The four layers of AI instructions
You can guide the AI from four different places — an individual output, the template (incl. assembled-PDF guidance), a single source row, or a one-off run. Output rules win over everything else for that specific output; the rest are additive context, in order of specificity.
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You can guide the AI from four different places — an individual output, the template (which now also covers the assembled-PDF guidance that used to live separately on the combiner), a single source row, or a one-off run. Output rules win over everything else for that specific output; the rest are additive context, in order of specificity.
Where Layer 2 (template AI Instructions) lives depends on the template. If the template has any form question field, the AI Instructions textarea appears at the top of the template's Form page in the editor — that's the single editable surface. If the template has no form questions, the textarea lives at the top of the editor's Form tab (which appears automatically when the textarea is non-empty). Same data field underneath; the editor just keeps the Form tab authoritative.
This is the second-most-asked question after "how do I add a field": where do I put my instruction so the AI actually listens? The answer depends on how broadly the instruction applies. Four layers exist because the same template might need a rule that applies to one output, one source PDF inside a stitched-together packet, the whole template, or just a single autofill run for a tricky case.
The four layers at a glance
| # | Layer | Where you edit it | When it applies |
|---|---|---|---|
| 1 | Output | The Prompt box on a zone- or prompt-kind output in the field's Outputs section | One specific output — every time it's extracted |
| 2 | Template | The AI Instructions textarea on the Form tab in the editor | All extracted outputs on this template — covers both the per-output guidance and the assembled-PDF guidance |
| 3 | Per-source | The AI Instructions textarea inside a source tab's chevron popover (multi-source layout) or ⋯ menu (single-source layout) | Quirks of one specific source inside the stitched packet |
| 4 | Special (run-time) | The Special AI Instructions box in the autofill review modal | One run only — never persisted |
What changed: the document-combiner panel used to host its own
AI Instructionstextarea (a fifth layer that described how the assembled PDF should be read). That field was folded into the template'saiInstructionsin May 2026 — write all assembled-PDF guidance into the Layer 2 textarea now.
How they merge
Layer 1 (output) is unique — it's attached to one output and shown to the AI as a Rule: line right next to that output in the prompt. The AI is told explicitly that an output's own Rule wins over any other guidance.
Layers 2 through 4 all fold into a single block of "ground rules" that sit above the output list. Per-source instructions (layer 3) are not deduplicated against the template-level rule — they describe different scopes (one source vs the whole template). Special instructions (layer 4) are appended last but don't outrank the others; the model treats later instructions as additional context, not a higher priority.
Ground rules block (shown to the AI for every output):
layer 2 (template — incl. assembled-PDF guidance)
layer 3 (per-source — one block per source tab with non-empty text)
layer 4 (special — appended last)
Each output also gets:
layer 1 (the output's own Rule — wins for that output)
The takeaway: be specific where you can. An output rule has the most narrowly-targeted effect. A template-wide rule applies to every output whether it's relevant or not.
Where to put what — the decision table
| If the rule applies to… | Put it on… |
|---|---|
| One specific output (one slot in case data) across all docs of this template | Layer 1 — Output |
| All extraction for this template, regardless of which source PDF was used — or describing how the assembled PDF should be read | Layer 2 — Template |
| One source PDF inside a multi-source template | Layer 3 — Per-source |
| One specific autofill run, never to be reused | Layer 4 — Special |
Pushing the rule to the lowest applicable layer keeps the prompt focused. An output rule is shown only when that output is being extracted; a template-level rule is shown for every output. Pile too many template-level rules on and the model gives proportionally less weight to each — you dilute the signal.
Walkthrough: a multi-source permit packet
Your Permit Application template stitches together a county cover sheet, the applicant's W-9, and the contractor's insurance certificate. Each source has its own quirks, plus the permit number on the cover sheet is sometimes printed sideways.
- Open the
Permit Numberfield's Outputs section and open its zone-kind output. In the output's Prompt box write: "Permit numbers always start withPMT-followed by four digits and may be printed rotated 90° on the cover sheet." (Layer 1 — only this output needs this rule.) - Click the W-9 source tab in the document bar above the preview, open the chevron popover, and write in AI instructions for this row: "This page is the vendor's IRS W-9 — extract the tax ID from box 5 only, ignore any handwritten annotations." (Layer 3 — applies only when reading the W-9 source.)
- Click the Form tab in the document bar and write in the template-level AI Instructions textarea: "When the cover sheet and the insurance certificate disagree on the contractor's address, trust the insurance certificate — it's the executed copy." (Layer 2 — applies template-wide, including the assembled PDF.)
- Save. The next autofill run merges these three layers into the prompt automatically.
Common patterns
Lower is better
A rule on an output affects only that output. A template-level rule shows up in the prompt for every output whether it matters or not. When you add a template-level rule, ask: would an output rule do? Almost always, yes.
One-off cases get layer 4
Every template has the rare case where a normally-clean rule needs an exception. Don't pollute the template-level instructions with "but for the Acme Corp submissions, dates are DD/MM/YYYY." Put it in Special AI Instructions in the review modal — it applies to that one run and disappears when the modal closes.
Template ≠ source
Layer 2 (template-level) describes the whole template including the assembled PDF. Layer 3 (per-source) describes one piece of it. If your rule is about how multiple sources interact, that's template-level. If your rule is about one source's quirks, that's per-source. Putting a per-source rule on the template-level dilutes it for all the other sources.
Don't restate the field type
The AI already knows that a date field needs a parseable date and a select field needs one of the allowed options — type constraints are stronger than text instructions. Use the AI Instructions box for things the type system can't enforce: "the date is at the bottom-right of page 3," "use the customer's billing name not their shipping name."
Iterate one rule at a time
If extraction is wrong, change one rule and re-run. Changing two layers at once makes it impossible to tell which change moved the needle.
Troubleshooting
My template-level rule isn't being followed for one specific output. Check the output's own Prompt box in its parent field's Outputs section. An output rule wins over template-level rules for that output. If the output rule contradicts the template rule (even subtly), the output rule applies.
The Special AI Instructions box disappeared after I closed the modal. That's by design — special instructions are run-only. The label says "Applied to this run only." If you want this rule to persist, move it to template-level (or per-source if it only applies to one source).
I added a rule and nothing changed.
The AI is probabilistic — a rule shifts the distribution but doesn't guarantee a specific output. If the rule is critical, also tighten the output's value type or move the field's source to question so a human always fills it.
I'm looking for the combiner-level AI Instructions box. That layer was folded into the template-level AI Instructions textarea (on the Form tab) in May 2026. Anything you used to write there now goes in the template-level box.