error-log

name	error-log
description	Captures non-obvious errors and their solutions as structured Obsidian notes for future reference. Use when: (1) /error-log command to capture an error from the current session, (2) /error-log <error description> to log a specific error, (3) user wants to document a tricky bug fix or error resolution.
metadata	{"version":"1.0.0"}

Error Log — Capture Error Solutions to Obsidian

Analyze the current conversation for error -> investigation -> fix patterns, structure them as reusable troubleshooting notes, and save to the Obsidian vault.

Tools needed: Bash, Write, Read

Procedure

Follow these steps exactly. Do not skip steps or reorder them.

Step 1 — Read config

Run:

cd "$(git rev-parse --show-toplevel 2>/dev/null || pwd)"
python3 -c '
import sys, os
import glob; sys.path.insert(0, max(glob.glob(os.path.expanduser("~/.claude/plugins/cache/*/obsidian-brain/*/hooks")), default="hooks"))
from obsidian_utils import load_config
c = load_config()
if not c.get("vault_path"):
    print("ERROR: vault_path not configured", file=sys.stderr)
    sys.exit(1)
print("VAULT=" + c["vault_path"])
print("SESS=" + c.get("sessions_folder", "claude-sessions"))
print("INS=" + c.get("insights_folder", "claude-insights"))
'

Parse each output line as KEY=VALUE, splitting on the first =.

If the file does not exist or is invalid JSON, tell the user:

Config not found. Please run /obsidian-setup first to configure your Obsidian vault.

Stop here if config is missing.

Step 2 — Validate vault access

Run:

test -d "$VAULT_PATH/$INSIGHTS_FOLDER" && test -w "$VAULT_PATH/$INSIGHTS_FOLDER" && echo "OK" || echo "FAIL"

If FAIL, tell the user:

The insights folder $VAULT_PATH/$INSIGHTS_FOLDER does not exist or is not writable. Run /obsidian-setup to fix this.

Stop here if FAIL.

Step 3 — Identify the error

Check if the user provided an argument after /error-log.

• With argument (e.g. /error-log BrokenPipeError in subprocess): Use the description to search the current conversation for matching error context, investigation steps, and resolution.
• Without argument (bare /error-log): Scan the full conversation for error -> investigation -> fix patterns. Look for:
  • Stack traces, error messages, or exception output
  • Debugging steps taken (hypothesis, investigation, failed attempts)
  • The fix that ultimately resolved the issue
  • If multiple errors were resolved, present a numbered list and ask the user which to log

If no error pattern is found in the conversation, tell the user:

No error -> fix pattern detected in this session. You can run /error-log <description> to manually describe an error to document.

Stop here if no error is found.

Step 4 — Structure the error note

Draft the note body with these four sections. Each section should be concise but complete enough to be useful months later when encountering the same error:

• Error: The exact error message, symptoms, and context where it appeared (include relevant stack trace snippets or command output if available, formatted as code blocks)
• Root Cause: Why the error happened — the underlying reason, not just the surface symptom
• Fix: The specific change or command that resolved it — include code diffs, config changes, or commands as code blocks
• Prevention: How to avoid this error in the future — linting rules, config patterns, pre-checks, or design principles

Step 5 — Auto-generate topic tags

Based on the error content, generate 1-3 topic tags. Tags should be lowercase, hyphenated, and specific to the technology or domain. Examples:

• claude/topic/subprocess-pipes
• claude/topic/python-async
• claude/topic/npm-dependencies
• claude/topic/git-hooks

Step 6 — Show preview and ask for edits

Present the full note to the user including frontmatter:

---
type: claude-error-fix
date: YYYY-MM-DD
created_at: <ISO-8601-UTC>
source_session: <current-session-id>
source_session_note: "[[<session-note-filename>]]"
project: <project-name>
tags:
  - claude/error-fix
  - claude/project/<project-name>
  - claude/topic/<auto-generated-topic-1>
  - claude/topic/<auto-generated-topic-2>
---

# <Error Title>

## Error

<error message and symptoms>

## Root Cause

<why it happened>

## Fix

<what resolved it>

## Prevention

<how to avoid it in future>

Where:

• YYYY-MM-DD is today's date

• <ISO-8601-UTC> is the current UTC timestamp at second precision. Get it via:

  python3 -c 'from datetime import datetime, timezone; print(datetime.now(timezone.utc).isoformat(timespec="seconds"))'
  

  Example: 2026-04-24T18:42:11+00:00

• <current-session-id> and <session-note-filename> are derived together. Get session context via the shared helper:

  cd "$(git rev-parse --show-toplevel 2>/dev/null || pwd)"
  python3 -c '
  import sys, os
  import glob; sys.path.insert(0, max(glob.glob(os.path.expanduser("~/.claude/plugins/cache/*/obsidian-brain/*/hooks")), default="hooks"))
  from obsidian_utils import load_config, get_session_context
  c = load_config()
  ctx = get_session_context(c["vault_path"], c.get("sessions_folder", "claude-sessions"))
  print("SID=" + ctx["session_id"] + " HASH=" + ctx["hash"] + " PROJECT=" + ctx["project"] + " SESSION_NOTE=" + ctx["session_note_name"])
  '
  

  Parse the output to get SESSION_ID, HASH, PROJECT, and SESSION_NOTE.

  Important: If SESSION_ID is unknown, use unknown for source_session and omit source_session_note entirely.

• <project-name> is the PROJECT value from get_session_context() (lowercased, hyphenated basename of cwd)

• <Error Title> is a short, descriptive title for the error (e.g. "BrokenPipeError when piping subprocess output to head")

• The source_session_note field creates an Obsidian backlink to the source session note

Ask the user:

Preview above. Would you like to:

• save as-is
• edit tags — add or remove tags
• edit content — tell me what to change
• cancel — discard this note

Wait for the user's response. Apply any requested edits and show the updated preview. Repeat until the user says save or cancel.

If cancel, stop here.

Step 7 — Generate filename

Construct the filename from these parts:

1. Date: YYYY-MM-DD (today)
2. Slug: The error title, lowercased, spaces replaced with hyphens, non-alphanumeric characters (except hyphens) removed, truncated to 50 characters
3. Hash: 4-character hex hash derived from the current timestamp: date +%s | md5 | cut -c29-32 (macOS) or date +%s | md5sum | cut -c1-4 (Linux). Do NOT use tail -c 4 — it counts the trailing newline as a byte and returns only 3 visible characters.
4. Suffix: -error

Final filename: YYYY-MM-DD-<slug>-<hash>-error.md

Example: 2026-04-04-brokenpipeerror-subprocess-pipe-a3f2-error.md

Step 8 — Write the note

Run:

mkdir -p "$VAULT_PATH/$INSIGHTS_FOLDER"

Then use the Write tool to write the full note (frontmatter + body) to:

$VAULT_PATH/$INSIGHTS_FOLDER/YYYY-MM-DD-<slug>-<hash>-error.md

Then set permissions:

chmod 644 "$VAULT_PATH/$INSIGHTS_FOLDER/YYYY-MM-DD-<slug>-<hash>-error.md"

Step 9 — Confirm

Print:

Error fix logged!

• File: $VAULT_PATH/$INSIGHTS_FOLDER/<filename>
• Tags: claude/error-fix, claude/project/<name>, claude/topic/<topic1>, ...
• Open in Obsidian to view. This note will appear in the "Error Fixes" section of the Project Index dashboard.