Beyond Perfect Teammates: Multi-Agent Collaboration with Unreliable Colleagues

Chen Huang; Yiyang Zhang; Yuhao Wu; Yang Deng; Wenxuan Zhang

cs.AIOct 12, 2026

Beyond Perfect Teammates: Multi-Agent Collaboration with Unreliable Colleagues

Authors: Chen Huang, Yiyang Zhang, Yuhao Wu, Yang Deng, Wenxuan Zhang

Abstract

LLM-based multi-agent collaboration is increasingly used to solve complex tasks by dividing work among specialized agents and integrating complementary expertise. Yet existing systems and evaluations largely rest on an implicit perfect-colleague assumption: collaborators provide correct and complete information and respond promptly to requests. In realistic teamwork, however, collaborators may return information that does not answer the intended question, provide insufficient detail to support a decision, or fail to respond to a request. To separate task-solving competence from the ability to recover an unreliable evidence-gathering process, we introduce the Unreliable Colleagues Benchmark (UnCoBench), which organizes behavioral failures through Misaligned, Incomplete, and Missed settings. The main agent need to verify contextual correctness, diagnose information gap and track unresolved dependencies in order to obtain the correct evidence for solving the task. We also introduce a verifiable and scalable automated generation pipeline that pairs LLM-based scenario generation with executable checks of answer uniqueness and role necessity. Results across ten models show that similar reliable-setting performance can result in different robustness to unreliable evidence. Trace analysis reveals frequent omissions of corrective follow-up, and the recovery behavior involves inefficient waiting and redundant queries. These findings show that robust collaboration requires not only sound reasoning, but also targeted action to diagnose evidence failures, recover relevant information, and integrate it into decisions. Our data and source code are available at https://github.com/iNLP-Lab/UnCoBench.

Figures & tables

Figure 1: Behavior difference between perfect and unreliable colleagues in multi-agent collaboration.

Figure 2: Construction pipeline for UnCoBench . The first three steps produce structured specifications, logically verified instances, and validated natural-language tasks, establishing the Reliable baseline. The final step then derives three paired unreliable settings.

	Reliable		Misaligned		Incomplete		Missed
Main agent	Acc. (%) $\uparrow$	Rounds $\downarrow$	Acc. (%) $\uparrow$	Rounds $\downarrow$	Acc. (%) $\uparrow$	Rounds $\downarrow$	Acc. (%) $\uparrow$	Rounds $\downarrow$
GPT-5.6 Sol $\dagger$	98.7	2.18	45.8 (-52.9)	3.06 (+0.89)	77.0 (-21.7)	2.93 (+0.76)	97.4 (-1.3)	4.97 (+2.80)
Claude Opus 5 $\dagger$	96.7	2.18	90.7 (-6.0)	3.99 (+1.81)	95.7 (-1.0)	3.11 (+0.94)	95.8 (-0.9)	3.24 (+1.06)
Gemini 3.8 Flash $\dagger$	99.3	2.09	74.1 (-25.2)	3.58 (+1.49)	88.5 (-10.8)	2.91 (+0.82)	99.1 (-0.2)	3.09 (+1.00)
DeepSeek-V4.1-Flash $\ddagger$	92.6	2.10	14.5 (-78.1)	2.50 (+0.40)	73.8 (-18.8)	2.71 (+0.62)	89.3 (-3.3)	3.16 (+1.07)
GLM-5.3-Flash $\ddagger$	97.4	2.30	35.1 (-62.3)	3.19 (+0.89)	87.8 (-9.6)	3.05 (+0.75)	96.2 (-1.2)	3.61 (+1.31)

Table 1: Main results on UnCoBench .

\dagger

and

\ddagger

denote closed-source and open-weight models respectively. Colored deltas indicate changes from the Reliable setting: red for accuracy, measured in percentage points, and blue for mean interaction rounds.

Figure 3: Reliable to unreliable joint correctness transitions, separated by unreliable setting. Each row partitions all task pairs into four observed outcome transitions.

Figure 4: Behavioral pathways under the Misaligned and Incomplete settings. Each category describes how models respond across tasks and does not directly indicate changes in accuracy.

Figure 5: Behavioral decomposition of extra rounds in Missed relative to Reliable . Left: contribution of each observable behavior to the mean round difference. Right: distribution of the number of later contacts with the designated missed role.

Figure 6: Accuracy and mean rounds across communication settings for the six models shown under Mixed . Error bars denote Wilson 95% confidence intervals for accuracy.

Appendix figures & tables9 assets

Supplementary material from the paper’s appendix.

Appendix

Reference scenario	Description and decision suggestion
Evacuation and shelter	Coordinate evacuation and accommodation with distributed risk and resource information. Decision: Choose evacuation destinations, shelters or safe accommodation plans.
Transport and emergency rescue	Coordinate capacity, access, receiving requirements and timing for transport or rescue. Decision: Choose routes, destinations, rescue plans or supply delivery plans.
Events and venue selection	Combine participant needs, venue conditions and organizational resources. Decision: Choose venues, event arrangements or feasible relocation plans.
Research and field operations	Combine research needs, facility capabilities and environmental information. Decision: Choose field camps, research facilities, equipment locations or work plans.
Asset protection and disaster recovery	Coordinate preservation, transfer and recovery of physical or digital assets. Decision: Choose storage sites, transfer plans, backup facilities or recovery arrangements.
Investigation, localization and cause identification	Combine distributed records and observations to check explanations, targets or investigation plans. Decision: Evaluate explanations, locate targets or select investigation arrangements.

Appendix

Table 2: Scenario references supplied to the task generator.

Operation	Calculation	Constraints
Sum	$\sum_{i=1}^{m}x_{i}$	Operands and result share a unit.
Difference	$x_{1}-x_{2}$	Exactly two operands, with the same unit.
Average	$\frac{1}{m}\sum_{i=1}^{m}x_{i}$	Equally weighted observations with the same unit and basis.
Ratio	$x_{1}/x_{2}$	Exactly two operands; the denominator domain excludes zero. No multiplication by 100.
Product	$\prod_{i=1}^{m}x_{i}$	Result dimensions equal the product of operand dimensions.
Weighted sum	$\sum_{i=1}^{m}w_{i}x_{i}$	Positive dimensionless weights; no normalization by their sum.

Appendix

Table 3: Numerical operation references.

Figure 7: Distribution of the 1,000 task groups across the 14 application domains.

Operation	Form	Groups	Share (%)
Sum	$x_{1}+x_{2}$	131	13.1
Difference	$x_{1}-x_{2}$	137	13.7
Arithmetic mean	$\sum_{i=1}^{n}x_{i}/n$	122	12.2
Ratio	$x_{1}/x_{2}$	113	11.3
Product	$x_{1}x_{2}$	125	12.5
Weighted sum	$\sum_{i}w_{i}x_{i}$	138	13.8

Appendix

Table 4: Numerical-rule diversity across the 1,000 task groups.

Validation stage	Passed / Base	Rejected	Pass rate (%)
Specification validation	1,289 / 1,296	7	99.46
Logical compilation	1,282 / 1,289	7	99.46
Full-information acceptance	1,000 / 1,282	282	78.00
Overall	1,000 / 1,296	296	77.16

Appendix

Table 5: Candidate filtering in the automated construction pipeline.

Validation stage	Automated accepted	Automated rejected	Human accepted	Human rejected	Agreement (%)
Specification validation	98	2	100	0	98
Logical compilation	98	2	98	2	100
Full-information acceptance	85	15	92	8	93

Appendix

Table 6: Comparison of automated and human validation on 100 candidates per stage.

Main agent	DS-V4-Flash-0731		GPT-5.6 Sol		Qwen3.7-Flash
Main agent	Fidelity (%)	Coverage (%)	Fidelity (%)	Coverage (%)	Fidelity (%)	Coverage (%)
GPT-5.6 Sol	99.50	97.33	100.00	99.62	99.00	98.38
Claude Opus 5	99.75	98.66	100.00	99.75	98.50	97.67
Gemini 3.8 Flash	99.50	98.40	99.75	99.52	98.75	97.25
DeepSeek-V4.1-Flash	99.25	98.73	100.00	99.60	99.00	97.33
GLM-5.3-Flash	98.50	95.80	99.50	98.93	98.25	95.05

Appendix

Table 7: Role agent comparison across main agent models.

Arm	Information supplied	Capabilities still required
None	No additional information is supplied.	Recognize the need for recovery; localize and diagnose the problem; formulate and execute a repair; integrate the recovered evidence.
Existence	One prior collaborator interaction is identified as requiring recovery, without specifying which interaction or why.	Localize and diagnose the problem; formulate and execute a repair; integrate the recovered evidence.
Localization	Interaction $i$ with Role $R$ is identified as requiring recovery, without specifying the defect.	Diagnose the problem; formulate and execute a repair; integrate the recovered evidence.
Diagnosis	The concrete communication problem $P$ in the localized interaction is specified.	Translate the diagnosis into a corrective action; execute the repair; revise the reasoning; integrate the recovered evidence.
Action	Problem $P$ is specified and the model is instructed to perform corrective action $X$ .	Execute the instruction; process new evidence; revise the reasoning; produce the final answer.

Appendix

Table 8: Nested intervention arms for diagnosing communication-recovery bottlenecks. Role

R

, interaction

i

, problem

P

, and corrective action

X

are instantiated from the corresponding task and trajectory.

Figure 8: Joint correctness under progressively more informative interventions across the three unreliable settings.

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