Attach a File to Chat, or Add to a Knowledge Base?

You have a document in front of you and a question you want an agent to answer from it. Insulin gives you two homes for that document: attach it to the current chat, where it informs this one conversation, or add it to a knowledge base, a reusable source an agent searches and cites across every conversation. This post is the decision — which one your document needs, and why.

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The two actions sit inches apart in the interface — a paperclip on the message box, a knowledge base in the agent’s settings — and they feel interchangeable the first time you reach for either. They are not. One loads a document for the conversation in front of you; the other stands a document up as something an agent consults again and again, long after this chat is closed.

Pick the wrong one and nothing breaks loudly. You just find yourself re-attaching the same policy to every new conversation, or wondering why a file you dropped into one chat last week is nowhere to be found in this one. The fix is to decide by what the document is for, not by which control is closer to your cursor. Here is the rule, then the table, then the edges.

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What attaching a file to the chat does

Attaching a file to the chat adds a document to this one conversation. You attach it with the paperclip on the message box, by dragging it in, or by pasting it — up to 10 files per message, each up to 25 MB. Once you send the message, the file belongs to that conversation’s Files tab, where anyone in the conversation can download it or open it in Preview.

The defining property is scope: an attached file is context for the conversation you attached it to. It is exactly the right tool for a one-off question — summarise this vendor quote, pull the renewal date out of this contract, what changed between these two versions — where the document matters for the thread in hand and nowhere else. This is the “ephemeral task context” an agent should hold for one task and no longer: it informs the current run and does not become a durable source the agent carries into unrelated work.

Because the scope is the conversation, so is the reach. An attached file is not indexed into a searchable source, it is not something a different agent in a different chat can find, and it is not a thing you maintain — it is the copy you sent, in the thread you sent it to.

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What adding a document to a knowledge base does

A knowledge base is a named collection of documents that agents can search across conversations, and it cites the source document for each answer. You add a document to a base, wait for its status to reach Indexed — the point at which it becomes searchable — then attach the base to an agent. From then on the agent searches that base whenever it is relevant, in every conversation it works in, and returns the document it drew each answer from.

That is a reusable source, not a one-time attachment. It is the right home for the material a team asks about repeatedly — approval policy, pricing and packaging, runbooks, contract templates, the meaning of internal terms. Load it once, and the agent answers from it everywhere, grounded in your own documents and citing what it used rather than answering from the model’s general training.

Two things follow from “reusable” that a chat attachment does not have. First, a base is searched and cited: a wrong answer points at the document it came from, so you can open it and check. Second, a base has scope you set per agent — a custom agent reaches only the bases you attach to it, which is how you keep a pricing floor in front of the agents that should see it and away from the ones that should not.

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The decision table

Start from what you have and what you need from it. The document points to its own home.

You are holding…	And you need…	Do this	Why
A quote, contract, or file for one question	An answer in this conversation	Attach it to the chat	Context scoped to the thread; nothing to maintain afterward
A policy or runbook a team asks about repeatedly	An agent to answer from it across conversations	Add it to a knowledge base, then attach the base to the agent	A searchable, cited source the agent reuses everywhere it works
A document your team keeps editing at its source	The agent’s answers to stay current as it changes	Add it to a base on a synced connector (GitHub, ClickUp, Google Drive)	Connectors are swept about once an hour; an uploaded copy or a crawled website does not auto-sync
Material for one team channel	Everyone in the channel to work from the same document	Attach it in the channel, or connect a channel knowledge base	Everyone in the channel sees the same messages; a channel knowledge base makes the source searchable there

The middle two rows are where most mistakes live, so they are worth saying plainly.

A document people keep editing does not want to be uploaded. Upload it and you have frozen a snapshot — it will still be there, still be cited, and still look authoritative six months after someone revised the original, because an uploaded file and a crawled website both sit still until you re-sync them by hand. If the document has a living home in GitHub, ClickUp, or Google Drive, connect that source instead: Insulin sweeps connectors with auto-sync enabled about once an hour, so the agent’s answers move when the document does.

Material for one team belongs where the team is. If a document is for a launch channel or an incident channel, attach it there — everyone in the channel sees the same messages, so the file is in the shared thread the whole team is already reading. When that material is something the channel’s agents should search and cite, not just read once, a channel can connect a knowledge base for exactly that.

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Two failure modes the table prevents

The point of deciding up front is to avoid the two quiet ways this goes wrong.

Re-attaching the same document to every conversation. If you find yourself dropping the refund policy into chat after chat, the document is not one-off context — it is a durable source wearing a chat attachment’s clothes. Put it in a knowledge base once and attach the base to the agent; you stop re-attaching, and every answer starts arriving with a citation you can check.

Expecting a chat attachment to be findable elsewhere. A file you attached to one conversation lives in that conversation’s Files tab. It is not indexed into a searchable source and another agent will not surface it. If “I want to find this again later, from somewhere else” is part of the need, that need is a knowledge base, and the signal to notice is the word again.

One rule captures both: if a document matters beyond a single conversation, it belongs in a knowledge base; if it matters only for the conversation in front of you, attach it and move on.

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Frequently asked questions

Should I attach a file to the chat or add it to a knowledge base? Attach a file when a document is for one conversation — a quote or contract you have a single question about. Add it to a knowledge base when an agent should search and cite it across many conversations, like a policy or runbook.

What happens to a file after I attach it to a chat? Once you send the message, the file belongs to that conversation’s Files tab, where anyone in the conversation can download it or open it in Preview. You can attach up to 10 files per message, each up to 25 MB.

Can another agent find a file I attached to a chat? No. An attached file is context for the conversation you attached it to. It is not indexed into a searchable source, so a different agent in a different conversation will not surface it. For that, add the document to a knowledge base.

My team keeps editing a document — should I upload it or connect it? Connect it. Add it to a knowledge base on a GitHub, ClickUp, or Google Drive connector, which Insulin sweeps about once an hour when auto-sync is on. An uploaded file and a crawled website do not auto-sync, so they age silently.

How do I share a document with everyone in a channel? Attach it in the channel — everyone in the channel sees the same messages, so it lands in the shared thread. If the channel’s agents should search and cite it rather than just read it once, connect a channel knowledge base.

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Takeaways

• Decide by what the document is for, not by which control is closer. A one-off question wants a chat attachment; a source a team reuses wants a knowledge base.
• A chat attachment is scoped to the conversation. It lands in that conversation’s Files tab, downloadable and openable in Preview — up to 10 files per message, 25 MB each — and no other agent will find it.
• A knowledge base is a reusable, cited source. Add a document, wait for Indexed, attach the base to an agent, and it searches and cites that document across every conversation.
• A document your team keeps editing wants a synced connector. Connectors sweep about once an hour; uploads and crawled websites do not auto-sync.
• Material for one team goes in the channel — everyone in the channel sees the same messages — or in a channel knowledge base when it should be searched and cited.

Insulin gives a document the home its job needs: the chat for this conversation, a knowledge base for every one. Explore Insulin knowledge bases, see how agents are scoped, or get a demo.