Most posts on this topic are written for developers. This one is for the marketer trying to decide where to put the thing they keep re-typing every Monday.
Claude gives you three places to put work: Skills, Projects, and the plain conversation. Most marketers I watch use one of them for everything, which means they are paying a tax on the other two not existing. The decision is not technical. The choice depends on one question: how often is this true?
Here is the entire decision tree, before any of the explanation. Save it.
That is the post. The rest is what to do when the line between two of them blurs, which is where most teams waste their setup time.
A Skill is a small bundle of instructions plus optional files that Claude loads on demand, across every conversation you have, in every Project. The mental model is: this is something Claude needs to know about how I work, not what I am working on this week.
The right test for a Skill is whether you would want it loaded if you opened a brand-new conversation to ask Claude something unrelated. If yes, it is a Skill. If no, it is a Project file.
Concrete marketer use cases:
The trap with Skills: people overload them with one-off knowledge ("here is what we sold last quarter"), which makes Skill descriptions stale within weeks. Skills are for the how. Projects are for the what.
If you have not built a Skill before, the four free ones on the Hub are the install template. Drag, drop, done. Each one is the structural shape of a Skill that does its job without bloat.
A Project is a workspace with its own system prompt and uploaded Knowledge files, pinned to a particular body of work. The mental model: this is the world Claude needs to live inside for the next 60 to 120 days.
The right test for a Project is whether the answer to the question "what is in your Knowledge files" is going to change before the year is out. If yes, it is a Project. If it is going to be true in five years, it should probably be a Skill, or written into the system prompt of a Project that uses the Skill.
Concrete marketer use cases:
The trap with Projects: people build one called "Marketing" and dump everything in. The Knowledge files start to contradict each other. Claude starts citing the launch from two quarters ago. The right move is more Projects with narrower scopes, not one Project with broader Knowledge. Specificity is the whole feature.
A plain conversation in the main Claude window, no Project, no Skills (or just the ones that auto-load). The mental model: this work is too small to deserve a home.
The right test for a plain prompt is whether you would feel silly building infrastructure for it. If yes, plain prompt it.
Concrete marketer use cases:
The trap with plain prompts is using them for everything because setup feels like overhead. The first hour you spend building one good Project for your current quarter pays itself back in a week. The first hour you spend on a Skill for your brand voice pays itself back the first time you brief out a campaign and the writing comes back sounding like you.
Marketers default to one of two extremes. One camp lives in plain prompts forever, copy-pasting the same brand voice instructions into every conversation, paying the setup tax every single time. The other camp builds one giant Project called "Marketing" and stuffs everything in, then wonders why Claude keeps citing a campaign from last year.
The fix is not more discipline. The fix is matching the work to the right container. Quarterly things live in Projects. Always-true things live in Skills. One-off things live in plain prompts. None of the three is the "real" answer. The system is the three together.
Here is a normal week for an in-house operator, with the right container for each task. The point is not that everyone's week looks like this. The point is that every task has a natural home, and forcing it into the wrong one is where time leaks.
Monday morning: weekly performance readout. Lives in the team's current-quarter Project, which has the KPI definitions, the campaign list, and last quarter's readout for context. The Brand Voice Skill loads so the readout sounds like the team, not like a McKinsey deck.
Tuesday: drafting a launch announcement for Q3. Open the Q3 Launch Project, which has the positioning doc, the messaging matrix, and the press kit. Brand Voice Skill auto-loads. Refusal Rules Skill auto-loads (no fake statistics, no horoscope copy).
Wednesday: a slack comes in asking what CTR looked like for last week's promoted post. Plain prompt. Paste the export, ask for the read. No Project needed.
Thursday: agency sends over a draft. You suspect it is over-hedged. Plain prompt with the draft pasted, asking for the three biggest improvements. Or, faster, run it through the Slop Sniffer and send the heatmap back.
Friday: someone asks for a one-pager summarising the next campaign. Open the Q3 Launch Project, ask for the summary, the Project has all the context. Done in 10 minutes.
Three Skills running quietly across everything (Brand Voice, Refusal Rules, Output Format). One active quarterly Project. Plenty of plain prompts for the rest. That is a sustainable Claude setup for a working marketer.
None of this matters until you have actually done the work that goes into each container. A Skill that contains a half-baked brand voice guide is worse than no Skill, because now every prompt inherits the half-bakedness. A Project full of stale Knowledge files is the same. The infrastructure is only as useful as the inputs.
If you have not extracted a real brand voice guide yet, do that first (the free Voice and Tone Extractor is built for this, and the sample output shows what good looks like). If your last KPI doc was from January, refresh it before you upload it to a Project. The container is plumbing. What flows through it is your judgment.
And before you build any of this, run the prompt audit on the prompts you would put inside. A bad prompt inside a Skill is a bad prompt running everywhere. The audit is the upstream check.
Voice Extractor, Competitive Teardown, SERP-Informed Brief, Performance Readout. Same four free prompts, packaged as installable Claude Skills with the YAML frontmatter and instructions already wired. CC BY 4.0. No email gate.
Open the Skills page