Long-Form AI PRD Template for Complex AI Features
TL;DR
Standard PRDs miss what matters most for AI: capability bounds, eval methodology, prompt strategy, model selection, cost-at-scale, and rollback plan. This long-form template covers all of them. Designed for complex AI features — agents, multi-step workflows, RAG-grounded tools, fine-tuned models — where shortcuts in the PRD become incidents in production. Copy-paste ready.
Why Standard PRDs Fail for Complex AI
A traditional PRD describes deterministic behavior. AI features have non-deterministic behavior, and the document needs sections that traditional PRDs don't. If your PRD doesn't name the eval methodology, model choice, prompt strategy, and rollback plan, you're leaving the most consequential AI decisions to whoever happens to ship the code.
Section 1: Problem and user
User, problem, current pain. Same as any PRD.
Section 2: AI capability bounds
What the AI can and can't do reliably. Sets the scope for everything downstream.
Section 3: Success metrics
Model-level + experience-level + business-level. Hierarchy matters.
Section 4: Eval methodology
Golden set, scoring approach, regression strategy. Owner: PM.
Section 5: Architecture
Model choice, retrieval, prompt structure, fallback paths.
Section 6: Cost and latency budget
Per-request and at-scale projections. Both matter.
Section 7: Risk and safety
Hallucination, prompt injection, biased outputs. Mitigations explicit.
Section 8: Rollout and rollback
Phased rollout, kill switches, what triggers rollback.
Section 2: AI Capability Bounds
The capability bounds section is the most under-written and most consequential. State explicitly what the AI is being asked to do, what it's not being asked to do, and what failure modes are acceptable.
In-scope behaviors
"The AI will summarize threads of 100-2000 words in 3 bullet points." Specific. Bounded.
Out-of-scope behaviors
"The AI will not summarize threads under 100 words. The AI will not perform sentiment analysis." Just as important as in-scope.
Acceptable failure modes
"The AI may occasionally miss a key point in long threads. It must not invent participants." Calibrate user expectations.
Capability assumptions
"Assumes the model can follow a structured output format with 99%+ reliability." If this assumption breaks, the feature breaks.
Section 4: Eval Methodology
The eval methodology section is the PM's contract with engineering. It defines how you'll know whether the feature works, what regressions look like, and the bar that must be cleared before launch.
Golden set
Specify size, source, and refresh cadence. 200-500 inputs is typical for a complex feature.
Scoring approach
LLM-as-judge with rubric, human audit on samples, or hybrid. State the choice.
Pass thresholds
"Acceptance rate ≥75%, hallucination rate ≤2%, format adherence ≥99%." Numbers, not adjectives.
Regression strategy
When does eval run? On every prompt change? Daily? Weekly? Who owns the response?
Use This Template With Confidence
The AI PM Masterclass walks through PRD-writing for complex AI features with real examples and instructor reviews of your own PRDs.
Section 7: Risk and Safety
Hallucination risk
What kinds of hallucinations are likely? How are they caught? What's the user-facing handling — refuse, hedge, cite, fall back?
Prompt injection risk
If user input is incorporated into the prompt, what attacks are possible? Sanitization, separation of trust contexts, output validation.
Bias and fairness
Are outputs systematically worse for some user groups? What testing is done? What's the remediation path?
Data leakage
Could the AI surface information it shouldn't? Cross-tenant leakage, PII exposure, training data regurgitation. Mitigations explicit.
Section 8: Rollout and Rollback
Phased rollout plan
Internal → 5% beta → 25% → 100% with eval gates at each stage. Specify the gates.
Kill switch
A single config flag that disables the feature in <2 minutes. Tested before launch.
Rollback triggers
Specific conditions that trigger rollback: error rate, eval drop, user reports. Don't leave it to judgment in the moment.
Communication plan
Who tells whom, on what channel, when something goes wrong. Pre-written templates beat live drafting under stress.