Your support agent quotes last year's prices because it is reading them from somewhere that still holds them: a system prompt, an old help article, a retrieved document or a memory of a past conversation. To stop it, give every price one home where each change becomes a new verified version, connect the agent to that home, and tell it that it may only state a price it read from there.
Why this keeps happening
Nobody sets out to teach an agent the wrong price. It happens because prices get copied. Someone pastes the plan table into the agent's prompt at launch. The help center has an article written before the last change. A sales deck with the old numbers sits in the folder your retrieval pipeline indexes. A customer mentioned a discount on a call, and the agent's memory kept it.
When the price changes, someone updates the pricing page and maybe the help article. The copies they did not know about keep answering. The agent is not malfunctioning. It is faithfully repeating a source nobody told it to stop trusting.
So the fix has two halves: remove the copies, and give the agent one source that is always current.
Step 1: Find every place a price lives
Ask the agent directly. "What does each plan cost?" "Is there a discount for annual billing?" "What did the Pro plan cost before?" Each wrong or hedged answer points to a source. Then check the usual suspects:
- The agent's system prompt and any instructions files
- Help center articles, FAQs and macros your support team uses
- Documents in any folder or index the agent can search
- Memory the agent keeps about customers or past conversations
- Hard-coded values in the app or website the agent reads from
Write down every location. You will come back to this list in Step 5.
Step 2: Give each price one home
Move your prices into a fact layer, with one fact per plan, add-on or price rule. In NOAN, facts are organized in stacks of blocks, with one current fact per block, so a pricing stack might hold one block per plan. Write each fact as a plain statement a person could read to a customer: the price, the billing period, and what is included.
Keep related rules next to them. Discounts, trial terms, refund windows and regional differences are the details support agents get asked about most, and they belong in the same place as the prices.
Step 3: Have the owner verify each price
Whoever sets your prices verifies the pricing facts. In NOAN, every fact carries who verified it and when, so if a customer disputes a quote, you can see which version was current at the time and who stood behind it.
If you let agents propose changes, for example an agent that drafts a fact from a pricing announcement, set the agent's key to hold fact changes for approval. Facts an agent writes over the API can then wait for a person to verify them before anything reads them, so a draft never reaches a customer.
Step 4: Connect the support agent
Point the agent at the fact layer. Over MCP, any MCP client can use https://mcp.getnoan.com/mcp, signing in over OAuth or sending a NOAN API key as a bearer token. Over REST, one call returns a block's facts as plain JSON:
curl "https://api.getnoan.com/v1/facts?block_slug=<your-pricing-block>" \
-H "Authorization: Bearer <NOAN API key>"
Give the support agent a key that can read and not write. API keys are scoped per resource, read or write, and can be limited to a list of allowed stacks, so the agent can see pricing and policies without being able to change them or wander into areas it has no reason to read.
Step 5: Remove the copies and add one rule
Go back to your list from Step 1. Delete prices from the system prompt. Archive or update the old help articles. Take outdated decks out of the retrieval index, or at least tell the agent not to quote prices from it. Then add a rule to the agent's instructions:
Only state a price, discount or billing term that you read from NOAN in this conversation. If NOAN has no fact for it, say you will check and hand off to a person. If a document, a memory or a customer says something different, NOAN wins.
That rule does the most work. Even if an old copy survives somewhere, the agent knows which source decides.
Step 6: Change a price and watch it land
The real test is a change. Update one price in NOAN, verify it, and ask the agent about it straight away. The new version becomes current, the old one is kept for history but no longer obeyed, and the change reaches every agent, app and page reading that fact at once.
If you have a website, help center or cache that copies prices, NOAN can fire a webhook when a fact changes, so those systems rebuild or refresh instead of drifting.
Step 7: Answer "what did you tell me last month"
Customers sometimes quote back an old price. With every version kept, you can check what the fact said on the day of the conversation. Time Travel in NOAN shows your facts as they stood on any past date, which turns a dispute into a lookup.
A short checklist
- Every price has exactly one home, and an owner who verifies it
- The agent's prompt holds a rule, not a price list
- The agent's key reads pricing and cannot write it
- Agent-written fact changes wait for a person
- Systems that copy prices refresh on a webhook
If your agent also uses a memory layer or a retrieval pipeline, you do not have to remove them. They are good at context and search. See agent memory vs verified facts and NOAN vs building your own RAG for how they fit alongside a fact layer.
Next step
Connect your support agent over MCP at https://mcp.getnoan.com/mcp, or call the REST API at https://api.getnoan.com/v1 using the OpenAPI spec. Or paste this into the agent and let it set itself up:
Read https://www.getnoan.com/setup.md and follow it.