Knowledge Base Update Skill

When to Trigger

Activate this skill when any of the following occur:

• An architectural or tech-stack decision is made (and the why matters)
• A non-obvious bug is fixed (root cause + fix documented)
• A 3rd-party service/API has a quirk, limit, or gotcha discovered
• A project convention is established (naming, folder structure, patterns)
• A research question is answered after significant investigation
• A "we tried X and it failed because Y" moment happens

Step-by-Step Process

1. Identify the Entry Type

Choose the category that best describes what was learned:

2. Determine the File Path

Write to: .agent/knowledge/<slug>.md

• slug = kebab-case summary of the topic (e.g., auth-token-refresh-strategy)
• If an entry for this topic already exists, update it rather than creating a new file
• Group related topics under subfolders: .agent/knowledge/auth/, .agent/knowledge/infra/, etc.

3. Write the Entry

Use this exact template:

---
type: <decision|convention|bug|gotcha|research>
topic: <Short human-readable title>
date: <YYYY-MM-DD>
tags: [<tag1>, <tag2>]
---

## Summary
<One or two sentences — what was learned, bottom line up front>

## Context
<Why this came up. What problem were we solving?>

## Decision / Finding
<The actual content. Be specific. Include code snippets if helpful.>

## Rationale
<Why this choice over alternatives. What alternatives were rejected and why.>

## Consequences
<What does this affect going forward? What to watch out for?>

## References
- <File path, PR link, conversation snippet, or external URL>

4. Update the Index

After writing the entry, append a one-line summary to .agent/knowledge/INDEX.md:

| <date> | <type> | [<topic>](./<path>.md) | <one-line summary> |

If INDEX.md doesn't exist yet, create it with this header first:

# Project Knowledge Base

| Date | Type | Topic | Summary |
|------|------|-------|---------|

5. Confirm to User

After writing, report:

• What was saved and where
• The one-line summary that was added to the index

Rules

• Never summarize vaguely. "We decided to use X" is useless without why.
• Include the anti-pattern. If something was tried and rejected, document it — that's often the most valuable knowledge.
• Keep entries atomic. One topic per file. Don't bundle unrelated decisions.
• Date is mandatory. Future agents need to know how fresh this knowledge is.
• If in doubt, write it. The cost of a redundant entry is low. The cost of a missing one is re-doing the work.