Two options. For simple formulas, write the formula into the system prompt and the model executes it on the inputs. For more complex math, define a PHP function (e.g. compute_roi($inputs, $benchmarks)) and expose it via tool use, so the model passes the inputs in and gets a deterministic number out. Tool use is the safer path for anything that ends up in a proposal.

From a custom table or set of ACF fields you control. Many teams seed the table with public analyst data, then refine with their own customer outcomes once the case-study count is high enough. Updates take effect on the next conversation. No redeploy, no calculator-page edit, no caching surprise.

Yes. The system prompt can avoid quoting list price for free-mail addresses or under a threshold of inputs (e.g. under 50 seats), and instead route the conversation to a quick call. Display conditions can also scope the bot so it only appears for visitors who have already passed certain filters.

Validation lives in the formula function. If headcount is negative or current cost is zero, return a clean 'I cannot compute on those inputs' message and ask the visitor to clarify. The bot then mirrors that politely. This protects the calculator from being weaponised by competitors testing edge cases.

Yes. Pricing tiers and product bundles in wp_postmeta become structured variables. The bot can quote the right tier based on headcount or feature requirements, run the ROI math, and reply with both tiers if the visitor is borderline. Multibot lets you split into product-line-specific calculators if pricing logic diverges sharply.

A chat layer that wraps a static calculator still depends on the visitor knowing which fields matter. SleekAI lets the model pick which inputs to ask for, based on the visitor's context and the formula's actual sensitivity. Three smart questions land better than twelve mediocre ones, and completion rates often double or triple.

Yes. The lead-capture hook pushes the inputs, computed result, formula version, page URL, and transcript to your CRM. The SDR opens a record that already includes 'Acme, 200 seats, current cost $480k, computed ROI 64 percent' and writes a relevant first email instead of guessing from a form submission.

Tool use can call any PHP function, so an NPV model with discount rates, multi-year cohorts, and salvage values is doable. The constraint is what your team can maintain and explain in a sales conversation. Most teams find that a clean 3-input, 1-year ROI plus a 2-input payback figure lands better than an opaque 7-input NPV that buyers cannot verify.