# What is a deep trace? > A deep trace opens one conversation down to the prompt. That's a scarce forensic unit, so aim it at the top of the cost distribution, not at alerts. URL: https://getculpa.com/what-is-a-deep-trace Last reviewed: 2026-08-02 ## Answer A deep trace opens one conversation all the way down to the prompt, so you can read what actually happened rather than what a chart summarised. Culpa, a local-first LLM cost, margin, and forecast ledger, meters these separately from ordinary tracking because they're the expensive question, and an entry plan carries a few hundred a month. ## Why this happens Two different jobs sit inside cost forensics, and they price differently for good reason. Recording every call is cheap and continuous, so it's metered in millions. Opening one conversation to the prompt is a deliberate investigation, so it's metered in hundreds. That scarcity is the useful part, because it forces the question nobody asks of an unlimited tool: which conversation is worth reading. Aimed at the top of the cost distribution a few hundred traces cover most of the money. Aimed at whatever alerted most recently they cover noise. ## What this usually looks like - Traces get opened on whatever alerted, rather than on whatever cost the most. - Nobody has ranked conversations by spend before deciding which to open. - The allowance runs out mid-month and the expensive conversations were never read. - A single investigation opens dozens of traces to answer one question. ## Common mistakes - Spending traces on alerts instead of on cost rank. Why it hurts: An alert fires on a threshold, not on size, so the loudest call is rarely the dearest one. Do instead: Sort by spend first and open traces from the top down. - Opening a trace before checking the aggregate view. Why it hurts: Most questions resolve at the feature or model level for no forensic cost at all. Do instead: Answer what you can from the cheap view, then spend a trace on what's left. - Treating the allowance as a monthly target to use up. Why it hurts: Unused capacity isn't waste, and a month with few investigations is usually a good month. Do instead: Track how much of your spend your traces covered, not how many you ran. ## Self-check - Rank last month's conversations by cost and look at the top twenty. - Work out what share of total spend those twenty carry. It's usually large. - Count how many traces you opened, and how many were in that top group. - Divide traces spent on the top decile by traces spent overall. That ratio is your aim. - Check whether your allowance ran out before the expensive conversations were read. ## Where a few hundred traces should point (illustrative) A product holding 180,000 conversations in a month against an entry allowance of 250 deep traces. The cost distribution below is modelled on the long tail these workloads usually follow. 250 traces against 180,000 conversations is 0.14% of them Spent at random, 250 traces read 0.14% of the spend, which is nothing Ranked by cost, the top 0.14% of conversations often carry a double-digit share of the bill So the same 250 traces move from covering a rounding error to covering the expensive tail The allowance never changed. Only the aim did A scarce forensic budget is a targeting problem, not a capacity problem. Two hundred and fifty traces are plenty if they land on the top of the distribution and useless if they land anywhere else. ## Cost figures Every figure carries its confidence and its source. No figure on this site is provider-reported. - 250 to 1,200 — deep traces carried per month across the three published tiers [estimated] Source: Culpa's published plan table, read 2026-08-02, and the same figures in the shipped plan configuration. A range because it spans the entry and top tiers. - 0.14% — modelled share of a month's conversations an entry allowance can open [calculated] Source: 250 deep traces divided by 180,000 modelled conversations, from the teardown arithmetic. ## FAQ Q: What does a deep trace show? A: One conversation opened down to the prompt, so you can read the actual exchange that spent the money rather than an aggregate of it. That's the difference between knowing a feature is expensive and knowing why. Q: How many deep traces do I need a month? A: Fewer than most teams expect, if they're aimed well. The published tiers carry 250, 500 and 1,200 a month, and a few hundred aimed at the top of the cost distribution covers most of the spend worth investigating. Q: Why meter traces separately from tracked calls? A: Because they're different jobs at different scales. Recording every call is continuous and cheap, so it's counted in millions. Opening one conversation to the prompt is a deliberate investigation, so it's counted in hundreds. ## Sources - Anthropic pricing: https://platform.claude.com/docs/en/docs/about-claude/pricing Run the free Cost Leak Scan: https://app.getculpa.com/scan?source=pseo&slug=what-is-a-deep-trace&cluster=metric Machine-readable index of every guide: https://getculpa.com/api/pages Human-readable index of every guide: https://getculpa.com/guides Site overview: https://app.getculpa.com/llms.txt Privacy: Culpa runs on your infrastructure. Your prompts and responses never leave it. Culpa counts calls to run your plan, and it fails open, so if it ever breaks your app keeps running.