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What is an agent

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Next: The agent loop

A chatbot answers and waits. An agent keeps going: it looks things up, takes actions, and has to stop. The model is the AI that chooses the next step. The rest of this page is the other pieces you can point at in a product you already use.

Path Explorer
Time About 15 minutes
You need Nothing

What you will be able to do

  • Point at the six parts of an agent in a product you already use.
  • Tell a long chat from an agent by looking at tools, memory, and the stop rule.
  • See which part each reference is actually about.

The six parts

These six are a way to look at a product. A later page, Harness engineering, uses a different list of six. That list is what the system around the model does. This list is what you can name while you are still looking at the product.

Part What it is If it is missing
Model The component that chooses the next step from the text it can see You have a script, which can still be the right tool
Instructions The standing rules: role, format, what "done" means The model invents a new job on every turn
Tools Actions with a name and a side effect: read, search, write, call an API The model can only talk
Memory State that survives a step, and the state you mean to survive a session The next run starts from zero
Environment Where the loop runs: a laptop, a CI job, a remote machine, a browser You cannot say who can see the files or the keys
Stop The condition that ends the loop The run continues until the budget does

Tip

Established. Products market "agents" for very different stacks. The six parts are a way to look past the label. A chatbot with a search button is an agent only for as long as it is looping on a goal. A nightly job that opens a repo, runs tests, and opens a pull request is an agent even if nobody called it one.

A chat and an agent, side by side

A chat turn An agent run
Input Your message A goal, plus whatever the tools just returned
Work One reply Many steps
Side effects The reply itself Files, tickets, messages, pull requests
What remains The transcript, until the window fills Whatever the agent wrote to memory on purpose
End You send the next message A stop rule fires

Both use a model. The agent adds a loop, tools, and a place for the outcome to live.

A miniature

Goal: "Turn these three posts into one page a teammate can trust."

Part In this miniature
Model Chooses whether to read another post or to write
Instructions Cite the URL. Mark unverified claims. One page, not three essays.
Tools Open a post, write a markdown file
Memory The page itself, plus a line in an index
Environment Your repo, on your machine or in a cloud run
Stop The page has sources, and every number is marked

That miniature is also how this repository is maintained. The long version is wiki memory.

Where the references push

The ten posts from 8–10 October 2026 each lean on one part. The rest of the guide unpacks them. None of these one-liners are a verdict. They are a table of contents.

Source The part it presses on
@fleyta88, wiki memory Memory as files, not as a longer transcript
@ClaudeDevs, managed workflows One plan across many models
@Bober_smart, OmniRoute Tools and model access behind one local API
@N01ennn, motion skills Instructions packaged as skills
@ryancarson, cloud agents The environment: a seat on a laptop, or a remote run
@oliviscusAI, @thesupermannx The model, made cheap enough to run nearby
@antigenco, Antigen A loop whose side effects need a human gate
@himanshubuildss Libraries a builder's agent can copy from
@ai_explorer25 People to read. Kept in the community appendix

Check yourself

  1. Name the six parts without looking at the table.
  2. Take the last AI tool you opened. Which parts does it actually have?
  3. Which reference is about memory, and which is about where the run happens?

Sources

Established practice, organized for this guide. The rows above are signposts. Their claims are handled on the pages linked above.

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