Marp Deck Generator

Purpose

Assemble the final MARP deck by applying:

planned structure
finalized layout decisions
materialized visuals (diagrams/images)

This skill performs no planning, no interpretation, no visual design.

It is a deterministic renderer.

Inputs and outputs

Inputs (all mandatory)

definition/deck-definition.md
Semantic intent and authoritative content scope
planning/deck-plan.md
Slide sequence and content intent
planning/deck-visual-design.md
Authoritative layout and visual execution

If any input is missing → stop and report the error.

Outputs

slides/deck.md (required)
slides/deck-notes.md (required)
.marp/themes/deck-theme.css (only if a new class is explicitly required)

Required references (hard dependencies)

Read and follow exactly — both are mandatory:

.marp/references/deck-template.md — the how: CSS classes, Markdown/HTML syntax, layout legality, density caps.
.marp/references/brand-style-guide.md — the what and why: cover/section tone guidance, callout patterns, breadcrumb format, emoji rules, logo variant rules, brand color usage.

If either file cannot be found, stop immediately and report the missing file.

Do not guess or re-implement rules from either reference.

Also read: .marp/themes/deck-theme.css

Use it to make render-safe choices (title wrapping, density modifiers, image fit) while staying within the template's allowed classes and patterns.

Authority and precedence rules

When sources conflict, apply this strict order:

deck-template.md → layout legality (classes that exist; Markdown/HTML rules)
- includes the effective behavior implied by .marp/themes/deck-theme.css
brand-style-guide.md → brand compliance (tone choices, callout labels, emoji, breadcrumbs)
- cannot override what the template forbids, but constrains choices within the allowed set
deck-visual-design.md → layout & visuals per slide
deck-plan.md → content intent
deck-definition.md → semantic boundaries

Never override a higher-priority artifact.

Workflow

1. Validate structural alignment

Before rendering:

Slide count must match between:
- planning/deck-plan.md
- planning/deck-visual-design.md
Slide order must be identical
Titles and section boundaries must align

If not → stop and report mismatch.

2. Build deck skeleton

Create slides/deck.md with:

Required MARP metadata header
Frontpage slide (structure unchanged; cover variant may vary)
Closing slide (unchanged)

Insert all user slides between frontpage and closing.

Cover and section style preferences

Use the cover and section variant MARP class tokens exactly as listed in .marp/references/deck-template.md.

Selection rules (deterministic):

If definition/deck-definition.md includes an explicit preference (recommended), use it:
- Style preferences: cover=<name>, section=<name>
- Example: Style preferences: cover=light, section=dark
Else, consult .marp/references/brand-style-guide.md §5 and apply the tone guidance there without overriding it.
- Only ask the user if the tone is still ambiguous after consulting the brand guide.
Apply the background selection policy in .marp/references/deck-template.md.

3. Render slides deterministically

For each slide (in order):

3.1 Section slides

If the slide is a section divider:

Use the class comment from the section variant table (e.g. )
Render only the section title as # Section Title
Ignore visuals and content

3.2 Standard slides

For each standard slide:

Layout

Read ## Layout from deck-visual-design.md
Map it to the closest valid pattern in deck-template.md
If no valid mapping exists → stop and report

Content

Render content strictly from planning/deck-plan.md
Use semantic Markdown or minimal HTML
Respect density and structure constraints

Visuals

If ## Image references an asset, insert it according to the layout context.

Slide class tokens (from visual design)

If planning/deck-visual-design.md includes explicit slide class tokens inside ## Layout (e.g. Slide class: content visual-split image-wide no-top-accent), render them verbatim as the slide class comment, as long as they are allowed by .marp/references/deck-template.md.

If a class is requested but not supported by the template, stop and report the mismatch.

Branded rendering patterns (brand-style-guide compliance)

Apply the following patterns exactly as defined in .marp/references/brand-style-guide.md:

Breadcrumbs → §9
Callout labels → §10 (class tokens from .marp/references/deck-template.md)
STEP labels → §9
Emoji → §11
Closing / tagline lines → §7

Render-safety modifiers (allowed, deterministic)

To prevent common theme-related rendering failures (overflow, cropped visuals), it is allowed to apply these additional modifiers even if they are not explicitly listed in deck-visual-design.md, as long as they are defined in .marp/references/deck-template.md and .marp/themes/deck-theme.css:

compact:
- Use when slide density is too high to fit at default typography.
- Never use it to hide content; if it still doesn’t fit, stop and report the slide as unrenderable.
image-wide / image-tall:
- Compute the image aspect ratio from the PNG header; apply image-wide or image-tall per the threshold rules in .marp/references/deck-template.md.
- Only apply when the slide class includes visual-split (or another image-centric pattern where it helps fit).

Slide title length rule (mandatory): Apply the slide title length rule from .marp/references/deck-template.md.

Respect the content budget hard caps defined in .marp/references/deck-template.md.

When the content budget is exceeded:

First reduce content (fewer bullets, shorter phrasing) — always preferred.
If all content is essential, add compact to the slide class token.
If the slide still exceeds budget with compact, stop and report the slide as unrenderable.

Use the image placement patterns and Markdown/HTML image syntax rules from .marp/references/deck-template.md.

4. CSS extension (exception-only)

Extend .marp/themes/deck-theme.css only if:

deck-visual-design.md explicitly requires a layout
AND no existing template class can express it

Rules:

Minimal, reusable classes only
No slide-specific CSS
Follow CSS extension rules in the template

If extension is optional → do not add it.

5. Generate presenter notes

Create slides/deck-notes.md:

One note block per slide
Same order as slides/deck.md
Notes must:
Summarize slide intent
Provide speaking cues
Avoid adding new content or interpretation

Notes must remain aligned with the plan, not the visuals.

Quality gates (mandatory)

Before finalizing:

Frontpage and closing slide structures are unchanged
Slide order and count match all inputs
Every visual reference resolves to an existing asset
No content appears that is not in the plan
No layout appears that is not allowed by the template
Slide density is moderate and readable
CSS is extended only when unavoidable
Vertical balance: every content slide must have its title near the top with body content flowing immediately below. A large whitespace gap between title and content signals the wrong layout class or a structural error in the HTML — do not patch by adding filler content. Verify the class tokens match the template mapping.
Bottom clearance: no content element (card, tile, bullet, or table row) may be clipped at the slide bottom. If content overflows: reduce text first → then add compact → then report as unrenderable.
Process-flow constraint: process-flow slides must not contain any content below the .flow-cards container. The baseline rail CSS extends below the card row; additional elements will overlap it or fall outside the safe area.
Brand compliance gate: verify all brand rules by re-reading .marp/references/brand-style-guide.md — do not rely on any inline summary.

The output must be render-ready and deterministic.

marp-deck-gen