AI Sub Plans: Emergency Plans a Substitute Can Run Cold

What are AI sub plans?

AI sub plans are substitute-teacher plans drafted with an AI tool from a prompt that encodes what a sub day actually is: a stranger running your class without your logins, your subject knowledge, or your authority. You supply those constraints and the class's current position; the AI writes the plan around them.

That definition carries a warning inside it. AI is genuinely good at sub plans — they're structured, wordy, and formulaic in exactly the way language models like. But ask for "a sub plan for my chemistry class" with no constraints and you'll get a lesson plan wearing a sub plan's name tag: it will assume a projector, a working knowledge of stoichiometry, and a teacher the students respect. None of those will be in the room. This guide is about writing the prompt so the plan survives contact with whoever actually shows up. (For planning the lessons you deliver yourself, start with our pillar guide to AI lesson planning — this article covers the one kind of plan you write for someone else to teach.)

Why a sub plan is a different genre

A lesson plan is notes to yourself. You can write "discuss results, address misconceptions" because you know which misconceptions third period harbors and how to draw them out. A sub plan is a set of instructions to a stranger, and it fails wherever it silently assumes the stranger is you.

And "stranger" is optimistic. In a May 2022 NCES School Pulse Panel survey of 846 public schools, 77 percent reported that finding substitutes had gotten harder than before the pandemic, and 99 percent said they couldn't always find one when needed. When no sub materializes, the same survey found, the plan gets handed to an administrator (74 percent of schools), non-teaching staff (71 percent), or a colleague burning their prep period (68 percent). Your plan might be run by an assistant principal between discipline meetings. Write for the least-prepared plausible reader, because some days that's who gets the folder.

Three assumptions have to come out of the plan, and each one changes how you prompt:

No improvisation. You adjust mid-lesson constantly — stretching an activity that's landing, cutting one that isn't, filling the awkward six minutes before the bell. A sub can't, so the plan has to be self-executing: every minute assigned, every transition scripted, and a labeled overflow task for the time the plan doesn't fill. Dead air is the sub-day failure mode; a class with nothing to do writes the referral stories.

No tech. Assume the substitute cannot log into your LMS, your gradebook, the projector cart, or the laptop drawer — because in most buildings, day-to-day subs genuinely can't, and the ones who could shouldn't be locked out of the plan when the Wi-Fi hiccups. If the day depends on a video or a Google Classroom assignment, the day depends on a login you won't be there to type. Paper survives everything.

No behavioral capital. Your classroom management is mostly invisible — a look, a name, standing near the corner desk. The sub inherits none of it. What transfers is structure: entry directions already on the board, work that's collected (students behave differently when something's turned in), and expectations written in the sub's own voice so they read as the adult in the room, not as a messenger citing an absent authority.

The emergency folder and the 5:40 a.m. plan

Sub plans get written in two situations so different they need different prompts.

The emergency folder is built in advance — many schools ask for two or three generic days on file in the front office by fall. The defining constraint is that you don't know when it will be used, so the plan can't reference "yesterday," the current unit, or a season. The way to make a generic day worth teaching is to build it on skills instead of content: in chemistry, reading a data table, interpreting a graph, writing a claim from evidence. Those are legitimate in September and legitimate in April.

Emergency-folder prompt: "Build one generic full-day sub plan for 10th-grade chemistry that will make sense in any month of the year — no references to dates, seasons, or a current unit, and absolutely no lab work; the substitute is not a science teacher and everything must run on paper. Structure: a 5-minute entry task the sub copies onto the board; a 25-minute reading (write it, ~700 words) about how a real industrial process uses chemistry, with 8 questions that each require citing a line from the text; a 15-minute exercise reading the data table I'll paste below; a 10-minute written reflection that gets turned in. Nothing the sub has to grade or explain — but put an answer key for the questions and the data-table exercise on a separate final page, labeled for the returning teacher. Write all student-facing directions in the substitute's voice, and end with a half-page note to the substitute: what to collect, where to leave it, and what to do with early finishers."

Run that prompt three times with different reading topics and you have a folder. Then add the one refinement the folder deserves: a leveled version of each reading for your supported sections — a five-minute follow-up request, and the technique is covered in our guide to differentiation with AI.

What changes below 6th grade. The genre holds but the shape shifts, because an elementary sub inherits a whole self-contained day, not periods. Adjust the emergency prompt three ways for, say, a 3rd-grade room: script every transition by name ("When math ends, say: clear your desk and take out your book box"), because routines are the management plan and the sub doesn't know yours; make the anchor activity a read-aloud with a printed text and listening questions — the one thing any adult can run cold; and turn centers, stations, and rotations off in favor of whole-group and independent work, since they run on trained habits that leave the room with you. The info sheet also carries more of the day at this level: specials times, lunch count, duty posts, and the dismissal procedure are where an elementary sub day actually falls apart.

The 5:40 a.m. plan is the other situation: you're sick, it's dark, and the plan has to reflect exactly where your classes are — because unlike the generic folder, this absence lands mid-unit with a pacing guide ticking. This is where AI changes the job most. Writing a precise, three-period sub plan from bed used to take an hour you didn't have; now the hour compresses into one carefully constrained prompt typed on a phone. The next section is that prompt.

A sub-plan prompt that survives a stranger

Here's the pair. The weak version is what most people type on their first sick morning:

Weak: "Write a sub plan for my high school chemistry classes for tomorrow. We're studying stoichiometry."

That returns a confident plan in which the sub reviews mole ratios at the board, circulates to answer questions, plays a video about limiting reactants, and "supervises the scheduled lab if students are prepared." Every clause assumes a chemist with your logins and your keys.

Strong: "Write a sub plan for tomorrow for my three sections of 10th-grade chemistry (periods 1, 2, and 4). The substitute is not a science teacher and cannot log into our LMS or use the projector — everything must run on paper I can email to the front office for printing. Period 4 is co-taught; Ms. Alvarez will be there and runs point on behavior, so address that plan to both adults. We are mid-unit on stoichiometry: students finished mole-to-mole conversions yesterday but have NOT seen mass-to-mass problems, so use only mole-to-mole. Thursday's lab is postponed — no lab, demo, or materials from the lab room under any circumstances. Structure each period: entry directions the sub copies onto the board; a 35-minute practice set of 12 mole-to-mole problems with an answer bank on the last page so students check their own work; a 10-minute exit slip (2 problems, no answer bank) that gets collected; directions in the sub's voice for what to turn in and where. Do not ask the sub to explain any chemistry, grade anything, or manage technology. Add a 10-minute 'if time remains' vocabulary task at the end."

The strong prompt is long because every line is disarming a specific failure:

• "Not a science teacher… do not ask the sub to explain any chemistry" removes the subject-expertise assumption. Note the mechanism that replaces it: an answer bank students check themselves. The feedback loop still happens; it just doesn't route through the adult.
• "Cannot log into our LMS or use the projector — everything on paper" kills the tech dependency, including the version where the AI helpfully suggests "have students submit via Google Classroom."
• "Period 4 is co-taught… address that plan to both adults" handles the co-teaching period. Without it, AI writes for a generic solo adult — and a plan that ignores Ms. Alvarez either sidelines her or leaves the sub unsure who decides anything.
• "Postponed — no lab, demo, or materials from the lab room" is the safety line, stated as an absolute because AI treats soft phrasing ("probably skip the lab") as negotiable. NSTA's position on safety in science instruction holds that anyone responsible for student safety needs appropriate, ongoing safety training; a day-to-day sub hasn't had yours, which is why many district science handbooks ban labs on sub days — check yours.
• "Finished mole-to-mole but have NOT seen mass-to-mass" protects your pacing in both directions. It stops the AI from drafting problems your students can't do yet — its default "stoichiometry practice" reaches for the whole topic — and it makes the day consolidation instead of a movie-day write-off, so the unit test date survives your flu.
• "Exit slip, collected, no answer bank" gives you Monday-morning evidence of what the day actually accomplished — the same logic as any exit ticket, pointed at an absence.
• "In the sub's voice" and the "if time remains" task are the behavioral-capital lines: directions that read as the present adult's, and no dead air.

What AI gets wrong in sub plans

The failure modes here are different from ordinary lesson drafts, because a sub plan's errors don't get caught mid-lesson by a teacher who knows better. Four to check before you hit print:

It invents your textbook. Ask for a chemistry sub plan and some drafts will confidently assign "pages 214–221" and "problems 1–15 on page 223" in a book the AI has never seen — pagination included. It reads as specific, which is exactly what makes it dangerous at 6 a.m. The rule: any reading or problem set the plan references must physically exist in the packet you send. If the AI didn't write it into the document, it isn't real.

It assumes findable materials. "Distribute the periodic-table class set from the supply cabinet" fails twice — the sub doesn't know which cabinet, and the cabinet may be locked. Same for "the graphing calculators," "the goggles bin," anything with a location only you know. The test is blunt: if it isn't stapled to the plan or sitting on your desk with a labeled sticky note, it doesn't exist. Prompt accordingly ("assume the sub can find nothing in the room") and the drafts stop reaching for props.

Your expertise sneaks back in. Even with "the sub is not a science teacher" in the prompt, drafts drift toward "review the answers as a class and clarify misconceptions" — a sentence that requires a chemist. Sweep the draft for verbs the sub can't perform: explain, review, clarify, demonstrate, discuss the reasoning. Each one gets replaced with a mechanism — an answer bank, a worked example printed in the packet, a "circle the problem you're least sure about" flag on the exit slip that routes the confusion to you instead.

The day comes up short. AI timings are optimistic everywhere, but with a sub the error compounds: no teacher presence means work goes faster and off-task drift starts sooner. Overplan by fifteen minutes per period and label the overflow clearly ("IF TIME REMAINS"), so the sub knows it's a buffer and not a requirement.

One more caution that isn't about quality: sub plans are full of student information — seating charts, the kid who leaves early for insulin checks, which two students can't sit together. None of that belongs in a general-purpose chatbot prompt. Keep names and medical details out of the AI conversation and add them to the printed plan afterward; the rules and the reasoning are in our guide to AI and student data privacy.

A worked example: chemistry lab day with a sub

Run the whole method through one bad morning: a 10th-grade chemistry teacher wakes at 5:40 with a fever. Today was supposed to be the limiting-reactant lab — the one the pacing guide budgets for this week because the unit test is in eight days. Three sections, one co-taught. The district curriculum doesn't pause for the flu.

The triage runs in a fixed order. Safety first: the lab is off the table, full stop — not modified, not "demo only." Then pacing: the test date shouldn't move for one absence, so the day needs to do real work, but new content is out because nobody in the room can teach it. That leaves the middle path: consolidate what's been taught, and reschedule the lab into the review day the pacing guide already holds before the test.

From bed, that becomes the strong prompt from the last section, adjusted for today's reality — and about four minutes of review once the draft lands. The four minutes matter more than the prompt does. In a draft like this, expect one or two of the twelve practice problems to quietly assume mass-to-mass conversion — the step these students haven't seen; the AI knows stoichiometry, not where your class stopped. You catch it because you're the only chemist involved, which is the enduring division of labor in every sub plan: AI assembles, you verify against knowledge only you hold.

There's one more shortcut when the lab day already exists as a full plan. If Thursday's lesson is a document, you can paste it in with "rewrite this so a non-scientist substitute can run it on paper" and let the AI do subtraction instead of generation — and if you plan in Planning Partner, the lesson is already sitting there as an editable plan-plus-materials, so the sick-day move is regenerating it under sub constraints rather than describing your own lesson to a chatbot from memory at 5:40. Either way, the sub-day version derives from the real lesson, which keeps the day tethered to the unit instead of parallel to it.

Monday, you collect the exit slips, see that period 2 is shakier on mole ratios than periods 1 and 4, and start the rescheduled lab with a ten-minute repair for one section. The absence cost you a lab slot, not a week.

The part of the folder AI can't write

A finished sub folder is the plan plus the facts around it, and the facts are the part no model can supply: the seating chart, the bell and duty schedule, the fire-drill route, which students are trustworthy runners, the medical notes, your neighbor teacher's room number, where collected work goes. AI can format the shell — ask it for "a one-page sub-folder info sheet template for a high-school science classroom, blanks for me to fill in" and you'll get a decent scaffold — but every blank is yours.

That's a reasonable note to end on, because it's the whole shape of the task. The parts of a sub day that are language — structure, directions, practice sets, the note to the substitute — AI now drafts in minutes, at 5:40 a.m., from a phone. The parts that are knowledge of your room stay yours, and the prompt is where the two meet. Spend your effort there, once, and both kinds of absence — the planned folder and the sick-day scramble — stop being the worst planning job of the year.