compono

Agent-oriented, code-based PPTX generation. Describe a deck as typed primitives — an LLM agent never writes raw coordinates or touches OOXML.

compono lets an LLM agent (or a human) describe a slide deck as data — headers, bullet text, stats, tables, charts, images, process sequences, shapes — and get back a real, editable .pptx file. The agent never writes raw x/y/w/h coordinates: a constraint-based layout resolver computes every position from a small set of typed primitives.

Every rendered element is a genuine, editable native shape (p:sp, p:pic, p:graphicFrame) — never a flattened image or embedded video. Open the result in PowerPoint and drag a box around; it's a real object, not a picture of one.

Why compono

Ask an LLM to write raw python-pptx (or drive a browser-based renderer like pptx.js) and you get code littered with hand-picked EMU coordinates — the model has to simultaneously invent content and do pixel-perfect layout math it's genuinely bad at. The usual failure modes: overlapping boxes, text running off the slide, margins that drift slide to slide, titles crammed against the edge. None of that is a content problem; it's a coordinates problem.

compono removes coordinates from the agent's job entirely:

• You describe intent, not geometry. {"primitive": "grid", "columns": 2, ...}, not left=Inches(0.6), top=Inches(1.9), width=.... A directional, flexbox-style resolver computes every real position.
• A cheap pre-flight check, before paying render cost. validate(spec) catches schema errors, layout impossibilities, and text overflow — measured against real glyph metrics, not guessed — in milliseconds, with no file write. Bad specs get a structured {slide, primitive, field, error, detail, fix} back, not a broken .pptx or a stack trace.
• A design-quality pass, still optional. review(spec) — contrast, whitespace, image-fit, font-size-near-overflow, style — flags things a human designer would notice that "renders successfully" doesn't catch.
• Nothing is ever a flattened image. Every primitive is a real, editable OOXML shape or graphicFrame. A generated table is a real table; a generated chart has live, editable series data. Open the file and it's actually still a deck, not a picture of one.

The result: an agent's job shrinks to "pick the right primitives and content," and a resolver + validator handle everything spatial.

Install

pip install compono
# or
uv add compono

Quickstart

from compono import render_deck

spec = {
    "slides": [
        {
            "header": {"title": "Q3 Results", "subtitle": "Engineering team"},
            "body": [
                {
                    "primitive": "text",
                    "mode": "bullets",
                    "content": [
                        "Shipped the new layout resolver",
                        "Cut render time by 40%",
                        "Zero overflow bugs in production",
                    ],
                    "emphasis_indices": [1],
                }
            ],
        }
    ]
}

report = render_deck(spec, "deck.pptx")
print(report.pptx_path, report.warnings)

Or from the command line:

compono validate spec.json
compono render spec.json -o deck.pptx

How an agent should use this

The intended loop is validate, fix, render — not "render and hope":

1. Build a spec (plain dict/JSON — whatever your tool-calling naturally produces).
2. validate(spec) — cheap, no file write. If .valid is False, apply each error's fix field directly and re-validate.
3. Optionally review(spec) once it validates — apply suggestions that matter for this deck, ignore the rest; it never blocks anything.
4. render_deck(spec, output_path) — writes the real .pptx. It refuses to write anything on a validation failure, so a broken spec never produces a broken file.

compono reference (or compono.reference() in Python) prints the same full reference an MCP client or Claude Code skill would get — useful if you're wiring up a different agent framework and want the whole primitive catalog and error shape in one shot.

Documentation

• Getting started — install, quickstart, core concepts
• API reference — verbs, error shape, the feedback loop, design review
• Primitives — full catalog, image placeholders, worked examples
• Templates and fonts — Deck.template, font_family
• CLI
• MCP server — compono-mcp, and what to do when compono has no context
• Claude Code plugin
• Examples — rendered screenshots across genres, from real examples/*.json specs

(Absolute links, not relative — this README is also rendered as-is on PyPI, which can't resolve links to other files in the repo.)

Agents: the full reference in one file is compono reference / compono.reference(), or skills/compono/SKILL.md — that's the doc written for you, not this page.

Contributing

See CONTRIBUTING.md for dev setup, branching, and code style. If you're using Claude Code, .claude/README.md describes the build-workflow skill, review subagent, and commit/format hooks set up for this repo.