Patterns 2 & 3: structured-task template and phased execution

Outcome-based prompting handles simple delegation well. But some tasks are complex enough that a single outcome sentence isn't enough structure — you need Cowork to understand scope, respect boundaries, follow a sequence, and self-validate before handing off results. Two patterns handle this: the structured-task template and phased execution with checkpoints.

Pattern 2: The structured-task template

This is the cleanest prompt structure for complex, multi-step work. Five parts, in this order:

OBJECTIVE — one measurable sentence. What does done look like? Name the output files and where they live.

SCOPE — which folder, which file types, what to include and what to skip. Explicit scope prevents Cowork from wandering into folders you didn't intend.

CONSTRAINTS — what not to do. Don't delete. Don't modify source files. Write outputs only to a specific location. If uncertain about something, record it rather than guessing.

PHASES — the sequence of major stages. Inventory first, then plan, then execute, then validate. Naming phases forces Cowork to propose a plan at the plan stage rather than diving straight into execution.

SUCCESS CRITERIA — how Cowork (and you) will know the task is complete and correct. Name the output files, describe what validates them, and specify what "no files were modified" means in concrete terms.

Here is a full example you can use as a template:

OBJECTIVE: Create out/report.md summarizing all docs in raw/ and extract decisions into out/decisions.csv.

SCOPE: Only .md and .txt files in raw/. Ignore tmp/ and archive/.

CONSTRAINTS: Do not delete anything. Do not modify files in raw/. Write new outputs only to out/. If unsure about a decision, leave the field blank and record the question in out/open_questions.md.

PHASES: (1) inventory files and detect formats, (2) propose a plan before executing, (3) execute, (4) validate by schema-checking the CSV.

SUCCESS CRITERIA: out/report.md exists with sections for each source doc. out/decisions.csv validates against the schema. No files in raw/ have been modified.

Notice what this prompt does not include: the how, the tool choice, or the step sequence within each phase. It describes the destination in five dimensions — what to produce, where to work, what to avoid, what stages to follow, and how to verify. Cowork fills in the path.

The constraints section is often underwritten. "Do not delete anything" and "write outputs only to out/" are the two constraints worth including in almost every task. They're cheap to write and they save you from the most common sources of unwanted output.

Pattern 3: Phased execution with checkpoints

The structured template embeds phases into a single prompt. The phased execution pattern splits those phases into separate messages — one checkpoint at a time.

Phase 1: "Read all files in the folder and give me a summary of what you found."

Phase 2: "Based on what you read, propose a plan. Don't execute yet."

Phase 3: "Execute the plan."

Three prompts. Three checkpoints. Each one a gate you control.

Phase 2 is where this pattern earns its value. Cowork proposes its plan in human-readable form before touching a single file. You read it. You correct it. You approve it. Only then does it execute. Any misunderstanding — a wrong assumption about file format, a scope interpretation you didn't intend, a structural choice that won't work — surfaces here, at zero cost. After execution, the same misunderstanding costs you the time to review bad output and re-run the task.

This is the same discipline as Cursor's Plan Mode, applied to knowledge work instead of code. The principle is identical: review the plan before the machine acts on it. The earlier you catch a wrong assumption, the cheaper it is to fix.

Use phased execution when:

• The task involves files you haven't fully described in your prompt
• The output will be reviewed by someone else and needs to be right on the first pass
• You're running a workflow for the first time and don't yet know all the edge cases

Once you've run a workflow several times and trust that Cowork reads it correctly, you can collapse the phases back into the structured-task template. The checkpoint discipline is for when you can't afford to get it wrong.