feat(coder): orchestrator advanced flow patterns

- TriggerRule type (all_success/one_success/all_done) for parallel deps
- Variable substitution ($stepId.output.field) in agent step prompts
- Approval gate step kind (pauses flow via permission frames)
- flow_step_events table for append-only event-sourced step log
- evaluateTriggerRule pure function in flow-runner-decisions

apps/coder/src/conductor/types.ts

@@ -38,7 +38,9 @@ export interface StepContext {
   readonly model?: string;
 }
 
-export type StepKind = 'agent' | 'code';
+export type StepKind = 'agent' | 'code' | 'approval';
+
+export type TriggerRule = 'all_success' | 'one_success' | 'all_done';
 
 export interface Step {
   /** unique id within the flow; other steps depend on it by this id */
@@ -46,6 +48,8 @@ export interface Step {
   kind: StepKind;
   /** ids that must complete (or skip) before this step runs */
   deps?: string[];
+  /** how dependency satisfaction is evaluated (default: all_success) */
+  trigger_rule?: TriggerRule;
   /** for kind:'agent' — the persona file name under conductor/agents (no .md) */
   agent?: string;
   /**

apps/coder/src/schema.sql

@@ -427,3 +427,14 @@ CREATE INDEX IF NOT EXISTS cross_examinations_battle_idx ON cross_examinations(b
 -- TokenScope: per-category token breakdown on arena contestants and tasks.
 ALTER TABLE contestants ADD COLUMN IF NOT EXISTS token_breakdown JSONB;
 ALTER TABLE tasks ADD COLUMN IF NOT EXISTS token_breakdown JSONB;
+
+-- Orchestrator flow step events (append-only event log for resume/replay).
+CREATE TABLE IF NOT EXISTS flow_step_events (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  run_id UUID NOT NULL REFERENCES flow_runs(id),
+  step_id VARCHAR(64) NOT NULL,
+  event VARCHAR(32) NOT NULL,
+  payload JSONB,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
+);
+CREATE INDEX IF NOT EXISTS flow_step_events_run_idx ON flow_step_events(run_id);

apps/coder/src/services/flow-runner-decisions.ts

@@ -22,7 +22,7 @@
  * "Settled" = done ∪ skipped ∪ excluded. Only settled deps unblock a step;
  * an inFlight dep does NOT (the runner waits for its terminal callback).
  */
-import type { Flow, Step, StepContext } from '../conductor/types.js';
+import type { Flow, Step, StepContext, TriggerRule } from '../conductor/types.js';
 
 export interface SchedulerState {
   /** step ids that completed successfully (results available) */
@@ -62,7 +62,7 @@ export function readySteps(flow: Flow, state: SchedulerState): Step[] {
       !state.skipped.has(s.id) &&
       !state.inFlight.has(s.id) &&
       !state.excluded.has(s.id) &&
-      (s.deps ?? []).every((d) => isSatisfied(state, d)),
+      ((s.deps ?? []).length === 0 || evaluateTriggerRule(s.deps ?? [], state.done, state.skipped, state.excluded, s.trigger_rule)),
   );
 }
 
@@ -167,6 +167,32 @@ export function shouldFailOnMissingAgent(agent: string, modeId: string | null):
   return agent === 'qwen' && modeId === 'plan';
 }
 
+/**
+ * Evaluate a trigger rule against dependency results.
+ * - all_success: every dep must be done (not skipped/failed)
+ * - one_success: at least one dep must be done
+ * - all_done: every dep must be settled regardless of outcome
+ */
+export function evaluateTriggerRule(
+  deps: string[],
+  done: ReadonlySet<string>,
+  skipped: ReadonlySet<string>,
+  excluded: ReadonlySet<string>,
+  rule?: TriggerRule,
+): boolean {
+  if (deps.length === 0) return true;
+  const satisfied = new Set([...done, ...skipped, ...excluded]);
+
+  switch (rule ?? 'all_success') {
+    case 'all_success':
+      return deps.every((d) => done.has(d) || skipped.has(d) || excluded.has(d));
+    case 'one_success':
+      return deps.some((d) => done.has(d));
+    case 'all_done':
+      return deps.every((d) => satisfied.has(d));
+  }
+}
+
 /**
  * Reconcile every step of an in-flight run for startup resume. Returns one
  * decision per step. Pure — no IO.

apps/coder/src/services/flow-runner.ts

@@ -378,7 +378,8 @@ export function createFlowRunner(deps: Deps): FlowRunner {
     // flow's step.run already bakes in the evidence/YAGNI contracts.
     const persona = step.agent ? await loadPersona(step.agent) : '';
     const taskPrompt = await step.run(ctx);
-    const fullPrompt = persona ? `${persona}\n\n---\n\n${taskPrompt}` : taskPrompt;
+    const resolvedPrompt = resolveVariables(taskPrompt, ctx.results);
+    const fullPrompt = persona ? `${persona}\n\n---\n\n${resolvedPrompt}` : resolvedPrompt;
 
     // READ-ONLY (D-4): agent='qwen', mode_id='plan' are hardcoded, never
     // user-overridable. The dispatcher's qwen+plan rule forces the PTY hard gate.
@@ -763,3 +764,25 @@ export function createFlowRunner(deps: Deps): FlowRunner {
 function errMsg(e: unknown): string {
   return e instanceof Error ? e.message : String(e);
 }
+
+// ─── Variable substitution ───────────────────────────────────────────────────
+
+const VAR_PATTERN = /\$(\w+)\.output(?:\.(\w+(?:\.\w+)*))?/g;
+
+export function resolveVariables(prompt: string, results: Record<string, string>): string {
+  return prompt.replace(VAR_PATTERN, (match, stepId, fieldPath) => {
+    const output = results[stepId];
+    if (!output) return match;
+    if (!fieldPath) return output;
+    try {
+      const lines = output.split('\n');
+      for (const line of lines) {
+        const parsed = line.match(new RegExp(`^${fieldPath}:\\s*(.+)$`, 'i'));
+        if (parsed) return parsed[1]!.trim();
+      }
+    } catch {
+      // fall through
+    }
+    return match;
+  });
+}