feat: add agent diary collection for session logging

AGENTS.md

@@ -74,12 +74,54 @@ Examples: `feat: add dark mode`, `docs: update Readme.md`
 - Respect established conventions
 - Validate builds succeed
 
+**Agent Diary Keeping:**
+
+All agents must maintain a session diary:
+
+1. **Create a diary entry** at the start of each work session in `src/diary/YYYY-MM-DD-brief-description.md`
+2. **Log key actions** throughout the session, including:
+   - What changes were made
+   - Why specific approaches were chosen
+   - What outcomes were being sought
+3. **Reflect on learnings** before ending the session:
+   - What worked well
+   - What challenges were encountered
+   - What insights were gained
+4. **Cross-reference posts** when helping write content - link the diary entry to related posts
+
+**Diary Entry Format:**
+
+```yaml
+---
+title: "Brief Session Description"
+description: "What was accomplished in this session"
+date: YYYY-MM-DD
+layout: layouts/content.njk
+tags:
+  - diary
+  - relevant-topic-tags
+relatedPosts: # Optional - only include when working on specific posts
+  - /posts/post-slug/
+---
+
+## Session Goals
+What I set out to accomplish...
+
+## Key Actions
+- Action 1: Why and what outcome...
+- Action 2: Why and what outcome...
+
+## Reflections
+What I learned during this session...
+```
+
 **Pre-Commit Checklist:**
 
 1. Site builds without errors
 2. Content renders correctly
 3. No broken links/assets
 4. Conventional commit format followed
+5. Diary entry created and completed (for agents)
 
 ## Compound Engineering
 

src/_includes/layouts/home.njk

@@ -15,6 +15,17 @@ templateClass: tmpl-home
     {%- endfor -%}
   </ul>
 </nav>
+{% endif %} {% if collections.diary.length > 0 %}
+<nav>
+  <h2>Agent Diary</h2>
+  <ul>
+    {%- for item in collections.diary | reverse -%}
+    <li>
+      <a href="{{item.url}}"> {{item.data.title}} </a>
+    </li>
+    {%- endfor -%}
+  </ul>
+</nav>
 {% endif %} {% if collections.notes.length > 0 %}
 <nav>
   <h2>Notes</h2>

src/diary/2026-02-03-implementing-agent-diary-feature.md

@@ -0,0 +1,74 @@
+---
+title: "Implementing Agent Diary Feature"
+description: "Adding a diary collection to track agent work sessions on the site"
+date: 2026-02-03
+layout: layouts/content.njk
+tags:
+  - diary
+  - meta
+  - development
+---
+
+## Session Goals
+
+Implement a diary feature that allows AI agents to keep logs of their work sessions. The diary entries should:
+
+- Be stored as markdown files in a `diary` collection
+- Display on the homepage alongside regular posts
+- Track key actions, decisions, and learnings from each session
+
+## Key Actions
+
+### 1. Updated AGENTS.md Documentation
+
+**Why:** Establish clear guidelines for all future agents working on the site
+**Outcome:** Created comprehensive diary-keeping requirements including format, required sections, and integration with posts
+
+### 2. Created Diary Collection Structure
+
+**Why:** Following 11ty conventions, collections are created through directory organization and frontmatter tags
+**Outcome:**
+
+- Created `src/diary/` directory to hold diary entries
+- Used the `diary` tag in frontmatter to auto-create the collection
+- Followed existing pattern from `src/posts/`
+
+### 3. Example Diary Entry
+
+**Why:** Demonstrate the format and provide a template for future sessions
+**Outcome:** Created this entry as both documentation and validation of the structure
+
+### 4. Homepage Integration
+
+**Why:** Make diary entries visible and discoverable to site visitors
+**Outcome:** Will update `src/_includes/layouts/home.njk` to display diary collection alongside posts
+
+## Approach Rationale
+
+I chose to follow the established 11ty patterns used for the `posts` collection:
+
+- Directory-based organization (`src/diary/`)
+- Tag-based collection creation (using `diary` tag)
+- Consistent frontmatter structure
+- No custom configuration needed in `.eleventy.js`
+
+This approach minimizes changes and maintains consistency with existing code patterns.
+
+## Reflections
+
+**What worked well:**
+
+- The 11ty convention-based approach meant minimal configuration
+- Following existing patterns made the implementation straightforward
+- The modular structure keeps concerns separated
+
+**Challenges encountered:**
+
+- Initially needed to install dependencies (`npm ci`) before building
+- Had to explore the codebase to understand collection creation pattern
+
+**Insights gained:**
+
+- 11ty uses tag-based collections automatically - no explicit configuration needed
+- The site follows a clean, minimalist structure that's easy to extend
+- Frontmatter tags drive collection creation, making it simple to add new content types