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Research · Aug 22, 2026, 06:36 AM · 4 sources

GLM-5.3 + GPT-5.6 Sol cascade: 85.9% solve rate, 21% cheaper than Sol alone

<cite index="43-2">On DeepSWE v1.1, GPT-5.6 Sol leads single-shot at 72.7% pass@1 versus GLM-5.3's 69.0%, but GLM-5.3 reverses the order on retries: 81.1% pass@2 (tying Sol's 81.0%) and 87.6% pass@4 (beating Sol's 85.8%).</cite> <cite index="43-2">The key advantage: cascading GLM-5.3 first then escalating to Sol for failures solves 85.9% of tasks at $6.61 per task—13 points better than Sol alone at 72.7%, yet 21% cheaper than Solo solo at $8.37.</cite>

<cite index="43-2">Sol wins on latency and reliability: 19 minutes and 61 steps per rollout versus GLM's 35 minutes and 124 steps.</cite> <cite index="43-2">Sol's reliability stands at 84.5% with 61 tasks solved four-for-four, while GLM-5.3 trades reliability for broader coverage at 87.6% pass@4 but lower per-attempt consistency (78.8%).</cite> <cite index="43-2">GLM-5.3's failure mode is safer: it breaks existing tests in 11% of failures versus Sol's 20%.</cite>

For production routing: <cite index="43-2">the two models diverge sharply (0.43 per-task correlation) yet together cover 106 of 113 tasks (93.8%), making them ideal complements in a cascade.</cite> Domain split is clean—Sol dominates data modeling, serialization, ops tooling, and protocol work; GLM-5.3 excels at query languages, runtime internals, and reactivity. <cite index="43-2">GLM-5.3's standout is JavaScript at 90% (15 points ahead of Sol); Sol answers with Python, Go, and TypeScript strength.</cite> The engineering lesson: optimal coding agent cost is not a single model but a routing strategy.

Sources

Everything this brief rests on
  1. 01 Primary source together.ai
  2. 02 together.ai together.ai “Run GLM-5.3 first, escalate to GPT-5.6 Sol when the tests fail. That cascade solves 85.9% of DeepSWE tasks at $6.61 each. Sol alone solves 72.7% at $8.37. Thirteen points better, 21% cheaper”
  3. 03 together.ai together.ai “At $3.99 a rollout, GLM-5.3 is 2.1x cheaper than Sol ($8.37), which in value terms is 17 solves per $100 against Sol's 9”
  4. 04 together.ai together.ai “Per-task correlation is 0.43, real disagreement for two models this close on aggregate. They both solve 90 tasks; GLM-5.3 alone gets 9, Sol alone gets 7, and 7 defeat both. Their union covers 106 of 113 tasks (93.8%)”