Tracing, observability, and cost monitoring
By the end of today you can trace a single AI request through every model call, tool and retrieval, and answer why one user's request cost forty times the median.
YesterdayOn Day 53 you learned logs, metrics and traces answer different questions. Every word of that applies here, with cost added as a first-class signal.
TomorrowTomorrow, the security failures that this instrumentation is how you detect.
Why this matters
AI systems fail quietly. Nothing errors, latency looks fine, and the answers are subtly wrong or the bill is four times last month's. Only tracing shows you what actually happened.
- Tracing AI requests
- Observing AI systems
- Cost as a signal
- Monitoring quality
Learn it
75 minCopy this into Claude or ChatGPT. It quizzes you before it explains anything, which is deliberate. The resources under it are how you check what it told you.
Today's Master Prompt
Free · sign inA prompt written for this day alone: your level, the exact scope, what to leave out, and an instruction to quiz you before it explains anything. Paste it into Claude or ChatGPT and it teaches you today's material.
Check it against something that is not a model
An assistant can be fluent and wrong, and on a topic you met today you will not catch it. These cover the same ground and were made by people who do this for a living, so they are what you hold the explanation up against. They are other people's work and we only link to them, so judge them for yourself.
3 hand-picked resources
Free · sign inVideos, official docs and articles covering the same ground, each opened and annotated by hand. They are what you check the assistant against on a day you cannot yet catch it being wrong.
Build it
55 minAdd tracing to your agent so one request produces a tree with every model call, tool call and retrieval, each carrying tokens, latency and cost. Run twenty varied requests and plot the cost distribution. Find your most expensive request and explain from the trace alone why it cost what it did.
Recall it
20 minAnswer out loud, reveal, then mark honestly whether you had it. That score is the only thing on this page you do not get to choose.
5 recall questions
Free · sign inQuestions you answer from memory, then grade yourself against the real answer. The score is carried into the mastery rating below it, so an honest miss cannot quietly become a tick.
Rate it
Completion and mastery are tracked separately. Be honest, because an inflated rating only means the concept resurfaces sooner.
Mastery tracking
Free · sign inRate yourself against five named criteria per concept. Completion and mastery are tracked separately, and anything you rate shakily comes back automatically on a spaced schedule.
Recap
- 01Failure here is in content, so status codes and error rates never fire
- 02A trace is the only view of the whole tree one request becomes
- 03Watch the cost distribution; the average hides the runaway tail
- 04Version prompts and models, or a regression cannot be attributed
Your progress
Free · sign inMark days complete, pick up where you left off across devices, and watch completion and mastery diverge. Free, and the account exists only so ninety days of work cannot vanish with a cleared browser.