The task is a retrieval task: retrieve contribution_rate for the supplied payroll month. I need to:
1. List documents to find the case inputs.
2. Read the document(s) to get the payroll month.
3. Look up reference rows (probably need to determine which half of the year the month falls in).
4. Return the R8 JSON answer with decision: "retrieve", field: "contribution_rate", value (decimal string, not percentage), and clauses citing R1 and R3.

Let me start by listing documents.

One document. Let me read it.

The payroll month is 2026-12. December is in the second half of the year. Let me look up the second-half reference rows.

The second-half reference row covers 2026-07 through 2026-12 (months listed: ["2026-07", "2026-12"] — likely the period boundary). The payroll month 2026-12 falls within this row. The contribution_rate is "0.05".

For a retrieval task, I return:
- decision: "retrieve"
- field: "contribution_rate"
- value: "0.05" (decimal string, not percentage)
- clauses: cite R1 (selecting rule) and R3 (source rule), not R8.

Value should be a decimal string: "0.05".

The task is a retrieval task: retrieve `contribution_rate` for a supplied payroll month. I need to find the case inputs via list_documents and read_document, then use lookup_reference to get the reference row for the payroll month.

Let me start by listing documents and looking up references. Actually, I need to know the payroll month first, which comes from the documents. Let me list documents first, then read them. The lookup_reference calls (first-half, second-half) don't depend on the documents... but I don't know which half to look up until I know the month. However, I could call both lookups in parallel with list_documents. But the instructions say to make independent calls in the same block. list_documents and both lookup_reference calls are independent. But maybe better to first list documents, read them, then look up the right half. Actually calling both halves upfront is fine and independent.

Let me do: list_documents + lookup_reference(first-half) + lookup_reference(second-half) in one block.

Now read the payroll document to get the payroll month.

The payroll month is 2026-12, which falls in the second-half row: rate "0.05", cap "4000.00". The retrieval field is `contribution_rate`, so the value is "0.05" (decimal string, not percentage). Cite R1 (selecting rule) and R3 (source rule for contribution_rate).

The task is a retrieval task: retrieve contribution_rate for the supplied payroll month. I need to list documents to find the payroll month, read the document, then look up the reference (first-half or second-half depending on month), and return the contribution_rate.

Let me start by listing documents.

The payroll month is 2026-12, which is in the second half of the year. I need to look up the second-half reference to get the contribution_rate.

The payroll month is 2026-12, which is covered by the second-half reference row (months 2026-07 through 2026-12). The contribution_rate is "0.05".

Return the R8 JSON: decision "retrieve", field "contribution_rate", value "0.05", clauses citing R1 and R3 (not R8).