Marketing reports 10K MQLs. Sales says 6K. Finance has another number. The fix isn't another spreadsheet. It's one defined metric, served everywhere.
Define each metric once with the formula, the filters, the edge cases, and the gotchas. Serve those definitions to every AI tool over MCP. Don't paste "MRR is X" into a system prompt, because that drifts. Define it once in a place every conversation reads.
Every team uses the same word to mean different things. Marketing's "qualified lead" is the one that filled out a demo form. Sales' "qualified" is the one with budget and timeline. Finance's "qualified pipeline" excludes anything beyond two quarters out. None of them are wrong; they're answering different questions.
AI walks into this without context and picks one. Whichever definition it pattern-matches from its training data, usually a generic SaaS-textbook definition that doesn't match any of your actual teams. The result: a fourth number that lines up with nobody.
The cost compounds. The boardroom argument is no longer about which team is right. It's about which AI is right. The data-team backlog fills up with "reconcile these numbers" tickets. Trust in AI degrades. Eventually someone says "let's just go back to dashboards."
A metric definition AI can use isn't a sentence. It's a structured record. Five required parts:
"Monthly Recurring Revenue (MRR)": committed monthly subscription revenue from active accounts, normalized for annual contracts.
The actual computation, in code that runs against your warehouse:
SELECT SUM(amount_cents / 100.0 / contract_months)
FROM subscriptions
WHERE status = 'active'
AND is_test = false Exclude test accounts. Exclude trials. Exclude paused subscriptions. Exclude internal-domain users. Whatever the rules are, they're part of the definition, not assumed knowledge.
Annual contracts divided by 12. Mid-cycle plan upgrades pro-rated to month-end. Free-trial-to-paid conversions counted from first payment, not signup. Each rule documented once, with the rationale.
"Amounts stored in cents. Divide by 100." "contract_months is null for monthly subscriptions; treat as 1." The kind of thing the senior analyst who built the table remembers and nobody else does.
You don't need to define everything at once. Start with the metrics that show up in every weekly review and every board deck. For most B2B SaaS:
Committed recurring revenue from active subscriptions. The most-asked metric and the one that drifts the most.
Logo or revenue churn? Trailing 12 months or month-over-month? Cancellations or also paused? Pin it down.
Current revenue from a cohort vs. starting revenue from the same cohort 12 months ago. Watch the cohort definition. It's where most teams disagree.
What stage counts? What close-date window? What probability threshold? The biggest gap between sales' definition and finance's definition.
Last 7 days? 28? Daily-active or weekly-active? Counting unique accounts or unique users? Specify it once.
Most teams write metric definitions once. Two months later, the company expands into a new currency and "MRR" needs a currency-conversion rule. Whoever knew the old definition updates a Google Doc, sends a Slack message, and the AI tools never hear about it.
The way to prevent that is making the definition a single source of truth that AI reads every time, not a document that gets pasted into prompts. When you update MRR's formula in Contextary, every Claude conversation, every Cursor query, every dashboard built tomorrow uses the new version automatically. There's no second place to update.
Pair that with an activity feed (who changed what, when) and you have a metric system that scales beyond one analyst's memory. See how to document your warehouse for Claude for the broader playbook.
Metric definitions are layer four of the four-layer context system. Here's the full playbook.
Bad metric definitions are one of the five common ways AI gets your numbers wrong.
How metric definitions actually reach Claude reliably, across every conversation.
Set up the warehouse connection that powers consistent metrics. Same shape for BigQuery, Postgres, Redshift.
Stop the boardroom argument about which AI is right. Free to start.