ENGINEERING STUDY

Tool Calling Is an Infrastructure Problem Too

Identical models disagree on tools depending on who serves them.

Key findings
  • Qwen3-235B tool success spans 94.7%–99.2% (4.5 points) across 12 providers under the Agents workload.
  • Llama 3.3 70B shows the same pattern: a 4.7-point spread on identical weights.
  • At agent chain lengths of 10+ calls, the per-call gap compounds into materially different task-completion rates.

Same weights, different agents

A 2-point per-call difference sounds small. Across a 10-call agent chain it is the difference between an 82% and a 90% chance of a flawless run — visible directly in production error budgets.

Fireworks99.2OpenRouter99.0Cerebras98.8Nebius98.1Groq97.5Together96.9Nextbit96.7Scaleway96.6DeepInfra95.7Mistral95.7SiliconFlow95.2OVHcloud94.7
Tool-call success by provider · Agents workload · DEV DATA
What this means for engineers
  • Agent teams should benchmark tool success per provider, not per model, and re-verify after provider-side serving updates.
Dataset

Published figures are pinned to this snapshot and are not recalculated retrospectively. View the current benchmark →

Cite this researchInferenceBench (2026). Tool Calling Is an Infrastructure Problem Too. InferenceBench Research.
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