c11-markdown

name: c11-markdown version: 1 description: Open markdown files in a c11 markdown surface with live reload. Use when you need to display plans, documentation, or notes alongside terminals and browser surfaces with rich rendering (headings, code blocks, tables, lists, Mermaid diagrams). Prefer this over external viewers when c11 is running.

c11 Markdown Surfaces

Use this skill to display markdown files in a c11 markdown surface — a first-class surface type that lives alongside terminal and browser surfaces in the same workspace, driven from the same c11 CLI. The binary is c11.

Rich rendering (headings, code blocks, tables, lists, Mermaid) with live file watching — the panel auto-updates when the file changes on disk.

Core Workflow

1. Write your plan or notes to a .md file.
2. Open it in a markdown panel.
3. The panel auto-updates when the file changes on disk.

# Open a markdown file as a split panel next to the current terminal
c11 markdown open plan.md

# Absolute path
c11 markdown open /path/to/PLAN.md

# Target a specific workspace
c11 markdown open design.md --workspace workspace:2

When to Use

• Displaying an agent plan or task list alongside the terminal
• Showing documentation, changelogs, or READMEs while working
• Reviewing notes that update in real-time (e.g., a plan file being written by another process)

Producing artifacts the operator will return to

When you are creating more than one markdown artifact across a session — a map, a proposal, an audit, a status report — present them as one navigable surface, not multiple disconnected top-level tabs. The hyperengineer is already running many agents in many tabs; your session should not become another navigation problem for them to solve when they come back from lunch.

Two patterns, in priority order:

Default: one consolidated file with sections

Write to a single /tmp/<task>-trail.md and append as the work progresses. The operator scrolls one document instead of switching tabs; the most current section sits on top so it is what they see first when they tab over.

# At the start of a multi-artifact piece of work, open the trail file once
c11 new-pane --type markdown --file /tmp/voice-trail.md
# → OK surface:35 pane:9 workspace:1

# Then write to that file as the work evolves — live-reload renders it.
# When new sections supersede earlier ones, put the new section at the top
# so the operator's first read is current truth, not stale context.

This is the right default unless the operator explicitly asks for separate files.

When you need multiple distinct files: tabs of the same pane

If the artifacts genuinely need to be separate files (different audiences, different lifetimes, downstream tooling reads them as units), add the second and subsequent ones as tabs of the existing markdown pane, not as new top-level panes:

# Capture the pane ref from the first open
c11 new-pane --type markdown --file /tmp/voice-map.md
# → OK surface:35 pane:9 workspace:1

# Add subsequent files as tabs of pane:9 — NOT new top-level tabs
c11 new-surface --type markdown --file /tmp/voice-wave-1.md --pane pane:9
c11 new-surface --type markdown --file /tmp/voice-audit.md --pane pane:9

The operator sees one markdown pane in the sidebar; the artifacts navigate as tabs of that pane. This is materially different from three c11 new-pane calls, which produce three sibling top-level tabs the operator has to context-switch between.

Always: title + description per surface

Whether it is one consolidated file or a tabbed pane, set c11 set-title and c11 set-description on every markdown surface immediately after opening it. The operator should know what they are looking at without opening it. See the top-level c11 skill's "Title and description" section for the conventions.

Close stale artifacts at session-end

If an early-session map document is superseded by a final audit, close the early surface (c11 close-surface --surface <ref>) so the operator's primary view shows the current truth. Leaving five surfaces open across a session because they were once useful is unkind to the next look.

Live File Watching

The panel automatically re-renders when the file changes on disk. This works with:

• Direct writes (echo "..." >> plan.md)
• Editor saves (vim, nano, VS Code)
• Atomic file replacement (write to temp, rename over original)
• Agent-generated plan files that are updated progressively

If the file is deleted, the panel shows a "file unavailable" state. During atomic replace, the panel attempts automatic reconnection within its short retry window. If the file returns later, close and reopen the panel.

Agent Integration

Opening a plan file

Write your plan to a file, then open it:

cat > plan.md << 'EOF'
# Task Plan

## Steps
1. Analyze the codebase
2. Implement the feature
3. Write tests
4. Verify the build
EOF

c11 markdown open plan.md

Updating a plan in real-time

The panel live-reloads, so simply overwrite the file as work progresses:

# The markdown panel updates automatically when the file changes
echo "## Step 1: Complete" >> plan.md

Recommended AGENTS.md instruction

Add this to your project's AGENTS.md to instruct coding agents to use the markdown viewer:

## Plan Display

When creating a plan or task list, write it to a `.md` file and open it in c11:

    c11 markdown open plan.md

The panel renders markdown with rich formatting and auto-updates when the file changes.

Routing

# Open in the caller's workspace (default — uses C11_WORKSPACE_ID)
c11 markdown open plan.md

# Open in a specific workspace
c11 markdown open plan.md --workspace workspace:2

# Open splitting from a specific surface
c11 markdown open plan.md --surface surface:5

# Open in a specific window
c11 markdown open plan.md --window window:1

Deep-Dive References

Rendering Support

The markdown panel renders:

• Headings (h1-h6) with dividers on h1/h2
• Fenced code blocks with monospaced font
• Inline code with highlighted background
• Tables with alternating row colors
• Ordered and unordered lists (nested)
• Blockquotes with left border
• Bold, italic, strikethrough
• Links (clickable)
• Horizontal rules
• Images (inline)

Supports both light and dark mode.