Large language model (LLM) agents are increasingly used in trading systems, where model reasoning, tool use, and continual decisions incur costs that are expected to produce trading value. Existing evaluations typically report performance metrics, but rarely examine agentic viability: whether dynamic LLM-mediated decisions convert their induced costs into measurable incremental profit. To apply this criterion, we introduce TradeLens, a trace-grounded diagnostic toolkit for evaluating agentic trading systems from their trading records, runtime traces, and deployment configurations. It reconstructs trading trajectories, attributes profit and cost to interpretable evidence, and diagnoses whether and why an agent pays for its own intelligence. We conduct extensive analysis across backbone models, capital scales, trading frequencies, and system architectures, together with deployment discussion. Our results show that viability hinges on intelligence-to-profit conversion: models exhibit different failure patterns, such as poor asset selection in DeepSeek-V3.2 and negative timing in GLM-4.7, while capital scale, trading frequency, and architecture matter primarily in these runs, especially through their effects on decision-attributed timing value. These findings reframe the evaluation of LLM-based trading agents from capability-centric performance ranking to trace-grounded diagnosis of intelligence-to-profit conversion. Our code is available at https://github.com/ParadooxAI/TradeLens.

Large language models (LLMs) are increasingly used to explain numerical time series, but fluent explanations can misstate when a change occurs, overstate a trend, or introduce unsupported patterns. Existing evaluations often score forecasts, answers, or whole explanations, leaving claim-level temporal grounding undermeasured. We introduce TimeClaimBench, a benchmark that parses explanations into atomic temporal claims and verifies them against a deterministic extracted event graph. Across five LLMs on controlled synthetic series, event-grounded prompting raises the strict graph-supported rate by 18.3 points and reduces graph-unsupported claims by 27.9 points under this fixed operational criterion. Calibration analyses show the boundary of that result. The extractor recovers the designed primary event in 394 of 400 series, but this does not estimate the precision of additional extracted events. A blinded two-annotator comparison on one model and 40 series reverses the automatic ordering: holistic ratings favor Direct and chain-of-thought outputs over event-grounded outputs. therefore distinguishes four axes that should not be conflated: designed-event recovery, the unresolved precision of additional events, claim-to-graph consistency, and whole-explanation human judgment. Code: https://github.com/lunaaa95/TimeClaimBench