| One central orchestrator reads everything, decides everything | Centralized information structure used where decentralized partition is cheaper and equally optimal under Radner conditions | Apply #2 + #5: if the team is LQG-like and observations are local, a decentralized linear rule matches centralized payoff at lower cost |
| Each subagent given full system context "just in case" | Information cost (#7) ignored; redundant observations dominate token budget | Partition observations to what each agent's action depends on; redundancy must justify itself |
| Local optimization per subagent declared "team-optimal" | Person-by-person optimality (#3) confused with team optimum; PBPO is necessary, not sufficient | Verify joint optimum by varying any two policies simultaneously, not one at a time |
| "Add a comms channel between agents" added without payoff analysis | Value of communication (#4) not computed; channel may cost more than it earns | Compute expected payoff with vs. without the channel; if delta < cost, drop it |
| "Multi-agent by default for complex tasks" | Coordination overhead costs are O(N²) in token accumulation; DPI shows message routing loses conditioning information available in unified context | Default to single-agent for sequential reasoning tasks; require empirical evidence that parallelization actually helps before adding agents (Tran & Kiela 2026) |
| "Assume natural-language inter-agent messages are lossless" | Natural-language agent-to-agent messages are lossy compressions; semantic drift accumulates across rounds even with no explicit error (Rath 2026); embedding-space exchange is lossless at lower token cost (LatentMAS, ICML 2026 Spotlight) | For high-precision cooperative tasks, route inter-agent signals through shared latent representations rather than text (primitive #2 information structure design) |
| "Default to all-to-all communication between agents" | Dense topologies amplify error propagation in LLM multi-agent systems (Shen et al. 2025); moderately sparse topologies outperform both fully dense and fully sparse | Design inter-agent communication graphs at moderate sparsity; use adaptive topology if task structure changes dynamically (CARD, ICLR 2026) |
| "Put the expert on the team and the team will use them" | Aggregation rule, not expertise identification, is the binding constraint. Self-organizing LLM teams underperform their own strongest member by up to 41.1% because they converge on integrative compromise — averaging expert and non-expert views instead of weighting by competence — and the gap widens with team size (Pappu et al., ICML 2026). Teams identify the expert correctly and still fail to defer | Make deference explicit rather than emergent: route the decision to the competent agent instead of pooling opinions, or weight contributions by a verifiable competence signal. Note the tradeoff — the same consensus-seeking that suppresses expertise also buffers against adversarial members, so keep pooling where robustness matters more than peak accuracy |
| Assume linear/affine policies optimal in non-LQG team | Witsenhausen (#6) shows nonlinear policies can dominate when signaling exists | Check if any agent's action affects another agent's observation; if yes, allow nonlinear policies |
| Treat all multi-agent setups as game-theoretic | Common-task condition (#10) holds — agents share a goal — so mechanism-design overhead is wasted | Skip incentive compatibility; design for joint optimization directly |
| Treat all multi-agent setups as team problems | Common-task condition (#10) fails — agents have divergent goals — team theory underestimates conflict | Switch to game theory (auctions, mechanism design) |
| "Optimize the team's collective intelligence (c-factor)" (human teams) | The single-factor c-factor (Woolley et al. 2010) is weaker than its popular reception implies. Meta-analysis puts its correlation with external group performance at r=.26, and all but four of the pooled studies failed to control for members' individual intelligence (Rowe, Hattie & Hester 2021); Rowe, Hattie & Munro (2024, PLOS ONE) favor a two-factor (fluid/crystallized) structure over a unified c. Earlier non-replications exist for virtual text-based groups | Do not treat "collective intelligence" as a single tunable team property. Select on task-relevant individual competence and the information structure (#2) first; treat composition heuristics from this literature as hypotheses to test locally, not established effects |
| "Psychological safety assumed universally positive" (human teams) | Curvilinear boundary condition (Edmondson & Bransby 2023, Annual Review of OB, citing Eldor, Hodor & Cappelli 2023): high psychological safety may harm routine in-role performance by redirecting attention to exploration; benefit is robust for learning/adaptive tasks only; accountability structures moderate the downside. The curvilinear result rests on one five-study paper with no independent replication as of August 2026 — treat as a boundary condition worth testing, not settled. Also commonly conflated with comfort/niceness — see patterns-scenarios-traps.md for misreads | Apply psychological safety practices to adaptive/learning contexts; pair with accountability norms for routine-execution tasks; do not assume monotonic benefit; don't mistake candor-friendly for conflict-free |
| Hierarchical orchestrator-worker with no information flow back up | Polyarchy/hierarchy structure (#8) chosen by default; loses bottom-up signal that decentralized form preserves | Add upward observation channel or switch to decentralized form; for tasks with parallelizable subtasks at scale (>4 agents), consider emergent self-organization protocols where agents self-assign roles — this form dominates fixed hierarchy at scale (Dochkina 2026) |
| "Just add more agents/people, coordination scales for free" | Team-size/coordination-cost curve (#8b): pairwise coordination channels grow ~n(n-1)/2 with team size under high coupling; the marginal member's coordination cost can exceed their contribution (Brooks's Law) | Before adding a member/agent, count how many existing members it must (not could) coordinate with; if most, cut coupling first (modularize, assign a single owner for shared state) rather than adding capacity |
| "We are a centralized [org/agent system]" or "we are a decentralized one" applied blanket-wide | Centralize-vs-decentralize is a per-decision judgment (#8a: information compressibility, reversibility, coupling, blast radius of a wrong local call), not a company-wide or system-wide constant | Apply the four-question test per decision class; expect most real orgs and agent systems to be centralized on some decisions (shared state, brand, safety) and decentralized on others (local execution) |