Set derived attributes

Use Set derived attribute to store a business label on the invoice (for example business_line = Line-A or MOC), then match that label as a column in your booking-account approval matrix so the right approvers are selected.

You choose how the value is produced under Value source:

• Static value: plain text or expression tokens (e.g. Online, Invoice ${invoice_number})
• LLM derived: a short instruction; Cortena sends the invoice, line items, and booking match to an LLM and stores the returned value plus a reason

To show or edit derived fields on invoice detail and map them into Twinfield or Exact Online descriptions, see Show and edit derived attributes on invoices.

What this feature does

Set derived attribute is a workflow action step. When an invoice reaches that step, Cortena writes one attribute key and value onto the invoice (for example business_line → Line-A).

Common patterns:

• Conditional → Static set: different branches write different fixed values, then join before a booking-account Approval
• LLM set (no Conditional): one step classifies the attribute from the invoice context; optionally route on Success vs Empty / error

On the Approval step, you select which derived attributes participate in matrix matching. Cortena looks for matching columns on the matrix spreadsheet (for example Business Line) and uses the invoice value to narrow which rows, and therefore which approvers, apply.

How it fits the approval matrix

Related deep-dive: Approval matrix.

LLM derived values

When Value source is LLM derived, Cortena does not use a fixed string. It sends your Instruction for the LLM together with the current invoice (header, line items, and booking match) and asks the model for:

• a value for the attribute key (for example MOC or SOC)
• a short reason explaining why

If the model returns a usable value, Cortena stores both. On invoice detail, when the attribute is shown above the line items, hover the field to read the LLM reason (same tooltip style as other invoice explanations).

When the LLM returns nothing or fails

Under When the LLM returns nothing or fails, choose one policy:

Publish validation: If you choose Take the Empty / error path, the workflow editor requires both Success and Empty / error edges before you can publish. Use Empty / error for a human review step, a fallback static set, or a different approval path.

Example instruction

Classify the business line as MOC or SOC based on the supplier and booking accounts. Return only one of those codes as the value.

Keep allowed values exactly aligned with your approval matrix column cells (casing included).

Example: business line before approval

Goal: Invoices for supplier Acme Online should use business line Online; everything else uses Retail. Approvers in the matrix differ by Business Line as well as GL / amount tier.

You can do this with Conditional + Static, or with a single LLM derived step when the rule is harder to express as filters.

Option A: Conditional + Static value

1. Branch with a Conditional

1. Open Workflow → Invoice workflow (or the workflow you manage).
2. Add a Conditional step before your booking-account Approval.
3. Create two branches, for example:
   • If supplier name matches Acme Online (or invoice text / PO pattern you prefer)
   • Else: all other invoices

2. Set the derived attribute on each branch

1. On the If branch, add Set derived attribute (under Actions in ADD STEP).
2. In the right-hand panel:
   • Attribute key: business_line (lowercase letters, digits, underscores; must start with a letter)
   • Value source: Static value
   • Value: Online (plain text is fine)
3. On the Else branch, add another Set derived attribute with the same key business_line and value Retail.
4. Connect both branches so they converge into your Approval step that uses the approval matrix.

Option B: LLM derived (one step)

1. Add a single Set derived attribute before Approval (no Conditional required).
2. Attribute key: business_line
3. Value source: LLM derived
4. Instruction for the LLM: e.g. Classify business line as Online if the supplier is Acme Online (or clearly online retail); otherwise Retail. Return only Online or Retail.
5. Under When the LLM returns nothing or fails, pick Set an empty value and continue, or Take the Empty / error path and connect both outputs (e.g. Empty / error → a review step).
6. Connect Success (or the single outgoing path) into your matrix Approval.

Values must match the sheet. Matrix matching is an exact string match (after normal trimming). If the node writes Online but the sheet cell says ONLINE or has trailing spaces, you may not get the row you expect. Keep casing and spelling consistent for both Static and LLM outputs.

3. Enable the attribute on the Approval node

1. Select the Approval step that uses booking account rules / the matrix.
2. Find Derived attributes for matrix matching.
3. Tick business_line.
4. Add a short description for header analysis, for example: Business line: Online, Retail. That description helps Cortena detect the right spreadsheet column when analysing or refreshing the matrix schema.
5. If the list is empty, add at least one Set derived attribute step in this workflow first. Keys only appear when those steps exist on the canvas.

4. Put the column on the matrix spreadsheet

1. Open the managed approval matrix Google Sheet (see Approval matrix).
2. Ensure there is a column for the attribute, typically Business Line for key business_line.
3. Fill cells with the same values you set in the workflow (Online, Retail). Leave a cell blank when that row should match any business line (wildcard).
4. Save / refresh the matrix schema if you added a new column so Cortena remaps headers.

5. What you see on an invoice

After the set step runs, the invoice detail shows a chip such as business_line: Online near the invoice number (and, if you enable Show on invoice detail / Allow editing, a full field above the line items: see Show and edit derived attributes on invoices). When the approval step runs, Cortena filters matrix rows using that value before resolving approvers.

Configure the Set derived attribute node

1. Go to Workflow and open the editor for the tenant.
2. From ADD STEP → Actions, add Set derived attribute.
3. Set a clear Label (shown in the workflow strip / activity context).
4. Fill Attribute key.
5. Choose Value source:
   • Static value: fill Value (plain text and/or tokens)
   • LLM derived: fill Instruction for the LLM and pick a policy under When the LLM returns nothing or fails
6. Optionally enable Show on invoice detail / Allow editing on invoice detail (see Show and edit derived attributes on invoices).
7. Connect the step on the path where the value should be decided (often before matrix Approval). For LLM + Take the Empty / error path, connect both Success and Empty / error.
8. Save / publish the workflow.

Attribute key rules

• Must match: start with a letter, then only lowercase letters, digits, or underscores
• Examples: business_line, channel, cost_pool
• Invalid keys (spaces, capitals, starting with a digit) cause the step to fail

Static values: plain text or expressions

• Plain text is stored as-is (Line-A, Online).
• Optional dollar-brace expressions (click a variable in the panel to copy), for example ${invoice_number} or ${purchase_order_number}.
• You can also reference an attribute already set earlier: ${derived.business_line}.
• To keep a literal ${…} in the value, prefix the dollar sign with a backslash.
• If the resolved value is empty, the step fails. Avoid expressions that resolve blank for your invoices.

Supported tokens include: invoice_number, purchase_order_number, invoice_supplier_name, invoice_recipient_company, invoice_recipient_name, currency, and derived.<key>.

LLM derived: instruction and empty/error policy

• Write a concrete instruction that names the allowed output values when those feed an approval matrix.
• Cortena includes invoice header, line items, and booking match with the instruction. You do not paste invoice data into the instruction yourself.
• Set an empty value and continue: one outgoing path; empty attribute is stored and the workflow continues.
• Take the Empty / error path: canvas shows Success and Empty / error; both must be connected before publish.

Optional: branch later on a derived attribute

After a value is stored, a later Conditional can use the Derived attribute criterion (attribute key + allowed values) to route again, for example export path vs extra review, without re-deriving the label.

Tips and limitations

• Same workflow only: Matrix checkboxes list keys from Set derived attribute steps on this workflow definition.
• Descriptions matter: Short, concrete descriptions improve column detection when Cortena analyses or refreshes the spreadsheet.
• Empty matrix cell = wildcard for that attribute; missing value on the invoice skips that filter dimension.
• Overwrite: Running another set step with the same key replaces the previous value (and LLM reason meta when the new write is LLM-derived).
• LLM reason on invoice: Hover a shown derived field to see why the LLM chose the value; editing the value on the invoice does not change the stored reason text.
• Static empty fails; LLM empty is configurable: A Static expression that resolves blank fails the step. LLM empty/failure follows your When the LLM returns nothing or fails policy.
• Permissions: Editing the workflow requires workflow management permission for the tenant.
• Prefer one clear key (e.g. business_line) over many overlapping labels unless the matrix truly needs multiple dimensions.

Quick reference