nika: v1
workflow:
  id: pr-review-fanout
  description: "changed files → one read-only review agent each → merged REVIEW.md"

model: ollama/qwen3.5:4b   # local tool-calling model · swap for anthropic/claude-sonnet-4-6 for depth

vars:
  base_ref: "main"

tasks:
  changed:
    exec:
      command: ["git", "diff", "--name-only", "${{ vars.base_ref }}...HEAD"]

  files:
    with:
      changed: ${{ tasks.changed.output }}
    invoke:
      tool: "nika:jq"
      args:
        input: "${{ with.changed }}"
        expression: 'split("\n") | map(select(length > 0))'

  todo_sweep:
    invoke:
      tool: "nika:grep"
      args:
        pattern: "TODO|FIXME|HACK"
        path: "./src"

  reviews:
    with:
      files: ${{ tasks.files.output }}
    for_each: ${{ with.files }}
    max_parallel: 4
    fail_fast: false
    on_error:
      recover: null                    # a budget-exhausted review yields null · the swarm lives
    agent:
      system: "You are a precise code reviewer. Read the file, then finish with ONLY the schema'd object ({file, findings: [{severity, message, line}]} · severity exactly one of blocker|high|med|low), then call nika:done."
      prompt: "Review ${{ item }} · bugs first, then risky patterns. Read it before judging."
      tools:
        - "nika:read"                  # read-only swarm · least privilege
        - "nika:done"
      max_turns: 6
      max_tokens_total: 30000
      schema:
        type: object
        required: [file, findings]
        properties:
          file: { type: string }
          findings:
            type: array
            items:
              type: object
              required: [severity, message]
              properties:
                severity: { type: string, enum: [blocker, high, med, low] }
                message: { type: string }
                line: { type: integer }

  merged:
    with:
      reviews: ${{ tasks.reviews.output }}
    invoke:
      tool: "nika:jq"
      args:
        input: "${{ with.reviews }}"
        # `. // []` · a clean diff SKIPS the swarm (empty for_each → null
        # upstream) and the fan-in must survive its own good news.
        expression: '(. // []) | map(select(. != null)) | map(.findings[] + {file: .file}) | sort_by(.severity)'

  summary:
    with:
      merged: ${{ tasks.merged.output }}
      todo_sweep: ${{ tasks.todo_sweep.output }}
    infer:
      prompt: |
        Merge these review findings into REVIEW.md · blockers first ·
        ${{ with.merged }}
        Open TODO debt found by grep ·
        ${{ with.todo_sweep }}
        End with a verdict · ship / fix-first / redesign.

  save:
    with:
      summary: ${{ tasks.summary.output }}
    invoke:
      tool: "nika:write"
      args:
        path: "./REVIEW.md"
        content: "${{ with.summary }}"

outputs:
  findings:
    value: ${{ tasks.merged.output }}
    description: "All findings, severity-sorted, with file attribution"
  review: ${{ tasks.summary.output }}

{"a":{"graph_format":2,"workflow":"pr-review-fanout","nodes":[{"id":"changed","verb":"exec","permits":["exec: git"]},{"id":"todo_sweep","verb":"invoke","tool":"nika:grep","permits":["fs.read: ./src/**","tool: nika:grep"]},{"id":"files","verb":"invoke","tool":"nika:jq","permits":["tool: nika:jq"]},{"id":"reviews","verb":"agent","model":"ollama/qwen3.5:4b","fan_out":{"kind":"expression"},"permits":["tool: nika:done","tool: nika:read"]},{"id":"merged","verb":"invoke","tool":"nika:jq","permits":["tool: nika:jq"]},{"id":"summary","verb":"infer","model":"ollama/qwen3.5:4b","permits":[]},{"id":"save","verb":"invoke","tool":"nika:write","permits":["fs.write: ./REVIEW.md","tool: nika:write"]}],"edges":[{"from":"changed","to":"files","kind":"value"},{"from":"files","to":"reviews","kind":"value"},{"from":"merged","to":"summary","kind":"value"},{"from":"reviews","to":"merged","kind":"value"},{"from":"summary","to":"save","kind":"value"},{"from":"todo_sweep","to":"summary","kind":"value"}]},"engine":"0.105.0"}

showcase · tier 3 · builders

PR review swarm

One read-only review agent per changed file, in parallel and under budget. jq merges the findings.

Big PRs get deep reviews, because attention now scales with the diff. · conformance-gated in nika-spec ↗ · re-proven at every push

The whole file

7 tasks · 6 waves · the plan falls out of the bindings, nothing is scheduled by hand.

t3-pr-review-fanout.nika.yamlsource

1nika: v12workflow:3  id: pr-review-fanout4  description: "changed files → one read-only review agent each → merged REVIEW.md"56model: ollama/qwen3.5:4b   # local tool-calling model · swap for anthropic/claude-sonnet-4-6 for depth78vars:9  base_ref: "main"1011tasks:12  changed:13    ▷exec:14      command: ["git", "diff", "--name-only", "${{ vars.base_ref }}...HEAD"]1516  files:17    with:18      changed: ${{ tasks.changed.output }}19    ◆invoke:20      tool: "nika:jq"21      args:22        input: "${{ with.changed }}"23        expression: 'split("\n") | map(select(length > 0))'2425  todo_sweep:26    ◆invoke:27      tool: "nika:grep"28      args:29        pattern: "TODO|FIXME|HACK"30        path: "./src"3132  reviews:33    with:34      files: ${{ tasks.files.output }}35    for_each: ${{ with.files }}36    max_parallel: 437    fail_fast: false38    on_error:39      recover: null                    # a budget-exhausted review yields null · the swarm lives40    ✦agent:41      system: "You are a precise code reviewer. Read the file, then finish with ONLY the schema'd object ({file, findings: [{severity, message, line}]} · severity exactly one of blocker|high|med|low), then call nika:done."42      prompt: "Review ${{ item }} · bugs first, then risky patterns. Read it before judging."43      tools:44        - "nika:read"                  # read-only swarm · least privilege45        - "nika:done"46      max_turns: 647      max_tokens_total: 3000048      schema:49        type: object50        required: [file, findings]51        properties:52          file: { type: string }53          findings:54            type: array55            items:56              type: object57              required: [severity, message]58              properties:59                severity: { type: string, enum: [blocker, high, med, low] }60                message: { type: string }61                line: { type: integer }6263  merged:64    with:65      reviews: ${{ tasks.reviews.output }}66    ◆invoke:67      tool: "nika:jq"68      args:69        input: "${{ with.reviews }}"70        # `. // []` · a clean diff SKIPS the swarm (empty for_each → null71        # upstream) and the fan-in must survive its own good news.72        expression: '(. // []) | map(select(. != null)) | map(.findings[] + {file: .file}) | sort_by(.severity)'7374  summary:75    with:76      merged: ${{ tasks.merged.output }}77      todo_sweep: ${{ tasks.todo_sweep.output }}78    ◇infer:79      prompt: |80        Merge these review findings into REVIEW.md · blockers first ·81        ${{ with.merged }}82        Open TODO debt found by grep ·83        ${{ with.todo_sweep }}84        End with a verdict · ship / fix-first / redesign.8586  save:87    with:88      summary: ${{ tasks.summary.output }}89    ◆invoke:90      tool: "nika:write"91      args:92        path: "./REVIEW.md"93        content: "${{ with.summary }}"9495outputs:96  findings:97    value: ${{ tasks.merged.output }}98    description: "All findings, severity-sorted, with file attribution"99  review: ${{ tasks.summary.output }}100

nika inspect · engine 0.105.0 · 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 verbexec verbinvoke verbagent verbinfer toolnika:jq toolnika:grep toolnika:write