feat(routing): tier-aware fallback, output format guard, task decomposition

.env.example

@@ -269,6 +269,18 @@ AGENTS_DEFAULT_MODEL=haiku
 AGENTS_MAX_STEPS=15
 AGENTS_TIMEOUT=300000
 
+# ==============================================================================
+# Task Decomposition (opt-in; requires AGENTS_ENABLED=true)
+# ==============================================================================
+# Breaks complex, divisible tasks into focused subtasks run with isolated
+# context (parallel where independent), then synthesizes the result. A cost-aware
+# gate decides WHEN to decompose — decomposition can cost MORE than it saves on
+# small/indivisible tasks, so it only triggers on complex, large, divisible work.
+# Exposed as the DecomposeTask tool. All other settings (models, gate thresholds,
+# shadow mode) are hardcoded in src/config/index.js.
+
+TASK_DECOMPOSITION_ENABLED=false
+
 # ==============================================================================
 # MCP Sandbox Configuration
 # ==============================================================================

Dockerfile

@@ -23,7 +23,7 @@ FROM node:24-alpine AS runtime
 
 ARG VCS_REF
 ARG BUILD_DATE
-ARG VERSION=9.5.0
+ARG VERSION=9.6.0
 
 LABEL org.opencontainers.image.title="Lynkr" \
       org.opencontainers.image.description="Universal LLM proxy for Claude Code, Cursor, and AI coding tools" \

docker-compose.yml

@@ -3,7 +3,7 @@ services:
   lynkr:
     build: .
     container_name: lynkr
-    image: lynkr:9.5.0
+    image: lynkr:9.6.0
     ports:
       - "8081:8081"
     extra_hosts:
@@ -329,7 +329,7 @@ services:
       retries: 3
       start_period: 40s
     labels:
-      - "com.lynkr.version=9.5.0"
+      - "com.lynkr.version=9.6.0"
       - "com.lynkr.description=Claude Code proxy with multi-provider support"
     # Uncomment to set resource limits
     # deploy:

package.json

@@ -1,6 +1,6 @@
 {
   "name": "lynkr",
-  "version": "9.5.0",
+  "version": "9.6.0",
   "description": "Self-hosted LLM gateway and tier-routing proxy for Claude Code, Cursor, and Codex. Routes across Ollama, AWS Bedrock, OpenRouter, Databricks, Azure OpenAI, llama.cpp, and LM Studio with prompt caching, MCP tools, and 60-80% cost savings.",
   "main": "index.js",
   "bin": {
@@ -16,7 +16,7 @@
     "dev": "nodemon index.js",
     "lint": "eslint src index.js",
     "test": "npm run test:unit && npm run test:performance",
-    "test:unit": "DATABRICKS_API_KEY=test-key DATABRICKS_API_BASE=http://test.com node --test test/routing.test.js test/hybrid-routing-integration.test.js test/web-tools.test.js test/passthrough-mode.test.js test/openrouter-error-resilience.test.js test/format-conversion.test.js test/azure-openai-config.test.js test/azure-openai-format-conversion.test.js test/azure-openai-routing.test.js test/azure-openai-streaming.test.js test/azure-openai-error-resilience.test.js test/azure-openai-integration.test.js test/openai-integration.test.js test/toon-compression.test.js test/llamacpp-integration.test.js test/resilience.test.js test/telemetry-routing.test.js test/memory/store.test.js test/memory/surprise.test.js test/memory/extractor.test.js test/memory/search.test.js test/memory/retriever.test.js test/distill.test.js test/large-payload.test.js test/code-mode.test.js test/prompt-cache-injection.test.js test/risk-analyzer.test.js test/interaction-block.test.js test/preflight.test.js test/token-reduction.test.js test/session-affinity.test.js test/model-registry-cost.test.js",
+    "test:unit": "DATABRICKS_API_KEY=test-key DATABRICKS_API_BASE=http://test.com node --test test/routing.test.js test/hybrid-routing-integration.test.js test/web-tools.test.js test/passthrough-mode.test.js test/openrouter-error-resilience.test.js test/format-conversion.test.js test/azure-openai-config.test.js test/azure-openai-format-conversion.test.js test/azure-openai-routing.test.js test/azure-openai-streaming.test.js test/azure-openai-error-resilience.test.js test/azure-openai-integration.test.js test/openai-integration.test.js test/toon-compression.test.js test/llamacpp-integration.test.js test/resilience.test.js test/telemetry-routing.test.js test/memory/store.test.js test/memory/surprise.test.js test/memory/extractor.test.js test/memory/search.test.js test/memory/retriever.test.js test/distill.test.js test/large-payload.test.js test/code-mode.test.js test/prompt-cache-injection.test.js test/risk-analyzer.test.js test/interaction-block.test.js test/preflight.test.js test/token-reduction.test.js test/session-affinity.test.js test/model-registry-cost.test.js test/task-decomposition.test.js test/output-format-guard.test.js test/tier-fallback.test.js",
     "test:memory": "DATABRICKS_API_KEY=test-key DATABRICKS_API_BASE=http://test.com node --test test/memory/store.test.js test/memory/surprise.test.js test/memory/extractor.test.js test/memory/search.test.js test/memory/retriever.test.js",
     "test:new-features": "DATABRICKS_API_KEY=test-key DATABRICKS_API_BASE=http://test.com node --test test/passthrough-mode.test.js test/openrouter-error-resilience.test.js test/format-conversion.test.js",
     "test:performance": "DATABRICKS_API_KEY=test-key DATABRICKS_API_BASE=http://test.com node test/hybrid-routing-performance.test.js && DATABRICKS_API_KEY=test-key DATABRICKS_API_BASE=http://test.com node test/performance-tests.js",

src/agents/decomposition/dispatcher.js

@@ -0,0 +1,185 @@
+/**
+ * Subtask dispatcher (Phase 3).
+ *
+ * Executes a validated plan respecting its dependency DAG:
+ *   - subtasks are grouped into topological "levels" (Kahn's algorithm)
+ *   - subtasks in the same level have no dependency on each other → run in
+ *     parallel via the existing ParallelCoordinator (spawnParallel)
+ *   - a subtask receives ONLY its own prompt plus the compressed results of the
+ *     subtasks it depends on (context isolation — the token win)
+ *
+ * The spawn functions are injectable for testing.
+ */
+
+const logger = require("../../logger");
+
+// Cap how much of a dependency's result we forward, to preserve the
+// context-isolation savings (subagents already return summaries; this bounds
+// pathological cases).
+const MAX_CONTEXT_CHARS = 2000;
+
+/**
+ * Group subtasks into dependency levels. Returns array of arrays of ids.
+ * Throws if the graph is unresolvable (should not happen — planner validated).
+ */
+function topologicalLevels(subtasks) {
+  const byId = new Map(subtasks.map((s) => [s.id, s]));
+  const indegree = new Map(subtasks.map((s) => [s.id, 0]));
+  const dependents = new Map(subtasks.map((s) => [s.id, []]));
+
+  for (const s of subtasks) {
+    for (const dep of s.dependsOn) {
+      if (!byId.has(dep)) continue;
+      indegree.set(s.id, indegree.get(s.id) + 1);
+      dependents.get(dep).push(s.id);
+    }
+  }
+
+  const levels = [];
+  let frontier = subtasks.filter((s) => indegree.get(s.id) === 0).map((s) => s.id);
+  const resolved = new Set();
+
+  while (frontier.length > 0) {
+    levels.push(frontier);
+    const next = [];
+    for (const id of frontier) {
+      resolved.add(id);
+      for (const child of dependents.get(id)) {
+        indegree.set(child, indegree.get(child) - 1);
+        if (indegree.get(child) === 0) next.push(child);
+      }
+    }
+    frontier = next;
+  }
+
+  if (resolved.size !== subtasks.length) {
+    throw new Error("Unresolvable subtask graph (cycle or dangling dependency)");
+  }
+  return levels;
+}
+
+function compressResult(text) {
+  if (typeof text !== "string") return String(text ?? "");
+  if (text.length <= MAX_CONTEXT_CHARS) return text;
+  return text.slice(0, MAX_CONTEXT_CHARS) + "\n…[truncated]";
+}
+
+function buildContextForSubtask(subtask, resultsById) {
+  if (!subtask.dependsOn || subtask.dependsOn.length === 0) return null;
+  const parts = [];
+  for (const dep of subtask.dependsOn) {
+    const r = resultsById.get(dep);
+    if (r && r.success && r.result) {
+      parts.push(`Result of subtask ${dep}:\n${compressResult(r.result)}`);
+    } else if (r) {
+      parts.push(`Subtask ${dep} did not complete successfully.`);
+    }
+  }
+  return parts.length > 0 ? parts.join("\n\n") : null;
+}
+
+/**
+ * Dispatch a validated plan.
+ * @param {Object} plan - { subtasks: [...] }
+ * @param {Object} [options]
+ * @param {string} [options.sessionId]
+ * @param {string} [options.cwd]
+ * @param {Function} [options.spawnParallel] - (agentTypes[], prompts[], opts) => results[]
+ * @returns {Promise<{results: Array, levels: Array, stats: Object}>}
+ */
+async function dispatchPlan(plan, options = {}) {
+  const spawnParallel = options.spawnParallel || require("../index").spawnParallel;
+  const subtasks = plan.subtasks;
+  const byId = new Map(subtasks.map((s) => [s.id, s]));
+  const levels = topologicalLevels(subtasks);
+  const resultsById = new Map();
+
+  let totalInputTokens = 0;
+  let totalOutputTokens = 0;
+  let totalSubagents = 0;
+
+  for (let li = 0; li < levels.length; li++) {
+    const levelIds = levels[li];
+    const levelSubtasks = levelIds.map((id) => byId.get(id));
+
+    const agentTypes = levelSubtasks.map((s) => s.agentType);
+    const prompts = levelSubtasks.map((s) => s.prompt);
+    const perTaskContext = levelSubtasks.map((s) => buildContextForSubtask(s, resultsById));
+
+    logger.info(
+      { level: li, count: levelIds.length, ids: levelIds },
+      "[Decomposition] Dispatching subtask level"
+    );
+
+    // spawnParallel shares one options object; pass per-task context by spawning
+    // the level as individual parallel calls when contexts differ.
+    const levelResults = await runLevel(
+      spawnParallel,
+      agentTypes,
+      prompts,
+      perTaskContext,
+      options
+    );
+
+    levelResults.forEach((res, idx) => {
+      const st = levelSubtasks[idx];
+      totalSubagents += 1;
+      totalInputTokens += res?.stats?.inputTokens || 0;
+      totalOutputTokens += res?.stats?.outputTokens || 0;
+      resultsById.set(st.id, {
+        id: st.id,
+        agentType: st.agentType,
+        success: !!res?.success,
+        result: res?.success ? res.result : null,
+        error: res?.success ? null : res?.error || "unknown error",
+        stats: res?.stats || {},
+      });
+    });
+  }
+
+  const results = subtasks.map((s) => resultsById.get(s.id));
+  return {
+    results,
+    levels,
+    stats: {
+      subagents: totalSubagents,
+      inputTokens: totalInputTokens,
+      outputTokens: totalOutputTokens,
+    },
+  };
+}
+
+/**
+ * Run one level. When subtasks in the level have differing injected contexts we
+ * spawn them as separate parallel calls (each with its own mainContext), then
+ * await all. When none need context, a single spawnParallel batch is used.
+ */
+async function runLevel(spawnParallel, agentTypes, prompts, perTaskContext, options) {
+  const anyContext = perTaskContext.some((c) => c);
+
+  if (!anyContext) {
+    return spawnParallel(agentTypes, prompts, {
+      sessionId: options.sessionId,
+      cwd: options.cwd,
+    });
+  }
+
+  // Mixed/with-context: one spawnParallel call per subtask so each gets its own
+  // mainContext, executed concurrently.
+  const calls = agentTypes.map((type, i) =>
+    spawnParallel([type], [prompts[i]], {
+      sessionId: options.sessionId,
+      cwd: options.cwd,
+      mainContext: perTaskContext[i] ? { relevant_context: perTaskContext[i] } : undefined,
+    }).then((arr) => arr[0])
+  );
+  return Promise.all(calls);
+}
+
+module.exports = {
+  dispatchPlan,
+  topologicalLevels,
+  buildContextForSubtask,
+  compressResult,
+  MAX_CONTEXT_CHARS,
+};

src/agents/decomposition/gate.js

@@ -0,0 +1,136 @@
+/**
+ * Decomposition gate (Phase 1).
+ *
+ * Decides whether breaking a task into isolated-context subtasks is actually
+ * worth it. This is the make-or-break of the feature: naive "decompose
+ * everything" loses money, because every subagent carries fixed overhead
+ * (planning + per-agent handoff/summarisation). Decomposition only pays off
+ * when the task is (a) genuinely complex, (b) large enough to amortise that
+ * overhead, and (c) divisible into reasonably independent units.
+ *
+ * Pure and synchronous so it can be unit-tested without a model. The caller
+ * supplies a pre-computed complexity `analysis` (from routing/complexity-analyzer)
+ * and the raw payload.
+ */
+
+const DEFAULTS = {
+  minComplexity: 60, // 0-100; only decompose genuinely complex work
+  minTokens: 3000, // estimated monolithic tokens; below this the overhead wins
+  minIndependentUnits: 2, // need at least 2 separable pieces to bother
+  maxSubtasks: 6,
+};
+
+const ENUMERATION_RE = /^\s*(?:[-*+]|\d+[.)]|step\s+\d+\b)/gim;
+const CONJUNCTION_RE = /\b(?:and then|then|also|additionally|as well as|after that|finally|next,)\b/gi;
+const IMPERATIVE_RE = /\b(?:add|create|build|implement|write|refactor|update|fix|remove|delete|migrate|test|document|configure|set up|wire|integrate|generate)\b/gi;
+const FILE_PATH_RE = /\b[\w./-]+\.(?:js|ts|tsx|jsx|py|go|rs|java|rb|c|cpp|h|json|yaml|yml|md|sql|sh|css|html)\b/gi;
+
+function _uniqueMatches(text, re) {
+  const set = new Set();
+  const matches = text.match(re) || [];
+  for (const m of matches) set.add(m.toLowerCase().trim());
+  return set;
+}
+
+/**
+ * Heuristically estimate how many independent units a task contains.
+ * Conservative: takes the strongest of several weak signals rather than summing
+ * them, so a single rambling sentence doesn't look like five subtasks.
+ * @param {string} text
+ * @returns {number}
+ */
+function estimateIndependentUnits(text) {
+  if (!text || typeof text !== "string") return 1;
+
+  const enumerated = (text.match(ENUMERATION_RE) || []).length;
+  const conjunctions = (text.match(CONJUNCTION_RE) || []).length;
+  const imperatives = _uniqueMatches(text, IMPERATIVE_RE).size;
+  const files = _uniqueMatches(text, FILE_PATH_RE).size;
+
+  // Each signal is an independent lower-bound estimate of separable units.
+  const signals = [
+    enumerated, // explicit list items
+    conjunctions + 1, // "do A and then B" → 2 units
+    imperatives, // distinct action verbs
+    files, // distinct files usually map to distinct work
+  ];
+
+  const estimate = Math.max(...signals, 1);
+  return estimate;
+}
+
+/**
+ * Decide whether to decompose.
+ * @param {Object} analysis - result of analyzeComplexity(payload)
+ * @param {Object} payload - the request payload
+ * @param {Object} [options]
+ * @param {Object} [options.config] - threshold overrides (see DEFAULTS)
+ * @param {string} [options.riskLevel] - 'low'|'medium'|'high'; 'high' disables decomposition
+ * @param {string} [options.taskText] - explicit task text (else derived from analysis/payload)
+ * @returns {{ decompose: boolean, reason: string, signals: Object }}
+ */
+function shouldDecompose(analysis, payload = {}, options = {}) {
+  const cfg = { ...DEFAULTS, ...(options.config || {}) };
+
+  const score = Number(analysis?.score ?? 0);
+  const estimatedTokens = Number(
+    analysis?.breakdown?.tokens?.estimated ?? options.estimatedTokens ?? 0
+  );
+
+  const taskText =
+    options.taskText ||
+    analysis?.content ||
+    _firstUserText(payload) ||
+    "";
+
+  const independentUnits = estimateIndependentUnits(taskText);
+
+  const signals = {
+    score,
+    estimatedTokens,
+    independentUnits,
+    riskLevel: options.riskLevel || "low",
+    thresholds: cfg,
+  };
+
+  // Never decompose high-risk work — keep it in one capable context where the
+  // exempt-from-laziness concerns (validation/security) stay coherent.
+  if (options.riskLevel === "high") {
+    return { decompose: false, reason: "high_risk_skip", signals };
+  }
+
+  if (score < cfg.minComplexity) {
+    return { decompose: false, reason: "below_complexity_threshold", signals };
+  }
+
+  if (estimatedTokens < cfg.minTokens) {
+    return { decompose: false, reason: "too_small_to_amortise_overhead", signals };
+  }
+
+  if (independentUnits < cfg.minIndependentUnits) {
+    return { decompose: false, reason: "not_divisible", signals };
+  }
+
+  return { decompose: true, reason: "decompose_worthwhile", signals };
+}
+
+function _firstUserText(payload) {
+  const messages = payload?.messages;
+  if (!Array.isArray(messages)) return "";
+  const user = [...messages].reverse().find((m) => m.role === "user");
+  if (!user) return "";
+  if (typeof user.content === "string") return user.content;
+  if (Array.isArray(user.content)) {
+    return user.content
+      .filter((b) => b?.type === "text" || typeof b?.text === "string")
+      .map((b) => b.text || "")
+      .join("\n");
+  }
+  return "";
+}
+
+module.exports = {
+  shouldDecompose,
+  estimateIndependentUnits,
+  DEFAULTS,
+};