feat(loops+improvement): dynamic loop driver + identity-gated optimizePrompt

src/errors.ts

@@ -99,3 +99,20 @@ export class RuntimeRunStateError extends AgentEvalError {
     super('validation', message, options)
   }
 }
+
+/**
+ * @stable
+ *
+ * The dynamic-loop planner returned an unusable topology move — the LLM emitted
+ * no parseable envelope, an unknown `kind`, or a structurally-invalid move
+ * (e.g. a fanout with zero tasks). This is a structural failure of the
+ * agent-authored topology, not a config mistake: the planner ran but its output
+ * cannot drive the kernel. Carries `validation` so cross-package handlers can
+ * pattern-match without importing the runtime. Fail loud — never substitute a
+ * default move, or the loop silently runs a topology nobody chose.
+ */
+export class PlannerError extends AgentEvalError {
+  constructor(message: string, options?: { cause?: unknown }) {
+    super('validation', message, options)
+  }
+}

src/improvement/index.ts

@@ -1,11 +1,14 @@
 /**
- * `@tangle-network/agent-runtime` improvement drivers — implementations of
- * agent-eval's `ImprovementDriver` contract.
+ * `@tangle-network/agent-runtime` improvement — two entry points onto
+ * agent-eval's `runImprovementLoop`:
  *
- * ONE driver (`improvementDriver`) owns the candidate lifecycle; pluggable
- * `CandidateGenerator`s set the cost/capability dial:
- *   - `reflectiveGenerator` — cheap, no sandbox, applies pre-drafted patches
- *   - `agenticGenerator`     — full coding harness in the worktree, multi-shot
+ *   - `improvementDriver` (CODE surface) — owns the candidate lifecycle via a
+ *     pluggable `CandidateGenerator`:
+ *       - `reflectiveGenerator` — cheap, no sandbox, applies pre-drafted patches
+ *       - `agenticGenerator`     — full coding harness in the worktree, multi-shot
+ *   - `optimizePrompt` (TEXT surface) — identity-gated optimization of any
+ *     system / planner prompt. Defaults to agent-eval's `gepaDriver` +
+ *     `heldOutGate`; returns the baseline unless the held-out gate ships a win.
  */
 
 export { type AgenticGeneratorOptions, agenticGenerator } from './agentic-generator'
@@ -14,4 +17,10 @@ export {
   type ImprovementDriverOptions,
   improvementDriver,
 } from './improvement-driver'
+export {
+  type OptimizePromptOptions,
+  type OptimizePromptReflection,
+  type OptimizePromptResult,
+  optimizePrompt,
+} from './optimize-prompt'
 export { type ReflectiveGeneratorOptions, reflectiveGenerator } from './reflective-generator'

src/improvement/optimize-prompt.ts

@@ -0,0 +1,242 @@
+/**
+ * @experimental
+ *
+ * `optimizePrompt` — identity-gated optimization for any TEXT prompt surface
+ * (system prompt, planner prompt, judge rubric, skill doc).
+ *
+ * The text-surface sibling to this module's `improvementDriver` (the
+ * CODE-surface / worktree path). Both feed agent-eval's `runImprovementLoop`;
+ * this one defaults the driver to agent-eval's `gepaDriver` (reflective text
+ * mutator) and the gate to `heldOutGate`.
+ *
+ * IDENTITY-GATED BY CONSTRUCTION — the whole point. The loop runs evals,
+ * collects per-scenario signal, proposes candidates, and the gate compares
+ * candidate-vs-baseline ON THE HELDOUT. `result.prompt` is the baseline
+ * (identity) UNLESS the gate decided `'ship'`. So wiring a surface up is safe:
+ * a surface with no beneficial mutation simply keeps its baseline. You never
+ * regress by registering a prompt — you only ever improve when the held-out
+ * data earns it.
+ *
+ * Generic over the runtime: `runWithPrompt` is the only domain seam — given a
+ * candidate prompt + scenario, run it however the surface runs (sandbox
+ * `streamPrompt`, a `runLoop`, a direct model call) and return the artifact the
+ * judges score. The optimizer never assumes how a prompt is executed.
+ */
+
+import type { LlmClientOptions } from '@tangle-network/agent-eval'
+import type {
+  CampaignResult,
+  CampaignStorage,
+  DispatchContext,
+  Gate,
+  GateResult,
+  ImprovementDriver,
+  JudgeConfig,
+  RunImprovementLoopResult,
+  Scenario,
+} from '@tangle-network/agent-eval/campaign'
+import { gepaDriver, heldOutGate, runImprovementLoop } from '@tangle-network/agent-eval/campaign'
+import { ConfigError } from '../errors'
+
+/** Reflection config for the default `gepaDriver`. Omit when passing a custom
+ *  `driver`. */
+export interface OptimizePromptReflection {
+  /** Router transport for the reflection model. */
+  llm: LlmClientOptions
+  /** Model that performs the reflective rewrite. */
+  model: string
+  /** What is being optimized — orients the reflection prompt. Default
+   *  `'system prompt'`. */
+  target?: string
+  /** Surface-specific mutation levers offered to the reflector. */
+  mutationPrimitives?: string[]
+  /** H2 (`## Foo`) headings that MUST survive every candidate. gepaDriver's
+   *  only structural guard — load-bearing sections of the prompt should be
+   *  `##` headings so a rewrite cannot drop them. */
+  preserveSections?: string[]
+  /** Max sentence-level edits per candidate vs the parent (a textual learning
+   *  rate). Caps a rewrite from wiping prior rules in one generation. */
+  maxSentenceEdits?: number
+}
+
+/** @experimental */
+export interface OptimizePromptOptions<TScenario extends Scenario, TArtifact> {
+  /** The prompt being optimized — the identity baseline the gate protects. */
+  baselinePrompt: string
+  /** Domain seam: run a candidate prompt against a scenario → artifact the
+   *  judges score. The optimizer is agnostic to HOW the prompt runs. */
+  runWithPrompt: (prompt: string, scenario: TScenario, ctx: DispatchContext) => Promise<TArtifact>
+  /** Training pool — scored each generation to rank candidates. */
+  scenarios: TScenario[]
+  /** Held out of training — scored ONLY for the gate's baseline-vs-winner
+   *  delta. Disjoint from `scenarios`; this is what makes promotion measure
+   *  generalization, not memorization. */
+  holdoutScenarios: TScenario[]
+  /** Scorers — deterministic checks or LLM judges. */
+  judges: JudgeConfig<TArtifact, TScenario>[]
+  /** Where artifacts + traces land (opaque key under in-memory storage). */
+  runDir: string
+  /** Default driver = `gepaDriver` built from this. Required UNLESS `driver`
+   *  is supplied. */
+  reflection?: OptimizePromptReflection
+  /** Override the improvement strategy (custom driver / deterministic tests). */
+  driver?: ImprovementDriver
+  /** Override the promotion gate. Default `heldOutGate` over `holdoutScenarios`
+   *  — zero extra LLM. Wrap `defaultProductionGate` for red-team/reward-hacking
+   *  hardening on production wiring. */
+  gate?: Gate<TArtifact, TScenario>
+  /** Minimum held-out composite lift to ship, forwarded to the default
+   *  `heldOutGate`. When omitted the gate uses its own default. */
+  deltaThreshold?: number
+  /** Candidates proposed per generation. Default 4. */
+  populationSize?: number
+  /** Generations to run. Default 3. */
+  maxGenerations?: number
+  /** Candidates carried to the next generation. Default 2. */
+  promoteTopK?: number
+  /** Storage backend. Pass `inMemoryCampaignStorage()` for filesystem-less /
+   *  test runs. Default: Node filesystem. */
+  storage?: CampaignStorage
+  /** Reproducibility seed. Default 42. */
+  seed?: number
+  /** Per-scenario replicates for CI bands. Default 1. */
+  reps?: number
+  /** Max concurrent cells. Default 2. */
+  maxConcurrency?: number
+  /** Test seam — override the wall clock. */
+  now?: () => Date
+  /** On a shipped gate: `'pr'` opens a PR, `'none'` just reports. Default
+   *  `'none'`. */
+  autoOnPromote?: 'pr' | 'none'
+  ghOwner?: string
+  ghRepo?: string
+}
+
+/** @experimental */
+export interface OptimizePromptResult<TArtifact, TScenario extends Scenario> {
+  /** The prompt to USE. Identity (the baseline) unless the gate shipped a
+   *  winner — so a caller can always assign `result.prompt` unconditionally. */
+  prompt: string
+  /** True only when the gate promoted a candidate over baseline on holdout. */
+  improved: boolean
+  /** The gate's verdict (`'ship' | 'hold' | 'need_more_work' | ...`). */
+  decision: GateResult['decision']
+  /** Human-readable reasons the gate gave. */
+  reasons: string[]
+  /** Mean held-out composite of the baseline. */
+  baselineComposite: number
+  /** Mean held-out composite of the winner candidate. */
+  winnerComposite: number
+  /** Held-out lift (winner − baseline); the gate's `delta` when it reported one. */
+  delta: number
+  /** Why the winner was proposed — present when a shipped winner carried a
+   *  driver rationale. */
+  rationale?: string
+  /** Unified baseline→winner diff (empty when the winner is the baseline). */
+  diff: string
+  /** The full loop result for callers that need generations / campaigns. */
+  raw: RunImprovementLoopResult<TArtifact, TScenario>
+}
+
+/** @experimental */
+export async function optimizePrompt<TScenario extends Scenario, TArtifact>(
+  opts: OptimizePromptOptions<TScenario, TArtifact>,
+): Promise<OptimizePromptResult<TArtifact, TScenario>> {
+  if (!opts.driver && !opts.reflection) {
+    throw new ConfigError(
+      'optimizePrompt: pass `reflection` (builds the default gepaDriver) or a custom `driver`',
+    )
+  }
+  if (opts.scenarios.length === 0) {
+    throw new ConfigError('optimizePrompt: `scenarios` must be non-empty')
+  }
+  if (opts.holdoutScenarios.length === 0) {
+    throw new ConfigError(
+      'optimizePrompt: `holdoutScenarios` must be non-empty (the gate needs it)',
+    )
+  }
+
+  const driver =
+    opts.driver ??
+    gepaDriver({
+      llm: opts.reflection!.llm,
+      model: opts.reflection!.model,
+      target: opts.reflection!.target ?? 'system prompt',
+      mutationPrimitives: opts.reflection!.mutationPrimitives,
+      constraints:
+        opts.reflection!.preserveSections || opts.reflection!.maxSentenceEdits !== undefined
+          ? {
+              preserveSections: opts.reflection!.preserveSections,
+              maxSentenceEdits: opts.reflection!.maxSentenceEdits,
+            }
+          : undefined,
+    })
+
+  const gate =
+    opts.gate ??
+    heldOutGate<TArtifact, TScenario>({
+      scenarios: opts.holdoutScenarios,
+      ...(opts.deltaThreshold !== undefined ? { deltaThreshold: opts.deltaThreshold } : {}),
+    })
+
+  const result = await runImprovementLoop<TScenario, TArtifact>({
+    baselineSurface: opts.baselinePrompt,
+    dispatchWithSurface: (surface, scenario, ctx) => {
+      if (typeof surface !== 'string') {
+        // optimizePrompt is the TEXT-surface entry point; a CodeSurface means
+        // the caller wired the wrong driver. Fail loud — don't silently run the
+        // baseline and report a phantom score.
+        throw new ConfigError(
+          'optimizePrompt: received a CodeSurface — this entry point optimizes string prompts only',
+        )
+      }
+      return opts.runWithPrompt(surface, scenario, ctx)
+    },
+    driver,
+    populationSize: opts.populationSize ?? 4,
+    maxGenerations: opts.maxGenerations ?? 3,
+    ...(opts.promoteTopK !== undefined ? { promoteTopK: opts.promoteTopK } : {}),
+    scenarios: opts.scenarios,
+    holdoutScenarios: opts.holdoutScenarios,
+    judges: opts.judges,
+    gate,
+    autoOnPromote: opts.autoOnPromote ?? 'none',
+    ...(opts.ghOwner !== undefined ? { ghOwner: opts.ghOwner } : {}),
+    ...(opts.ghRepo !== undefined ? { ghRepo: opts.ghRepo } : {}),
+    runDir: opts.runDir,
+    ...(opts.storage !== undefined ? { storage: opts.storage } : {}),
+    ...(opts.seed !== undefined ? { seed: opts.seed } : {}),
+    ...(opts.reps !== undefined ? { reps: opts.reps } : {}),
+    ...(opts.maxConcurrency !== undefined ? { maxConcurrency: opts.maxConcurrency } : {}),
+    ...(opts.now !== undefined ? { now: opts.now } : {}),
+  })
+
+  const improved = result.gateResult.decision === 'ship'
+  const winnerSurface =
+    typeof result.winnerSurface === 'string' ? result.winnerSurface : opts.baselinePrompt
+  const baselineComposite = meanComposite(result.baselineOnHoldout)
+  const winnerComposite = meanComposite(result.winnerOnHoldout)
+
+  return {
+    prompt: improved ? winnerSurface : opts.baselinePrompt,
+    improved,
+    decision: result.gateResult.decision,
+    reasons: result.gateResult.reasons,
+    baselineComposite,
+    winnerComposite,
+    delta: result.gateResult.delta ?? winnerComposite - baselineComposite,
+    ...(improved && result.winnerRationale ? { rationale: result.winnerRationale } : {}),
+    diff: result.promotedDiff,
+    raw: result,
+  }
+}
+
+/** Mean composite over a campaign's per-scenario aggregates. The held-out
+ *  campaigns score one surface across `holdoutScenarios`; averaging the
+ *  per-scenario means gives the single number the gate's delta is built from. */
+function meanComposite(campaign: CampaignResult<unknown, Scenario>): number {
+  const scenarios = Object.values(campaign.aggregates.byScenario)
+  if (scenarios.length === 0) return 0
+  const sum = scenarios.reduce((acc, s) => acc + s.meanComposite, 0)
+  return sum / scenarios.length
+}

src/index.ts

@@ -101,6 +101,7 @@ export {
   ConfigError,
   JudgeError,
   NotFoundError,
+  PlannerError,
   RuntimeRunStateError,
   ValidationError,
 } from './errors'