint",
+        "commit"
+      ],
+      "verified": false,
+      "downloads": 0,
+      "stars": 0,
+      "created_at": "2026-03-22T00:00:00Z",
+      "updated_at": "2026-03-22T00:00:00Z"
+    },
     "cleanup": {
       "name": "Cleanup Extension",
       "id": "cleanup",