{"agent-loop":"nika: v1\nworkflow:\n  id: agent-loop-template       # SLOT: kebab-case workflow id\n  description: \"plan → budgeted agent → typed result\"   # SLOT\n\nmodel: ollama/qwen3.5:4b           # SLOT: a tool-calling model · local by default\n\nvars:\n  goal:\n    type: string\n    required: true\n    description: \"What the agent must accomplish\"   # SLOT\n\ntasks:\n  plan:\n    infer:\n      prompt: \"Break '${{ vars.goal }}' into at most 4 concrete steps.\"   # SLOT\n      schema:\n        type: object\n        required: [steps]\n        properties:\n          steps: { type: array, items: { type: string } }\n\n  execute:\n    with:\n      steps: ${{ tasks.plan.output.steps }}\n    agent:\n      # The done-contract belongs IN the prompt: the final message must\n      # carry the schema'd shape, so SAY so — a live model that is not\n      # told finishes in prose and fails NIKA-INFER-002 (proven on GPT).\n      system: \"Work the plan step by step. When finished, reply with ONLY your final result as an object carrying a `findings` array (one short string each), then call nika:done.\"   # SLOT\n      prompt: \"Plan · ${{ with.steps }}\"\n      tools:                        # SLOT: the MINIMUM grant for the job\n        - \"nika:read\"\n        - \"nika:done\"\n      max_turns: 15                 # SLOT: the loop bound\n      max_tokens_total: 80000       # SLOT: the spend bound\n      schema:                       # SLOT: the typed final-message contract\n        type: object\n        required: [findings]\n        properties:\n          findings: { type: array, items: { type: string } }\n\n  confirm:\n    with:\n      has_findings: ${{ size(tasks.execute.output.findings) > 0 }}   # the check crosses as ONE boundary expression\n    invoke:\n      tool: \"nika:assert\"\n      args:\n        condition: \"${{ with.has_findings }}\"\n        message: \"Agent returned no findings, do not trust an empty run\"   # SLOT\n\noutputs:\n  findings:\n    value: ${{ tasks.execute.output.findings }}\n    description: \"The agent's typed findings\"   # SLOT\n","api-upload-and-create":"nika: v1\nworkflow:\n  id: api-upload-and-create-template  # SLOT: kebab-case workflow id\n  description: \"upload → create → result\"   # SLOT: one honest sentence\n\nmodel: ollama/qwen3.5:4b            # SLOT: provider/model · local · zero key\n\nvars:\n  api_base: \"https://api.example.com\"     # SLOT: the product API base\n  asset_path: \"./out/assets/asset-1.png\"  # SLOT: the file to upload\n\nsecrets:\n  API_KEY:\n    source: env\n    key: EXAMPLE_API_KEY            # SLOT: the OS env var holding the key\n    egress:\n      - to: \"nika:fetch\"            # the send · default-deny otherwise\n      - to: \"outputs\"               # the return value derives from the authed response\n\ntasks:\n  upload:\n    invoke:\n      tool: \"nika:fetch\"\n      args:\n        url: \"${{ vars.api_base }}/upload\"   # SLOT: the upload endpoint\n        method: POST\n        headers:\n          x-api-key: \"${{ secrets.API_KEY }}\"  # SLOT: the auth header name\n        multipart:\n          - { name: file, path: \"${{ vars.asset_path }}\" }\n          # SLOT: extra text fields · { name: directory, value: \"assets\" }\n        mode: jq\n        jq: \".url\"                  # SLOT: where the response carries the asset URL\n\n  create:\n    with:\n      upload: ${{ tasks.upload.output }}\n    invoke:\n      tool: \"nika:fetch\"\n      args:\n        url: \"${{ vars.api_base }}/create\"   # SLOT: the create endpoint\n        method: POST\n        headers:\n          x-api-key: \"${{ secrets.API_KEY }}\"\n        body:                       # SLOT: the create payload (objects auto-JSON)\n          asset_url: \"${{ with.upload }}\"\n        mode: jq\n        jq: \"{ id: .id, url: .url }\"   # SLOT: the fields downstream needs\n\noutputs:\n  result: ${{ tasks.create.output }}   # SLOT: the callable contract\n","chain":"nika: v1\nworkflow:\n  id: chain-template            # SLOT: kebab-case workflow id\n  description: \"gather → think → persist\"   # SLOT: one honest sentence\n\nmodel: ollama/qwen3.5:4b           # SLOT: provider/model · local · zero key\n\nvars:\n  source: \"./README.md\"             # SLOT: your input — README.md exists in ANY repo, so the\n                                    # skeleton runs green BEFORE you point it at real data\n\ntasks:\n  gather:\n    invoke:                         # SLOT: the fact source · nika:read / nika:fetch / exec\n      tool: \"nika:read\"\n      args: { path: \"${{ vars.source }}\" }\n\n  think:\n    with:\n      gather: ${{ tasks.gather.output }}\n    infer:\n      prompt: |\n        # SLOT: the one model job · interpolate ${{ with.gather }}\n        Summarize · ${{ with.gather }}\n\n  persist:\n    with:\n      think: ${{ tasks.think.output }}\n    invoke:\n      tool: \"nika:write\"\n      args:\n        path: \"./output.md\"         # SLOT: destination\n        content: \"${{ with.think }}\"   # ALWAYS pass content · a write without it writes nothing\n\noutputs:\n  result: ${{ tasks.think.output }}  # SLOT: the callable contract\n","docker-report":"nika: v1\nworkflow:\n  id: docker-report-template    # SLOT: kebab-case workflow id\n  description: \"read the daemon's state · explain it · keep the report\"   # SLOT\n\nmodel: ollama/qwen3.5:4b            # SLOT: local-first · mock/echo for offline rehearsal\n\npermits:\n  exec:\n    - \"docker\"                      # SLOT: the ONE program the reads may launch\n  tools:\n    - \"nika:write\"\n  fs:\n    write:\n      - \"./docker-health.md\"        # SLOT: where the report lands (must match `keep`)\n\ntasks:\n  # The reads run IN PARALLEL (no edges between them) — the\n  # scheduler proves it from the DAG, nobody orders it.\n  ps:\n    exec:\n      # SLOT: argv ARRAY form — one program, exactly these arguments\n      command: [\"docker\", \"ps\", \"--all\", \"--format\", \"{{.Names}}\\t{{.Status}}\\t{{.Image}}\"]\n\n  df:\n    exec:\n      command: [\"docker\", \"system\", \"df\"]   # SLOT: the second read (drop the task if one suffices)\n\n  diagnose:\n    with:\n      ps: ${{ tasks.ps.output }}\n      df: ${{ tasks.df.output }}\n    infer:\n      # SLOT: what should the model DO with the readings?\n      prompt: |\n        You are reading a Docker host's state. Containers (name·status·image):\n        ${{ with.ps }}\n\n        Disk usage:\n        ${{ with.df }}\n\n        Write a short health report: what is running, what exited, what\n        looks unhealthy (restart loops · old exits), and whether disk\n        usage needs attention. Plain prose, no preamble.\n      max_tokens: 600               # SLOT: the spend ceiling for this call\n\n  keep:\n    with:\n      diagnose: ${{ tasks.diagnose.output }}\n    invoke:\n      tool: \"nika:write\"\n      args:\n        path: \"./docker-health.md\"  # SLOT: same path as permits.fs.write\n        content: \"${{ with.diagnose }}\"\n\noutputs:\n  report: ${{ tasks.keep.output }}\n","etl-state":"nika: v1\nworkflow:\n  id: etl-state-template        # SLOT: kebab-case workflow id\n  description: \"read state · fetch fresh · diff · process the delta · save state\"   # SLOT\n\nvars:\n  source_url: \"https://api.example.com/v1/records\"   # SLOT: the data source\n  state_path: \"./state/etl-state.json\"               # SLOT: the cursor file\n\ntasks:\n  # First run · no state file yet · recover to an empty list.\n  empty:\n    invoke:\n      tool: \"nika:jq\"\n      args: { input: [], expression: \".\" }\n\n  previous:\n    invoke:\n      tool: \"nika:read\"\n      args: { path: \"${{ vars.state_path }}\" }\n    on_error:\n      on_codes: [NIKA-BUILTIN-READ-001]   # not-found ONLY · a permission error still fails loudly\n      recover: ${{ tasks.empty.output }}\n\n  fresh:\n    invoke:\n      tool: \"nika:fetch\"            # SLOT: fetch / read / exec · the fresh data\n      args:\n        url: \"${{ vars.source_url }}\"\n        mode: jq\n        jq: \".records\"\n    on_error:\n      recover: []                   # offline rehearsal · an empty batch, the delta stays quiet\n\n  delta:\n    with:                           # the bindings ARE the edges · previous + fresh → delta\n      previous: ${{ tasks.previous.output }}\n      fresh: ${{ tasks.fresh.output }}\n    invoke:\n      tool: \"nika:json_diff\"        # RFC 6902 · empty patch = nothing new\n      args:\n        before: \"${{ with.previous }}\"\n        after: \"${{ with.fresh }}\"\n\n  process:\n    with:\n      delta: ${{ tasks.delta.output }}\n    when: ${{ size(with.delta) > 0 }}\n    invoke:\n      tool: \"nika:jq\"               # SLOT: the delta job (jq · infer · write…)\n      args:\n        input: \"${{ with.delta }}\"\n        expression: \"length\"\n\n  save_state:\n    with:\n      fresh: ${{ tasks.fresh.output }}\n    invoke:\n      tool: \"nika:write\"\n      args:\n        path: \"${{ vars.state_path }}\"\n        content: \"${{ with.fresh }}\"\n        create_dirs: true\n        overwrite: true\n\noutputs:\n  changes:\n    value: ${{ tasks.delta.output }}\n    description: \"RFC 6902 ops since last run · empty = no-op run\"\n","fanout":"nika: v1\nworkflow:\n  id: fanout-template           # SLOT: kebab-case workflow id\n  description: \"discover N items · process in parallel · merge\"   # SLOT\n\nmodel: ollama/qwen3.5:4b           # SLOT: provider/model · local · zero key\n\nvars:\n  collection_source: \"./items\"      # SLOT: where the collection comes from\n\ntasks:\n  discover:\n    invoke:                         # SLOT: glob / fetch sitemap / exec + jq split\n      tool: \"nika:glob\"\n      args: { pattern: \"${{ vars.collection_source }}/*.md\" }\n\n  process:\n    with:\n      discover: ${{ tasks.discover.output }}\n    for_each: ${{ with.discover }}\n    max_parallel: 4                 # SLOT: the polite ceiling\n    fail_fast: false\n    timeout: \"60s\"                  # SLOT: per-iteration bound\n    retry:\n      max_attempts: 3\n      backoff_strategy: exponential\n      jitter: true\n    on_error:\n      recover: null                 # a failed item yields null at its index · the batch lives\n    infer:                          # SLOT: the per-item job (any verb)\n      prompt: |\n        Process this item · ${{ item }}\n\n  survivors:\n    with:\n      process: ${{ tasks.process.output }}\n    invoke:                         # the null-aware fan-in · order preserved\n      tool: \"nika:jq\"\n      args:\n        input: ${{ with.process }}\n        # `. // []` · an EMPTY discovery skips the whole for_each (null\n        # upstream) — the fan-in must survive its own quiet day.\n        expression: \"(. // []) | [ .[] | select(. != null) ]\"\n\n  merge:\n    with:\n      survivors: ${{ tasks.survivors.output }}\n    infer:\n      prompt: |\n        # SLOT: the fan-in · the survivors array (failed items filtered)\n        Merge these results into one report · ${{ with.survivors }}\n\noutputs:\n  report: ${{ tasks.merge.output }}\n","gate-and-act":"nika: v1\nworkflow:\n  id: gate-and-act-template     # SLOT: kebab-case workflow id\n  description: \"watch a value · act only when the condition holds\"   # SLOT\n\nvars:\n  source_url: \"https://api.example.com/v1/value\"   # SLOT: what to watch\n  threshold: 100                    # SLOT: the trigger condition value\n\nsecrets:\n  webhook:\n    source: env\n    key: ALERTS_WEBHOOK_URL         # SLOT: where the act lands\n    egress:\n      - to: \"nika:notify\"\n        host_from_self: true        # the secret value IS the destination URL\n\ntasks:\n  check:\n    invoke:\n      tool: \"nika:fetch\"\n      args:\n        url: \"${{ vars.source_url }}\"\n        mode: jq\n        jq: \".\"\n    output:\n      value: \".value\"               # SLOT: the jq path to the watched field\n    on_error:\n      # Offline rehearsal · a sample UNDER the threshold — the gate stays\n      # closed, the skeleton runs green before you wire the real source.\n      recover: { value: 42 }\n\n  act:\n    with:\n      value: ${{ tasks.check.value }}   # the binding IS the edge · check → act\n    # when: is a SKIP gate — routing, not failure (a skipped task is not an error)\n    when: ${{ with.value > vars.threshold }}   # SLOT: the CEL condition\n    invoke:\n      tool: \"nika:notify\"           # SLOT: the action · notify / write / exec\n      args:\n        channel: webhook\n        target: \"${{ secrets.webhook }}\"\n        message: \"Threshold crossed · ${{ with.value }}\"   # SLOT\n        severity: warning\n\noutputs:\n  value: ${{ tasks.check.value }}\n","human-gated-ship":"nika: v1\nworkflow:\n  id: human-gated-ship-template  # SLOT: kebab-case workflow id\n  description: \"verify in parallel · human GO · act · record\"   # SLOT\n\npermits:                            # SLOT: the blast radius · default-deny once present\n  exec: [\"echo\"]                    # SLOT: ONLY the programs the gates + act run (argv form)\n  tools: [\"nika:assert\", \"nika:prompt\", \"nika:notify\"]\n  net: { http: [\"hooks.slack.com\"] }   # SLOT: the webhook host · nothing else may leave\n\nsecrets:\n  webhook:\n    source: env\n    key: TEAM_WEBHOOK_URL           # SLOT: where the record lands\n    egress:\n      - to: \"nika:notify\"\n        host_from_self: true        # the secret value IS the destination URL\n\ntasks:\n  # ── the verification wave · all checks run in parallel ──\n  check_a:\n    exec:\n      command: [\"echo\", \"ok\"]        # SLOT: gate 1 (argv form · injection-safe)\n      capture: structured\n\n  check_b:\n    exec:\n      command: [\"echo\", \"ok\"]        # SLOT: gate 2\n      capture: structured\n\n  gates:\n    with:\n      all_green: ${{ tasks.check_a.output.exit_code == 0 && tasks.check_b.output.exit_code == 0 }}   # two value edges · one boundary expression\n    invoke:\n      tool: \"nika:assert\"\n      args:\n        condition: \"${{ with.all_green }}\"\n        message: \"A gate is RED: refusing to proceed\"   # SLOT\n\n  human:\n    after:\n      gates: succeeded              # state, no data · no question until the board is green\n    invoke:\n      # the prompt PAUSES the run (exit 4 · not a failure) — answer and resume:\n      #   nika run --resume <trace> --answer human=yes\n      tool: \"nika:prompt\"\n      args:\n        message: \"All gates GREEN. Proceed?\"   # SLOT: the decision, fully informed\n        default: false\n\n  act:\n    with:\n      go: ${{ tasks.human.output }}   # the answer crosses as a value edge\n    when: ${{ with.go == true }}\n    exec:\n      command: [\"echo\", \"shipped\"]   # SLOT: the irreversible action (argv · program must be in permits.exec)\n      # default capture · a failing ship fails LOUDLY (NIKA-EXEC-001):\n      # never `capture: structured` on the irreversible step (exit codes\n      # would become data and a red ship would read as success)\n\n  record:\n    after:\n      act: terminal                 # the always-pattern · runs on success, failure, OR refusal\n    with:\n      acted: ${{ tasks.act.status }}   # observe the outcome · same pass-set as the after edge\n    invoke:\n      tool: \"nika:notify\"\n      args:\n        channel: webhook\n        target: \"${{ secrets.webhook }}\"\n        message: \"Run finished · act=${{ with.acted }}\"   # SLOT · success | failure | skipped\n        severity: info\n\noutputs:\n  acted: ${{ tasks.act.status }}\n","media-asset-pack":"nika: v1\nworkflow:\n  id: media-asset-pack-template # SLOT: kebab-case workflow id\n  description: \"brief → render → manifest\"  # SLOT: one honest sentence\n\nmodel: ollama/qwen3.5:4b            # SLOT: provider/model · local · zero key\n\nvars:\n  subject: \"a calm cosmic landing hero\"   # SLOT: what the asset is about\n  out_dir: \"./out/assets\"           # SLOT: where assets land\n\ntasks:\n  brief:\n    infer:\n      max_tokens: 600\n      prompt: |\n        # SLOT: the creative direction · style · constraints\n        Write one vivid, concrete image prompt for: ${{ vars.subject }}.\n        No text in the image · no watermark · a calm central zone.\n      schema:\n        type: object\n        additionalProperties: false\n        properties:\n          image_prompt: { type: string }\n        required: [image_prompt]\n\n  render:\n    with:\n      brief_image_prompt: ${{ tasks.brief.output.image_prompt }}\n    invoke:\n      tool: \"nika:image_generate\"\n      args:\n        provider: mock              # SLOT: local | openai | gemini | xai (local/mock first)\n        prompt: \"${{ with.brief_image_prompt }}\"\n        output_dir: \"${{ vars.out_dir }}\"\n        filename_prefix: \"asset\"    # SLOT: filename stem\n\n  manifest:\n    with:\n      brief: ${{ tasks.brief.output }}\n      render: ${{ tasks.render.output }}\n    invoke:\n      tool: \"nika:jq\"\n      args:\n        expression: \"{ brief: .[0], images: .[1].images }\"\n        input:\n          - \"${{ with.brief }}\"\n          - \"${{ with.render }}\"\n\n  persist:\n    with:\n      manifest: ${{ tasks.manifest.output }}\n    invoke:\n      tool: \"nika:write\"\n      args:\n        path: \"${{ vars.out_dir }}/manifest.json\"\n        create_dirs: true\n        content: \"${{ with.manifest }}\"\n\noutputs:\n  manifest: ${{ tasks.manifest.output }}  # SLOT: the callable contract\n","website-brief":"nika: v1\nworkflow:\n  id: website-brief-template    # SLOT: kebab-case workflow id\n  description: \"crawl → brief → persist\"   # SLOT: one honest sentence\n\nmodel: ollama/qwen3.5:4b            # SLOT: provider/model · local · zero key\n\nvars:\n  site_url: \"https://example.com\"   # SLOT: the site to understand\n  out_path: \"./out/brief.json\"      # SLOT: where the brief lands\n\ntasks:\n  crawl_site:\n    invoke:\n      tool: \"nika:fetch\"\n      args:\n        url: \"${{ vars.site_url }}\"\n        traverse: { max_pages: 5 }  # SLOT: crawl bound · 1..=25 (robots honored)\n\n  brief:\n    with:\n      crawl_site: ${{ tasks.crawl_site.output }}\n    infer:\n      max_tokens: 1200\n      prompt: |\n        # SLOT: the one model job · what should the brief capture?\n        From this site crawl, produce a creative brief: the domain of\n        activity, the dominant visual theme, the audience, the usable\n        colors and image assets.\n        Crawl digest · ${{ with.crawl_site }}\n      schema:                       # SLOT: the typed shape downstream tasks rely on\n        type: object\n        additionalProperties: false\n        properties:\n          domain: { type: string }\n          theme: { type: string }\n          audience: { type: string }\n          colors: { type: array, items: { type: string } }\n          assets: { type: array, items: { type: string } }\n        required: [domain, theme, audience, colors, assets]\n\n  persist:\n    with:\n      brief: ${{ tasks.brief.output }}\n    invoke:\n      tool: \"nika:write\"\n      args:\n        path: \"${{ vars.out_path }}\"\n        create_dirs: true\n        content: \"${{ with.brief }}\"   # ALWAYS pass content\n\noutputs:\n  brief: ${{ tasks.brief.output }}   # SLOT: the callable contract\n"}
the playground
Write Nika, checked live.

Try it right here.
Real Nika, validated as you type: the same NIKA codes the engine raises, with their fixes. Everything runs in this tab; nothing is sent anywhere.
TemplatesShowcase
chain.nika.yamlvalid
The plan · live3 tasks · 3 waves
gatherinvokenika:read
thinkinferprompt
persistinvokenika:write
The blast radius
no permits: declared. Add one and the file becomes its own blast radius (try the human-gated-ship template)
runs locally:→ nika run chain.nika.yaml
client-only · nothing leaves the tab · the engine's own NIKA codes, live
Learn the file, line by line See real workflows Read the spec