fix-unclosed-fenced-block-en

Detect and fix unclosed fenced blocks ( ` ) in Markdown output. Fenced blocks are used for code, terminal output, file trees, config files, examples, and any verbatim content.

Problem description

When an AI assistant generates Markdown, it sometimes opens a fenced code block with ` (optionally followed by a language hint such as bash or markdown) but then omits the matching closing ` . The symptom is that the next heading or section renders inside the code block instead of as normal Markdown.

Typical broken pattern:

Some prose text.

skills-ref validate ./skills/my-skill

Next heading <-- should be outside the code block, but is not

---

## Detection algorithm

Scan the Markdown text **line by line** and maintain a simple toggle:

| State | Trigger | Action |
|-------|---------|--------|
| OUTSIDE | Line matches `` /^```/ `` | Switch to INSIDE, record line number and language hint |
| INSIDE  | Line matches `` /^```\s*$/ `` (closing fence) | Switch to OUTSIDE |
| INSIDE  | Line matches `^#{1,6} ` (ATX heading) | **Missing close detected** — insert ` ``` ` before the heading |
| INSIDE  | End of document reached | **Missing close detected** — append ` ``` ` at end |

> A closing fence must be **exactly** three or more backticks on their own
> line (optional trailing whitespace).  A line that starts with ` ``` ` but
> has additional non-whitespace characters is an **opening** fence.

---

## Fix procedure

### Step 1 — Identify all unclosed blocks

Apply the detection algorithm above to the full input text and collect every
location where a closing fence is missing.

### Step 2 — Insert closing fences

For each missing close (in reverse order so line numbers stay valid):

1. Insert a line containing exactly ` ``` ` immediately **before** the
   triggering heading (or at the end of the document).
2. Add a blank line after the inserted fence if one is not already present,
   to preserve heading spacing.

### Step 3 — Verify the result

Re-run the detection algorithm on the repaired text and confirm that no
unclosed blocks remain.

### Step 4 — Report

Tell the user:
- How many unclosed blocks were found and fixed.
- The approximate location of each fix (heading text or "end of document").

---

## Self-check before output

Before delivering **any** Markdown response, mentally (or literally) run the
detection algorithm on your own output.  If an unclosed block is found,
apply the fix before sending.

Checklist:
- [ ] Every ` ``` ` opener has a matching ` ``` ` closer on its own line.
- [ ] No ATX heading (`#` … `######`) appears between an opener and its closer.
- [ ] The document does not end while inside a fenced block.

---

## Examples

### Example 1 — heading triggers missing close

**Input (broken):**

Preserve language hints:

skills-ref validate ./skills/my-skill

## Citations

Fixed output:

Preserve language hints:

skills-ref validate ./skills/my-skill

## Citations

Example 2 — end of document triggers missing close

Input (broken):

Keep inline citation format:

According to the agentskills.io specification, the name field must match the directory name exactly.

**Fixed output:**

Keep inline citation format:

According to the agentskills.io specification, the `name` field must match
the directory name exactly.

---

## Edge cases

| Situation | Handling |
|-----------|----------|
| Nested backtick fences (four backticks) | Track fence depth; a four-backtick opener closes with four backticks |
| Inline backticks (single or double) | Ignored — only triple-backtick fences are relevant |
| Indented code blocks (4 spaces) | Not affected by this skill |
| Fence with language hint | Opening fence; closing fence has no hint |
| Multiple consecutive unclosed blocks | Fix each one individually in document order |

---

## Attribution

fix-unclosed-fenced-block-en — part of the roebi agent-skills library Author : roebi (Robert Halter), Switzerland License: CC BY-NC-SA 4.0 https://creativecommons.org/licenses/by-nc-sa/4.0/ Spec : https://agentskills.io/specification Source : https://github.com/roebi/agent-skills