"nika: v1\nworkflow:\n  id: invoice-chaser\n  description: \"Ledger CSV → overdue filter → drafted reminders → human gate → drafts file\"\n\nmodel: ollama/qwen3.5:4b   # local · zero key · swap for groq/llama-3.3-70b (drafting is a fast-model job)\n\nconst:\n  ledger_csv: \"examples/fixtures/invoices.csv\"\npermits:\n  tools: [\"nika:convert\", \"nika:jq\", \"nika:prompt\", \"nika:read\", \"nika:write\"]\n  fs:\n    # Two files, both spelled out — `const.ledger_csv` in, the drafts file\n    # out. A const is baked in and a run cannot move it, so the boundary is\n    # exact: no glob, and nothing else on disk is reachable either way.\n    read: [\"examples/fixtures/invoices.csv\"]\n    write: [\"out/reminders-to-send.md\"]\n\ntasks:\n  ledger:\n    invoke:\n      tool: \"nika:read\"\n      args: { path: \"\u0024{{ const.ledger_csv }}\" }\n\n  rows:\n    with:\n      csv: \u0024{{ tasks.ledger.output }}\n    invoke:\n      tool: \"nika:convert\"\n      args:\n        input: \"\u0024{{ with.csv }}\"\n        from: csv\n        to: json\n        has_header: true\n\n  overdue:\n    with:\n      rows: \u0024{{ tasks.rows.output }}\n    invoke:\n      tool: \"nika:jq\"\n      args:\n        input: \"\u0024{{ with.rows }}\"\n        expression: 'map(select(.status == \"overdue\"))'\n\n  drafts:\n    with:\n      overdue: \u0024{{ tasks.overdue.output }}\n    when: \u0024{{ size(with.overdue) > 0 }}\n    infer:\n      max_tokens: 900       # a ceiling makes the cost report a number, not UNBOUNDED\n      prompt: |\n        Draft one short, polite payment reminder per overdue invoice ·\n        \u0024{{ with.overdue }}\n        Markdown · one section per client · firm but warm.\n\n  approve:\n    with:\n      drafts: \u0024{{ tasks.drafts.output }}\n    when: \u0024{{ with.drafts != null }}   # nothing drafted · nothing to approve\n    invoke:\n      tool: \"nika:prompt\"\n      args:\n        message: \"Save the reminder drafts for sending?\"\n        default: false\n\n  save:\n    with:\n      drafts: \u0024{{ tasks.drafts.output }}\n      approved: \u0024{{ tasks.approve.output }}\n    when: \u0024{{ with.drafts != null && with.approved == true }}   # zero overdue → drafts skipped (null) · don't write nothing\n    invoke:\n      tool: \"nika:write\"\n      args:\n        path: out/reminders-to-send.md\n        create_dirs: true\n        content: \"\u0024{{ with.drafts }}\"\n\noutputs:\n  overdue:\n    value: \u0024{{ tasks.overdue.output }}\n    description: \"The overdue rows the reminders were drafted for\"\n"

{"a":{"graph_format":2,"workflow":"invoice-chaser","nodes":[{"id":"ledger","verb":"invoke","tool":"nika:read","permits":["tool: nika:read"]},{"id":"rows","verb":"invoke","tool":"nika:convert","permits":["tool: nika:convert"]},{"id":"overdue","verb":"invoke","tool":"nika:jq","permits":["tool: nika:jq"]},{"id":"drafts","verb":"infer","model":"ollama/qwen3.5:4b","when":"\u0024{{ size(with.overdue) > 0 }}","permits":[]},{"id":"approve","verb":"invoke","tool":"nika:prompt","when":"\u0024{{ with.drafts != null }}","permits":["tool: nika:prompt"]},{"id":"save","verb":"invoke","tool":"nika:write","when":"\u0024{{ with.drafts != null && with.approved == true }}","permits":["fs.write: out/reminders-to-send.md","tool: nika:write"]}],"edges":[{"from":"approve","to":"save","kind":"value"},{"from":"drafts","to":"approve","kind":"value"},{"from":"drafts","to":"save","kind":"value"},{"from":"ledger","to":"rows","kind":"value"},{"from":"overdue","to":"drafts","kind":"value"},{"from":"rows","to":"overdue","kind":"value"}]},"engine":"0.106.1"}

showcase · tier 2 · business

Invoice chaser

jq filters the overdue rows out of the CSV, reminders get drafted, and a human gate sits before anything is saved.

Friday’s awkward chore shrinks to reading the drafts and typing yes. · conformance-gated in nika-spec ↗ · re-proven at every push

6tasksthe plan falls out of the bindings
6wavesparallel by construction
2verbs exercisedinvoke · infer
T2the tierbusiness

The whole file

6 tasks · 6 waves

The plan falls out of the bindings, nothing is scheduled by hand.

invoice-chaser.nika.yamlsource

1nika: v12workflow:3  id: invoice-chaser4  description: "Ledger CSV → overdue filter → drafted reminders → human gate → drafts file"56model: ollama/qwen3.5:4b   # local · zero key · swap for groq/llama-3.3-70b (drafting is a fast-model job)78const:9  ledger_csv: "examples/fixtures/invoices.csv"10⛨permits:11  ⛨tools: ["nika:convert", "nika:jq", "nika:prompt", "nika:read", "nika:write"]12  ⛨fs:13    # Two files, both spelled out — `const.ledger_csv` in, the drafts file14    # out. A const is baked in and a run cannot move it, so the boundary is15    # exact: no glob, and nothing else on disk is reachable either way.16    ⛨read: ["examples/fixtures/invoices.csv"]17    ⛨write: ["out/reminders-to-send.md"]1819tasks:20  ledger:21    ◆invoke:22      tool: "nika:read"23      args: { path: "${{ const.ledger_csv }}" }2425  rows:26    with:27      csv: ${{ tasks.ledger.output }}28    ◆invoke:29      tool: "nika:convert"30      args:31        input: "${{ with.csv }}"32        from: csv33        to: json34        has_header: true3536  overdue:37    with:38      rows: ${{ tasks.rows.output }}39    ◆invoke:40      tool: "nika:jq"41      args:42        input: "${{ with.rows }}"43        expression: 'map(select(.status == "overdue"))'4445  drafts:46    with:47      overdue: ${{ tasks.overdue.output }}48    when: ${{ size(with.overdue) > 0 }}49    ◇infer:50      max_tokens: 900       # a ceiling makes the cost report a number, not UNBOUNDED51      prompt: |52        Draft one short, polite payment reminder per overdue invoice ·53        ${{ with.overdue }}54        Markdown · one section per client · firm but warm.5556  approve:57    with:58      drafts: ${{ tasks.drafts.output }}59    when: ${{ with.drafts != null }}   # nothing drafted · nothing to approve60    ◆invoke:61      tool: "nika:prompt"62      args:63        message: "Save the reminder drafts for sending?"64        default: false6566  save:67    with:68      drafts: ${{ tasks.drafts.output }}69      approved: ${{ tasks.approve.output }}70    when: ${{ with.drafts != null && with.approved == true }}   # zero overdue → drafts skipped (null) · don't write nothing71    ◆invoke:72      tool: "nika:write"73      args:74        path: out/reminders-to-send.md75        create_dirs: true76        content: "${{ with.drafts }}"7778outputs:79  overdue:80    value: ${{ tasks.overdue.output }}81    description: "The overdue rows the reminders were drafted for"82

nika inspect · engine 0.106.1 · vendored graph, never re-derived

6 declared edges · 6 waves · the plan falls out of the bindings

try itopen in the playground guidethe walkthrough · docs verbinvoke verbinfer toolnika:read toolnika:convert toolnika:jq toolnika:prompt toolnika:write