# Anthropic draws a line between workflows and agents. Where does your reading fit?

**Anthropic's December 2024 guide for people building AI agents opens by separating two things it calls “workflows” and “agents,” then recommends starting with the simplest thing that works — possibly no agentic system at all — and reaching for one of its five workflow patterns only once that isn't enough. One of those patterns puts a second LLM call in the reviewer's seat. This note is about that pattern, and about what the other four leave for you to read.**

## What the guide argues

Erik S. and Barry Zhang wrote “Building Effective Agents” for engineers deciding how to build with LLMs. It starts with a definition:

> “Workflows are systems where LLMs and tools are orchestrated through predefined code paths. Agents, on the other hand, are systems where LLMs dynamically direct their own processes and tool usage, maintaining control over how they accomplish tasks.”

Then its advice starts with restraint:

> “When building applications with LLMs, we recommend finding the simplest solution possible, and only increasing complexity when needed. This might mean not building agentic systems at all.”

For when more structure is needed, they describe five workflow patterns: prompt chaining (a task broken into a sequence of calls, with optional checks between steps), routing, parallelization, orchestrator-workers (one LLM breaks a task into pieces and hands them to worker LLMs, then combines the results), and evaluator-optimizer. That last one:

> “In the evaluator-optimizer workflow, one LLM call generates a response while another provides evaluation and feedback in a loop.”

Anthropic doesn't mention MarsDawn anywhere in this guide, and doesn't recommend any Markdown tool. `/agent-transparency/` already covers this guide's transparency principle and its “checkpoints” language in detail — this note doesn't repeat that ground. `/agent-transparency/` is also where the guide's line about human code review lives, in its proper context (an appendix about coding agents specifically).

## Our reading, not Anthropic's

Anthropic doesn't say who checks a workflow's final output once it's done, and none of this describes a document at all — it's an architecture decision for people building the thing. But the five patterns don't produce the same kind of file for you to read. Prompt chaining and routing are usually invisible plumbing; if anything reaches you, it's the chain's last output, same as any other single response. Orchestrator-workers is different: if your coding agent uses this pattern internally, what lands in your folder can be a document assembled from several separate worker calls stitched together by the orchestrator, and a mistake in one worker's slice can be easy to miss inside a summary that reads smoothly end to end.

Evaluator-optimizer is the one worth pausing on, because the guide puts a second LLM call where a human reviewer might otherwise sit. That's a legitimate way to catch a class of mistakes cheaply, but it's still a model checking a model against whatever criteria it was given — the same caveat other authors here raise about a model judging its own or another model's work. Nothing in the guide says a person should double-check the evaluator's verdict; it doesn't take a position on that at all. If you're the one reading what any of this hands back, “the loop approved it” and “I checked it” aren't the same sentence, even when the file in front of you looks identical either way.

## Where MarsDawn helps, and where it doesn't

MarsDawn doesn't know which workflow pattern produced a file, and it has no AI model inside — it won't run an evaluator step of its own, and it won't tell you whether the one Anthropic describes did its job. What it does: the Outline tab in the sidebar (View ▸ Show Sidebar, ⌃⌘S) lists the headings of a long, orchestrator-assembled file, and clicking one jumps there. The source and the rendered page sit side by side (⌘2) and scroll together, with Mermaid diagrams and KaTeX math drawn out rather than left as source. If the agent revises the file while you're reading, MarsDawn reloads it and keeps your place, as long as you have no unsaved edits of your own. Edit ▸ Copy Reference (⌥⌘C) copies your place as `docs/plan.md:42`, ready to paste back into the agent's chat.

## Try it

MarsDawn is on the Mac App Store. The free `marsdawn` command-line tool works today:

```
brew install redtear1115/tap/marsdawn
```

It exports Markdown to PDF without the app.

[Command Line](/cli/) · Know before you buy: [What MarsDawn doesn't do](/limits/)

## Next

- The rest of this guide's transparency principle and its checkpoints language: [Anthropic says agents should be transparent — so who reads what they lay out?](/agent-transparency/)
- Why agent output is hard to read in general: [Reading what your agent hands back](/reading-agent-output/)
- Back to the series: [Editor's reading notes](/reading-notes/)

## Sources

- Erik S. and Barry Zhang, “Building Effective Agents,” Anthropic, December 19, 2024: [https://www.anthropic.com/engineering/building-effective-agents](https://www.anthropic.com/engineering/building-effective-agents) (fetched and quoted 2026-09-26).

## More

- [MarsDawn](https://marsdawn.southern-light.dev/index.md): Read and review the Markdown your agent wrote, natively on Mac: live split preview, Mermaid, KaTeX, Quick Look, PDF export. Free to try, USD 4.99 once.
- [Features](https://marsdawn.southern-light.dev/features/index.md): A native Mac Markdown editor: live preview, Mermaid and math, themes, plus clean PDF and print pages for meetings, margin notes and paper records.
- [Your writing stays on your Mac](https://marsdawn.southern-light.dev/yours/index.md): MarsDawn has no account, no sync and no cloud. Your Markdown documents stay on your Mac, in the files and folders you choose.
- [Try free, pay once](https://marsdawn.southern-light.dev/pay-once/index.md): MarsDawn is free to download. Try everything for 14 days, then unlock it once for USD 4.99. No subscription, no account.
- [PDF export](https://marsdawn.southern-light.dev/pdf/index.md): Export Markdown as a PDF or print it on your Mac, with Mermaid diagrams and highlighted code. Page breaks avoid splitting short code blocks.
- [A Mac app](https://marsdawn.southern-light.dev/native/index.md): A Markdown editor that is a real Mac app: native windows and tabs, autosave, version history, Quick Look in Finder and a text editor that behaves like a Mac.
- [What MarsDawn doesn't do](https://marsdawn.southern-light.dev/limits/index.md): No sync, no editing on iPhone or iPad, no plugins, no accounts. Themes, but no custom CSS. Know before you buy.
- [Support](https://marsdawn.southern-light.dev/support/index.md): Get help with MarsDawn, the Markdown editor for macOS.
- [Privacy Policy](https://marsdawn.southern-light.dev/privacy/index.md): MarsDawn does not collect personal data. Your documents and settings stay on your Mac.
- [How to open .md files on Mac](https://marsdawn.southern-light.dev/view-markdown-on-mac/index.md): How to open a .md file on a Mac: double-click, set a default app, preview in Finder. For .md files an AI agent wrote, read them rendered in MarsDawn.
- [Mermaid preview on Mac](https://marsdawn.southern-light.dev/mermaid-preview-mac/index.md): See Mermaid diagrams drawn next to your Markdown on a Mac: live preview, Quick Look and PDF export. A broken diagram shows its error and the line.
- [Quick Look for Markdown](https://marsdawn.southern-light.dev/quicklook/index.md): MarsDawn's Quick Look renders Markdown in Finder when you press Space, with Mermaid, KaTeX and highlighted code. It keeps working after the trial ends.
- [Markdown to PDF](https://marsdawn.southern-light.dev/markdown-to-pdf/index.md): Convert Markdown to PDF on a Mac with the free marsdawn command-line tool. Install it with Homebrew and run one command: tables, math, Mermaid and code.
- [MarsDawn compared: VS Code preview, Obsidian, QLMarkdown, LynxOffice](https://marsdawn.southern-light.dev/vs/index.md): For anyone choosing how to read and review Markdown on a Mac, often what an agent wrote. Every cell below comes from the vendor's own pages or our own check, all on 16 October 2026; products change, so a cell can go stale. If you spot a mistake, write to the address on Support.
- [MacMD Viewer vs. MarsDawn](https://marsdawn.southern-light.dev/vs/macmd-viewer/index.md): MacMD Viewer is a read-only Markdown viewer for USD 19.99. MarsDawn edits and previews side by side: free for 14 days, then USD 4.99 once.
- [Best Markdown viewer for Mac (2026)](https://marsdawn.southern-light.dev/best-markdown-viewer-mac/index.md): Eight Markdown viewers for Mac compared by price, Mermaid, math, PDF, live reload, Quick Look and native vs Electron, with who each one suits.
- [Command Line](https://marsdawn.southern-light.dev/cli/index.md): The free marsdawn command-line tool for Mac: export Markdown to PDF from a shell, a script or an LLM agent, with JSON output. Install it with Homebrew.
- [marsdawn for agents](https://marsdawn.southern-light.dev/cli/agents/index.md): A reference for AI agents and scripts that call marsdawn to turn Markdown into PDF: commands, JSON output, schemas, exit codes and requirements.
- [Agent skill](https://marsdawn.southern-light.dev/cli/skill/index.md): One file your coding agent loads to open Markdown it wrote in MarsDawn for your review, and to install marsdawn, export Markdown to PDF and read the JSON result.
- [MCP server](https://marsdawn.southern-light.dev/cli/mcp/index.md): marsdawn has no AI model of its own, so it doesn't matter which agent wrote the Markdown. Call it from the CLI, a skill file, or the marsdawn-mcp MCP server: all three run the same export.
- [Token-efficient review](https://marsdawn.southern-light.dev/token-efficient-review/index.md): A person reviews the rendered page in MarsDawn, never read back into the agent's context. The tool call itself returns a compact JSON result, not the rendered content, so calling it is cheap too.
- [Viewing Markdown elsewhere vs. MarsDawn](https://marsdawn.southern-light.dev/vs/markdown-preview-tools/index.md): How MarsDawn compares to reading Markdown in VS Code's built-in preview, a browser extension, or Claude Desktop's file preview: what each renders, and what it takes to open one file.
- [Themes](https://marsdawn.southern-light.dev/themes/index.md): Four built-in preview themes, each light and dark, plus a curated gallery you open from Settings in MarsDawn for Mac. Quick Look uses your theme.
- [Build a theme](https://marsdawn.southern-light.dev/themes/new/index.md): Pick colours and a handful of style options, see them applied to a sample document live, and submit your theme as a GitHub issue. No install, no git.
- [Make a theme with your agent](https://marsdawn.southern-light.dev/themes/agents/index.md): MarsDawn theme reference for AI agents: each theme.json field with type and range, the CLI loop that checks and renders it, a hand-off link, and how to submit.
- [Theme gallery](https://marsdawn.southern-light.dev/themes/gallery/index.md): Browse preview themes for MarsDawn, each reviewed by the developer, filter them by scenario, and report a problem with one. Build your own in the browser.
- [Sharing exported PDFs](https://marsdawn.southern-light.dev/sharing-exported-pdfs/index.md): Export an agent's Markdown to PDF and hand it to a colleague who doesn't read Markdown and won't install anything. No syntax, no app and no account needed to open it.
- [Why AI output still needs a human reader](https://marsdawn.southern-light.dev/reviewing-ai-output/index.md): AI-written Markdown still has to be understood by a person, not trusted on sight. MarsDawn pairs the rendered page with the source, and draws Mermaid diagrams and KaTeX math, so structure is legible at a glance.
- [Reading what your agent hands back](https://marsdawn.southern-light.dev/reading-agent-output/index.md): AI agents hand back their work as Markdown: plans, specs, progress reports. What people who build agents say about checkpoints and failures, why that output is hard to read, and a five-minute checklist for reviewing a plan.
- [Agent transparency](https://marsdawn.southern-light.dev/agent-transparency/index.md): Anthropic's guide to building agents asks for transparency: show the planning steps. What it says, what it doesn't, and why the steps usually end up as a Markdown file someone has to read.
- [Reviewing an agent plan](https://marsdawn.southern-light.dev/reviewing-agent-plans/index.md): A six-step way to review the plan an AI agent hands you before it runs, in about five minutes and in any editor, with a worked example.
- [Agent design patterns](https://marsdawn.southern-light.dev/agent-design-patterns/index.md): Reflection, tool use, planning and multi-agent collaboration, as Andrew Ng described them, and what each tends to hand back for you to read.
- [Changelog](https://marsdawn.southern-light.dev/changelog/index.md): What changed in each version of the MarsDawn app and the free marsdawn CLI.
- [Roadmap](https://marsdawn.southern-light.dev/roadmap/index.md): What's in progress and what's next for MarsDawn on Mac, iPhone and iPad, by version. No dates, and unscheduled ideas are marked.
- [Editor's reading notes](https://marsdawn.southern-light.dev/reading-notes/index.md): Six short notes on what the people building AI agents actually argue — Anthropic, Chip Huyen, Lilian Weng, Harrison Chase, LangChain and Andrew Ng — and what each one means for the person who has to read what such an agent hands back.
- [Reading notes: Chip Huyen](https://marsdawn.southern-light.dev/reading-notes/chip-huyen-agents/index.md): Chip Huyen's January 2025 essay on agents splits their actions into read-only and write actions. Why that split is a fast way to spot the line in a plan worth a closer look before you approve it.
- [Reading notes: Lilian Weng](https://marsdawn.southern-light.dev/reading-notes/lilian-weng-llm-agents/index.md): Lilian Weng's widely cited 2023 survey describes an LLM agent as a brain plus planning, memory and tool use. What each part tends to leave behind for you to read, and the limitation she names in plans that don't adjust to surprises.
- [Reading notes: Harrison Chase](https://marsdawn.southern-light.dev/reading-notes/harrison-chase-what-is-an-agent/index.md): Harrison Chase's 2024 definition of an agent and his spectrum of agentic behavior, and his case for observability as a system moves along it — read from the side of whoever reads the file it hands back.
- [Reading notes: LangChain (Jess Ou)](https://marsdawn.southern-light.dev/reading-notes/langchain-what-is-an-agent/index.md): LangChain's 2026 “What is an AI agent?” by Jess Ou echoes Harrison Chase's 2024 definition and describes a pipeline for evaluating agents automatically. Where that pipeline still hands a step to a person, and where it doesn't.
- [Reading notes: Andrew Ng](https://marsdawn.southern-light.dev/reading-notes/andrew-ng-design-patterns/index.md): Across five letters in The Batch, Andrew Ng ranks reflection, tool use, planning and multi-agent collaboration by how reliable and predictable he finds each one — and what that ranking suggests about how closely to check each one's output.
- [Templates](https://marsdawn.southern-light.dev/templates/index.md): Markdown templates for the documents an agent writes and you read: a spec, a flowchart and meeting notes, each with a prompt for your agent.
- [Spec template](https://marsdawn.southern-light.dev/templates/spec/index.md): A Markdown spec template with requirements, a Mermaid flow diagram and acceptance criteria. Your agent fills it in; you review it in MarsDawn.
- [Flowchart template](https://marsdawn.southern-light.dev/templates/flowchart/index.md): A Mermaid flowchart template in Markdown, with the steps written out below it. Preview it on a Mac and export it to PDF.
- [Meeting notes template](https://marsdawn.southern-light.dev/templates/meeting-notes/index.md): A Markdown meeting notes template with decisions and action items, each with an owner. Your agent writes it up; you check it in MarsDawn.
- [繁體中文](https://marsdawn.southern-light.dev/zh-hant/reading-notes/anthropic-building-effective-agents/index.md): Anthropic 在 2024 年 12 月發表的指南把 workflow 和 agent 分開來看，並描述了五種 workflow 模式，其中一種讓另一次 LLM 呼叫來審查。這對落進你資料夾的東西來說，意味著什麼。
- [简体中文](https://marsdawn.southern-light.dev/zh-hans/reading-notes/anthropic-building-effective-agents/index.md): Anthropic 在 2024 年 12 月发表的指南把 workflow 和代理分开来看，并描述了五种 workflow 模式，其中一种让另一次 LLM 调用来审查。这对落进你文件夹的东西来说，意味着什么。
- [日本語](https://marsdawn.southern-light.dev/ja/reading-notes/anthropic-building-effective-agents/index.md): 2024 年 12 月に Anthropic が発表したガイドは workflow と agent を分けて考え、5 つの workflow パターンを説明している。そのうち 1 つは、もう一回の LLM 呼び出しがレビューを担う。これは、あなたのフォルダに落ちてくるものにとって何を意味するか。
- [Deutsch](https://marsdawn.southern-light.dev/de/reading-notes/anthropic-building-effective-agents/index.md): Anthropics Leitfaden vom Dezember 2024 für Leute, die Agenten bauen, trennt Workflows von Agenten und beschreibt fünf Workflow-Muster, darunter eines, bei dem ein zweiter LLM-Aufruf den ersten prüft. Was das für Dateien in deinem Ordner bedeutet.
- [Français](https://marsdawn.southern-light.dev/fr/reading-notes/anthropic-building-effective-agents/index.md): Le guide d’Anthropic de décembre 2024 pour qui construit des agents sépare workflows et agents et décrit cinq patrons de workflow, dont un où un second appel LLM relit le premier. Ce que cela signifie pour ce qui atterrit dans votre dossier.
- [Español](https://marsdawn.southern-light.dev/es/reading-notes/anthropic-building-effective-agents/index.md): La guía de Anthropic de diciembre de 2024 para quien construye agentes separa workflows de agentes y describe cinco patrones de workflow, incluido uno en el que una segunda llamada a un LLM revisa la primera. Qué significa eso para lo que aterriza en tu carpeta.
- [한국어](https://marsdawn.southern-light.dev/ko/reading-notes/anthropic-building-effective-agents/index.md): 2024년 12월 Anthropic이 에이전트를 만드는 사람을 위해 낸 가이드는 workflow와 agent를 나누고, 그중 하나가 두 번째 LLM 호출로 첫 번째를 검토하는 다섯 가지 workflow 패턴을 설명합니다. 그게 폴더에 떨어지는 파일에 무엇을 뜻하는지.