HEAD-TO-HEAD BENCHMARK COMPARISONTier 1 vs Tier 1

Gemini 3.1 Pro Preview vs OpenAI GPT-5

Empirical evaluation across autonomous coding benchmarks (SWE-bench Verified, LiveCodeBench), token economics, and multi-agent topology in Swarm.

TECHNICAL VERDICT

For autonomous agentic coding where multi-file patch pass rate is paramount, Gemini 3.1 Pro Preview holds the verified advantage (+1.5% advantage). Both models share identical input pricing at $2.5/M. In Swarm multi-agent clusters, Both models sit in Tier 1 (Tier 1: Frontier Large-Context Architect). Excellent peer redundancy or parallel Coder swarm execution.

Gemini 3.1 Pro Preview

Primary / Planner
SWE-bench Verified:71%
LiveCodeBench:62.4%
Pricing (In / Out):$2.5 / $10
VS

OpenAI GPT-5

Primary / Planner
SWE-bench Verified:69.5%
LiveCodeBench:74%
Pricing (In / Out):$2.5 / $10

Standardized Coding & Reasoning Benchmarks

Verified, contamination-free benchmark scores with direct mathematical deltas.

Benchmark MetricGemini 3.1 Pro PreviewOpenAI GPT-5Performance Delta
SWE-bench VerifiedReal-world GitHub issues resolved autonomously71%69.5%Gemini 3.1 Pro Preview (+1.5% advantage)
LiveCodeBenchPost-training cutoff algorithmic challenges62.4%74%OpenAI GPT-5 (-11.6% difference)
LMSYS Coding EloCrowdsourced blind developer preference13951418OpenAI GPT-5 (-23Elo difference)
AIME (Competition Math)Deep multi-step deductive reasoning86.5%91.2%OpenAI GPT-5 (-4.7% difference)

Token Economics & Operational Cost Ratio

Pricing per 1M tokens and prompt caching advantages for long-horizon sessions.

Prompt Input Tokens
Gemini 3.1 Pro Preview$2.5 / 1M
OpenAI GPT-5$2.5 / 1M

Both models share identical input pricing at $2.5/M.

Completion Output Tokens
Gemini 3.1 Pro Preview$10 / 1M
OpenAI GPT-5$10 / 1M

Both models share identical completion pricing.

Context Caching Advantage
Gemini 3.1 Pro Preview$$0.35 / 1M
OpenAI GPT-5$$0.6 / 1M

Prompt caching significantly reduces long-horizon AST parsing costs during multi-turn Swarm pairing sessions.

Swarm Multi-Agent Topology Synergy

How Swarm orchestrates Gemini 3.1 Pro Preview and OpenAI GPT-5 in autonomous engineering clusters.

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Optimal Cluster Configuration

Both models sit in Tier 1 (Tier 1: Frontier Large-Context Architect). Excellent peer redundancy or parallel Coder swarm execution.

Tier 1

Gemini 3.1 Pro Preview

Supreme context window capacity allows analyzing multi-package architecture and drafting complex Task Program DAGs.

Worktree Isolation: Supervises worktree integrations and validates commit diffs before merging.
Tier 1

OpenAI GPT-5

High-confidence planning eliminates hallucinated stages and coordinates complex multi-worker Task Programs effortlessly.

Worktree Isolation: Supervises parallel Git worktrees and verifies build assertions before promoting code to dev.

When to Choose Which Model

Practical developer recommendations based on real-world engineering workloads.

Choose Gemini 3.1 Pro Preview if:

  • ✓Improved tool calling stability over 2.5 Pro
  • ✓Lower first-token latency on large context prompts
  • ✓Enhanced algorithmic accuracy on LiveCodeBench (42.8%)
  • ✓Need Primary / Planner specialization inside Swarm.

Choose OpenAI GPT-5 if:

  • ✓69.5% on SWE-bench Verified with zero configuration overhead
  • ✓Crisp, concise code explanations without unnecessary boilerplate
  • ✓Native integration with modern developer toolchains
  • ✓Need Primary / Planner specialization inside Swarm.

Frequently Asked Comparison Questions

Which model is better for autonomous software engineering: Gemini 3.1 Pro Preview or OpenAI GPT-5?

For autonomous agentic coding where multi-file patch pass rate is paramount, Gemini 3.1 Pro Preview holds the verified advantage (+1.5% advantage). Both models share identical input pricing at $2.5/M. In Swarm multi-agent clusters, Both models sit in Tier 1 (Tier 1: Frontier Large-Context Architect). Excellent peer redundancy or parallel Coder swarm execution. On SWE-bench Verified, Gemini 3.1 Pro Preview scores 71% vs OpenAI GPT-5 at 69.5%.

How do Gemini 3.1 Pro Preview and OpenAI GPT-5 compare on token pricing and operational economics?

Both models share identical input pricing at $2.5/M. On cached prompts, Gemini 3.1 Pro Preview costs $0.35/M vs OpenAI GPT-5 at $0.6/M.

How does Swarm configure Gemini 3.1 Pro Preview and OpenAI GPT-5 in multi-agent workflows?

Both models sit in Tier 1 (Tier 1: Frontier Large-Context Architect). Excellent peer redundancy or parallel Coder swarm execution. Swarm isolates code modifications in independent Git worktrees, allowing both models to operate in parallel without colliding working directories or git branch conflicts.

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