Buying or selling on Sigrix? You'll see five kinds of listings. They build on
each other like layers in a car: a prompt is a steering wheel, a skill is a
gearbox, an assistant is the driver who takes the wheel and works the gearbox,
an agent is the same driver running a route on their own, and a product is the
whole car bundled and ready to drive away.
§ 01 Prompt
A prompt is a single instruction you send to a model. The smallest
listing on Sigrix. Useful when you know exactly what you want the model
to do and you want the cleanest, cheapest result.
- One instruction, one response.
- Sometimes with a persona attached so the model speaks in a specific voice.
- Cheap to run, easy to compare side-by-side.
§ 02 Persona
A persona is a voice and a worldview the model adopts. A persona
listing on Sigrix is a reusable system prompt with character, tone, and
constraints baked in.
Think: "the editor of a quarterly magazine, terse and unimpressed" vs.
"a customer-success rep at a startup, warm and explicit." Same model,
very different output.
§ 03 Skill
A skill is a reference document — a SKILL.md file — that the model
can load into context to do a specific job. Skills do not run on their
own; they are tools that an assistant or agent picks up when needed.
A good skill listing on Sigrix bundles the file plus a worked example so
the buyer can see what "good" looks like.
§ 04 Assistant
An assistant is multi-turn. It holds a conversation, calls skills
when relevant, and works with the user step by step. Most of what people
picture when they say "AI" is an assistant: ChatGPT, Claude, a support
bot in the corner of a webpage.
Assistant listings on Sigrix ship with a persona, a list of skills, and
sample dialogues so the buyer knows what they're getting.
§ 05 Agent
An agent runs for you, not with you. You tell it the goal and
it executes the steps — calls tools, decides what to do next, hands you
back a finished result. Less back-and-forth, more autonomy.
Agents are the heaviest building block: more tokens, more time, more
risk of going off-track. Sigrix listings show the agent's tested
runbook so you can see exactly what it'll do.
§ 06 Product
A product is a bundle. It packages a persona, a few skills, an
assistant, and maybe an agent into a single listing with one price.
Products are the "ready-to-drive" tier — pick one, plug it in, ship.
> The five blocks compose: skills feed assistants, assistants and
> agents wrap into products. Pick the layer that matches the job.
One practical essay, every other Tuesday.
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