"nika: v1\nworkflow:\n  id: image-fx-batch\n  description: \"Folder of PNG files → deterministic art (grayscale · dither · pixelate) · offline batch\"\n\nconst:\n  # Two sample photos ship with the repo. Point this at your own folder and\n  # move `permits.fs.read` with it — a const is baked in, never caller-supplied,\n  # so the two lines stay in step by editing, not by magic.\n  photos: \"examples/fixtures/photos\"\n\npermits:\n  exec: false\n  tools: [\"nika:glob\", \"nika:image_fx\", \"nika:jq\"]\n  fs:\n    # ONE entry that has to cover TWO different reads, and this is the trap:\n    #   · `nika:glob` gates its WALK ROOT — the directory itself\n    #   · `nika:image_fx` gates each MATCHED FILE underneath it\n    # Measured against 0.106.0: granting only `…/photos` passes `check` with\n    # zero hints and then dies at run — NIKA-SEC-004 on the first photo.\n    # Granting only `…/photos/*.png` is worse: `check` calls the entry drift\n    # (it matches no literal the body names) and the glob is refused at run.\n    # `**` covers the directory AND every descendant, so one entry is honest\n    # here; `[\"…/photos\", \"…/photos/*.png\"]` is the two-entry equivalent.\n    read: [\"examples/fixtures/photos/**\"]\n    # The renders land FLAT in one directory, so `*` is enough: it matches a\n    # single path segment and never crosses `/`, which means a photo whose\n    # name contained a slash could not steer a write into a subtree.\n    write: [\"out/darkroom/*\"]\n\ntasks:\n  # The folder is the work list — no hand-maintained array to drift.\n  shots:\n    invoke:\n      tool: \"nika:glob\"\n      args: { pattern: \"\u0024{{ const.photos }}/*.png\" }\n\n  # Derive {src, out} pairs · jq does the string work, natively.\n  jobs:\n    with:\n      shots: \u0024{{ tasks.shots.output }}\n    invoke:\n      tool: \"nika:jq\"\n      args:\n        input: \"\u0024{{ with.shots }}\"\n        expression: 'map({ src: ., out: (\"out/darkroom/\" + (split(\"/\") | last)) })'\n\n  # One deterministic darkroom pass per photo · the ops run IN ORDER.\n  stylize:\n    with:\n      jobs: \u0024{{ tasks.jobs.output }}\n    for_each: \u0024{{ with.jobs }}\n    max_parallel: 4\n    invoke:\n      tool: \"nika:image_fx\"\n      args:\n        input: \"\u0024{{ item.src }}\"\n        out: \"\u0024{{ item.out }}\"\n        seed: 0                       # explicit · the render is a function of (bytes · ops · seed)\n        ops:\n          - grayscale: {}\n          - dither: { mode: bayer4 }\n          - pixelate: { block: 4 }\n\noutputs:\n  rendered:\n    # an empty folder skips the fan-out (its output is null) — the guard keeps\n    # the typed contract honest on the very first exploratory run\n    value: \"\u0024{{ tasks.stylize.output != null ? tasks.stylize.output : [] }}\"\n    description: \"The stylized artifact receipts · one per input photo · path + sha256\"\n"

{"a":{"graph_format":2,"workflow":"image-fx-batch","nodes":[{"id":"shots","verb":"invoke","tool":"nika:glob","permits":["tool: nika:glob"]},{"id":"jobs","verb":"invoke","tool":"nika:jq","permits":["tool: nika:jq"]},{"id":"stylize","verb":"invoke","tool":"nika:image_fx","fan_out":{"kind":"expression"},"permits":["tool: nika:image_fx"]}],"edges":[{"from":"jobs","to":"stylize","kind":"value"},{"from":"shots","to":"jobs","kind":"value"}]},"engine":"0.106.1"}

showcase · tier 1 · content

Image FX batch

glob lists the folder, for_each styles every photo through the same deterministic ops chain: no model, pure pixels.

The preset lives in git. Re-run in a year: byte-identical art, zero clicks. · conformance-gated in nika-spec ↗ · re-proven at every push

3tasksthe plan falls out of the bindings
3wavesparallel by construction
1verbs exercisedinvoke
T1the tiercontent

The whole file

3 tasks · 3 waves

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

image-fx-batch.nika.yamlsource

1nika: v12workflow:3  id: image-fx-batch4  description: "Folder of PNG files → deterministic art (grayscale · dither · pixelate) · offline batch"56const:7  # Two sample photos ship with the repo. Point this at your own folder and8  # move `permits.fs.read` with it — a const is baked in, never caller-supplied,9  # so the two lines stay in step by editing, not by magic.10  photos: "examples/fixtures/photos"1112⛨permits:13  ⛨exec: false14  ⛨tools: ["nika:glob", "nika:image_fx", "nika:jq"]15  ⛨fs:16    # ONE entry that has to cover TWO different reads, and this is the trap:17    #   · `nika:glob` gates its WALK ROOT — the directory itself18    #   · `nika:image_fx` gates each MATCHED FILE underneath it19    # Measured against 0.106.0: granting only `…/photos` passes `check` with20    # zero hints and then dies at run — NIKA-SEC-004 on the first photo.21    # Granting only `…/photos/*.png` is worse: `check` calls the entry drift22    # (it matches no literal the body names) and the glob is refused at run.23    # `**` covers the directory AND every descendant, so one entry is honest24    # here; `["…/photos", "…/photos/*.png"]` is the two-entry equivalent.25    ⛨read: ["examples/fixtures/photos/**"]26    # The renders land FLAT in one directory, so `*` is enough: it matches a27    # single path segment and never crosses `/`, which means a photo whose28    # name contained a slash could not steer a write into a subtree.29    ⛨write: ["out/darkroom/*"]3031tasks:32  # The folder is the work list — no hand-maintained array to drift.33  shots:34    ◆invoke:35      tool: "nika:glob"36      args: { pattern: "${{ const.photos }}/*.png" }3738  # Derive {src, out} pairs · jq does the string work, natively.39  jobs:40    with:41      shots: ${{ tasks.shots.output }}42    ◆invoke:43      tool: "nika:jq"44      args:45        input: "${{ with.shots }}"46        expression: 'map({ src: ., out: ("out/darkroom/" + (split("/") | last)) })'4748  # One deterministic darkroom pass per photo · the ops run IN ORDER.49  stylize:50    with:51      jobs: ${{ tasks.jobs.output }}52    for_each: ${{ with.jobs }}53    max_parallel: 454    ◆invoke:55      tool: "nika:image_fx"56      args:57        input: "${{ item.src }}"58        out: "${{ item.out }}"59        seed: 0                       # explicit · the render is a function of (bytes · ops · seed)60        ops:61          - grayscale: {}62          - dither: { mode: bayer4 }63          - pixelate: { block: 4 }6465outputs:66  rendered:67    # an empty folder skips the fan-out (its output is null) — the guard keeps68    # the typed contract honest on the very first exploratory run69    value: "${{ tasks.stylize.output != null ? tasks.stylize.output : [] }}"70    description: "The stylized artifact receipts · one per input photo · path + sha256"71

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

2 declared edges · 3 waves · the plan falls out of the bindings

try itopen in the playground guidethe walkthrough · docs verbinvoke toolnika:glob toolnika:jq toolnika:image_fx