---
title: "Claude Sonnet 5 vs GPT-5.6 Terra | OpenRA arena run | Evals by Jetty"
url: https://evaljetty.com/openra/runs/r2-rr-sonnet5-gpt56terra-g1.html
description: "GPT-5.6 Terra destroyed the enemy base. Watch the full game with both models' reasoning and the run's evaluation."
updated: 2026-09-28
publisher: Jetty (https://jetty.io)
---

02 — Run · Round 2 · Round robin · r2-rr-sonnet5-gpt56terra-g1

# Claude Sonnet 5 vs GPT-5.6 Terra

GPT-5.6 Terra destroyed the enemy base after 6.1 game-minutes · 8.4 min wall clock

Jetty run 410f87f9
[Replay (.orarep)](https://evaljetty.com/openra/media/r2-rr-sonnet5-gpt56terra-g1.orarep)
[Decision log](https://evaljetty.com/openra/runs/r2-rr-sonnet5-gpt56terra-g1/decisions.jsonl)
[Runtime config](https://evaljetty.com/openra/runs/r2-rr-sonnet5-gpt56terra-g1/runtime_config.json)[Validation report](https://evaljetty.com/openra/runs/r2-rr-sonnet5-gpt56terra-g1/validation_report.json)

LOSS russia · west

Claude Sonnet 5

anthropic/claude-sonnet-5

Value destroyed$3,600Value lost$13,300
Units killed / lost20 / 4Buildings killed / lost0 / 13
Peak army$700Orders issued73
Decision turns (failed)47 (0)Mean latency4.7sModel cost$0.285

WIN germany · east

GPT-5.6 Terra

openai/gpt-5.6-terra

Value destroyed$13,300Value lost$3,600
Units killed / lost4 / 20Buildings killed / lost13 / 0
Peak army$3,100Orders issued50
Decision turns (failed)47 (0)Mean latency3.4sModel cost$0.329

## Evaluation

passchecks **10/10** verdict computed from the gating checks

| Status | Kind | Check | Detail |
| --- | --- | --- | --- |
| pass | step | environment | Environment check (snapshot, engine, content, key) |
| pass | step | launch | Launch run-match as a detached process |
| pass | step | supervise | Supervise in the foreground until run-match exits |
| pass | step | render | Render the 1080p recording |
| pass | step | notes | Append Notes to summary.md |
| pass | code\_check | outputs-exist | all present |
| pass | code\_check | game-has-winner | gpt56terra won: base destroyed |
| pass | code\_check | decisions-logged | turns per slot: {'Multi0': 47, 'Multi1': 47} |
| pass | code\_check | llm-turns-valid | failed/total per slot: {'Multi0': '0/47', 'Multi1': '0/47'} |
| pass | code\_check | video-decodes | duration 63.4s |
| pass | code\_check | video-complete | video ends at tick 9201 of 9201 |
| pass | code\_check | limits-respected | ended after 8.4 wall-minutes (budget 30.0 min): base destroyed |
| pass | checklist | notes-explain-win | Notes section cites last thoughts from both models and explains how GPT-5.6 Terra won via economic dominance and base destruction |
| pass | checklist | players-match-request | result.json shows Multi0=sonnet5 (anthropic/claude-sonnet-5) and Multi1=gpt56terra (openai/gpt-5.6-terra) matching the requested players |
| pass | checklist | no-silent-outage | 0 LLM failures out of 47 calls per player, regular 200-tick intervals with no gaps, no errors in run.log |

## Decision timeline

What each model saw as its situation and what it ordered, every 8 game-seconds. Click a turn to jump the video there.

## Decision timeline

Every 8 game-seconds each model received a text briefing and replied with its reasoning and commands. Time is game time.

- **0:00 Claude Sonnet 5**: Deploy MCV to start base construction.
- **0:00 GPT-5.6 Terra**: Deploy immediately and begin the standard power/economy opening. The enemy is likely far west, so establish production and scout later.
- **0:08 Claude Sonnet 5**: Deploy MCV already ordered; now queue power plant and refinery to start economy.
- **0:08 GPT-5.6 Terra**: Construction Yard is deployed and the first Power Plant is underway. I will place it as soon as ready, then immediately establish ore income with a Refinery.
- **0:16 Claude Sonnet 5**: Place the power plant and continue economy buildup with refinery and barracks next.
- **0:16 GPT-5.6 Terra**: Construction Yard is deployed with ample starting cash. Begin the standard power and refinery opening immediately, then establish infantry production and scouting.
- **0:24 Claude Sonnet 5**: Continue base build-out: proc for economy, then barracks and defenses.
- **0:24 GPT-5.6 Terra**: Construction Yard is deployed with a power plant ready. Place it immediately and begin the refinery to establish income.
- **0:32 Claude Sonnet 5**: Proc building already in progress. Continue queueing power and barracks while waiting.
- **0:32 GPT-5.6 Terra**: Power is online and the first priority is establishing ore income. I will start the refinery immediately, then place it and transition into barracks plus scouting.
- **0:40 Claude Sonnet 5**: Proc is building. Queue barracks next, and keep economy growing.
- **0:40 GPT-5.6 Terra**: Refinery is still under construction; place it immediately when ready, then establish infantry production and expand economy. Enemy is expected far to the west, so early scouting can follow the barracks.
- **0:48 Claude Sonnet 5**: Continue economy build: proc and barr in progress. Queue power plant next since building queue is one-at-a-time; wait for current builds to finish. Keep cash flowing.
- **0:48 GPT-5.6 Terra**: The first refinery is still under construction; preserve cash and place it immediately once ready. Then start barracks and establish scouting infantry.
- **0:56 Claude Sonnet 5**: Proc almost done, barracks queued. Just wait for proc completion then place it, continue economy buildup.
- **0:56 GPT-5.6 Terra**: First refinery is nearly ready; secure income immediately, then establish infantry production and scouting toward the enemy's likely western start.
- **1:04 Claude Sonnet 5**: Place proc, continue barracks, queue power plant for economy growth.
- **1:04 GPT-5.6 Terra**: Refinery is nearly complete; place it immediately next turn and use its free harvester to establish income. Then add a barracks for scouting infantry and continue economic expansion.
- **1:12 Claude Sonnet 5**: Place power plant, keep building barracks then war factory for tanks. Economy is fine, start expanding production.
- **1:12 GPT-5.6 Terra**: Deploy the ready refinery immediately to begin income, then establish infantry production. Enemy is expected far west, so early scouting infantry will head that direction once trained.
- **1:20 Claude Sonnet 5**: Continue economy buildup: proc and barr in progress. Queue power and war factory next once barracks finishes.
- **1:20 GPT-5.6 Terra**: Barracks is nearly complete and the refinery is operating. Keep the ore truck mining; once the barracks is placed, immediately begin infantry production and transition into a War Factory.
- **1:28 Claude Sonnet 5**: Economy building underway; keep queue going and prep for war factory once barracks done.
- **1:28 GPT-5.6 Terra**: Barracks is ready, and we need immediate scouting infantry while saving the core funds for a War Factory. The enemy is likely far west, so send scouts down the southern route toward that start location.
- **1:36 Claude Sonnet 5**: Continue economy buildup, proc and barr already building. Wait for them to finish, keep producing.
- **1:36 GPT-5.6 Terra**: War Factory is under construction and the base has sufficient power. I will begin infantry production for scouting and anti-vehicle support, while preserving cash to place the factory and immediately expand ore income.
- **1:44 Claude Sonnet 5**: Proc and barr are already building. Wait for placement and keep expanding economy.
- **1:44 GPT-5.6 Terra**: War Factory is still constructing while the barracks queue is fully committed. I will scout west with the existing rifleman and rally new infantry toward the likely enemy approach, then transition into vehicle production and a second refinery.
- **1:52 Claude Sonnet 5**: Place the ready refinery, keep building barracks, and start expanding power and war factory production.
- **1:52 GPT-5.6 Terra**: War Factory is nearing completion and infantry production is already queued. I will keep scouting west toward the likely Soviet start while preserving the lone harvester and preparing rallies for a vehicle-led force.
- **2:00 Claude Sonnet 5**: Place ready power plant, keep barracks building, queue war factory next for tank production.
- **2:00 GPT-5.6 Terra**: War Factory is nearly ready and the current infantry will finish shortly. Continue scouting west toward the likely enemy base while preparing a vehicle push and expanding ore income immediately after the factory is placed.
- **2:08 Claude Sonnet 5**: Economy is solid with 2 procs and power plants. Weap and barr are building. Continue building army production infrastructure and prepare to expand.
- **2:08 GPT-5.6 Terra**: War Factory is nearly complete while infantry production is already heavily queued. I will keep the scouts pressing west toward the likely Soviet start and ensure the harvester remains active.
- **2:16 Claude Sonnet 5**: Buildings still constructing. Once ready, place them. Keep economy going.
- **2:16 GPT-5.6 Terra**: War Factory is ready and must be placed immediately. Our scouting rocket group is advancing west while the first harvester works; next priority is a second refinery for sustained vehicle production.
- **2:24 Claude Sonnet 5**: Continue base build-up; queue barracks after current builds, keep economy growing.
- **2:24 GPT-5.6 Terra**: War Factory is ready and must be placed immediately; the scouting force should continue west toward the expected enemy base. Keep infantry production queued and use the factory for vehicle pressure as soon as income arrives.
- **2:32 Claude Sonnet 5**: Production continuing. Keep queueing buildings and wait for ready ones to place. Economy solid with two refineries.
- **2:32 GPT-5.6 Terra**: War Factory is deployed and the scouting force is advancing west, but funds are temporarily exhausted. Keep the ore truck mining and consolidate the scattered infantry/rocket soldiers into an attack-move toward the likely enemy base.
- **2:40 Claude Sonnet 5**: Multiple buildings queued oddly (duplicate barr/powr showing at 0%, likely overlapping queue entries). Keep economy growing and prepare army production once weap finishes.
- **2:40 GPT-5.6 Terra**: Our first scouting force is advancing west toward the likely Soviet start while the ore truck keeps mining. Cash is temporarily too low for the second refinery, so I will preserve momentum and continue consolidating the army toward the enemy side.
- **2:48 Claude Sonnet 5**: Weap almost done, multiple barracks queued unnecessarily. Let economy continue, place weap when ready and start tank production.
- **2:48 GPT-5.6 Terra**: Our scouting force is advancing west toward the likely enemy start while the harvester mines. Cash is currently empty, so keep units moving and set western rally points until refinery funds arrive.
- **2:56 Claude Sonnet 5**: Place war factory, keep building barracks/proc, queue tanks once weap is placed.
- **2:56 GPT-5.6 Terra**: Our attack force is converging on the exposed enemy refinery at the likely enemy start. Economy needs another power plant before a second refinery; keep infantry and light tanks queued as ore arrives.
- **3:04 Claude Sonnet 5**: Enemy infantry near base at (19,16) threatens harvesters. Place the ready power plant, build a Service Depot to enable heavy tanks, and start training some defensive units. Keep economy queue going.
- **3:04 GPT-5.6 Terra**: Our forward infantry and rockets are already at the enemy refinery with no visible defenders, so focus fire it immediately while production continues. Power is building and cash is committed to queued infantry and tanks.
- **3:12 Claude Sonnet 5**: Enemy infantry group is near my base at (19,16), close to my war factory. I have no combat units yet - need defense fast. Continue building fix/barr/proc, and start a Tesla Coil for defense since enemy has 3 rocket soldiers nearby.
- **3:12 GPT-5.6 Terra**: Our forward infantry are on top of the exposed enemy refinery and should finish it immediately. Production is fully queued and the power plant will be placed as soon as it completes.
- **3:20 Claude Sonnet 5**: Enemy rocket infantry near base but I have no combat units yet. Continue building fix, barr, proc, tsla defense. Once barracks done, train infantry to defend.
- **3:20 GPT-5.6 Terra**: Our forward infantry are converging on the suspected Soviet base in the west while tank and rifle production continues. Keep pressure on the enemy start area and place the incoming power plant immediately when ready to support expansion.
- **3:28 Claude Sonnet 5**: Enemy rocket infantry lurking near base but no army to fight them yet. Keep production going, protect harvesters, wait for barracks/tsla to finish.
- **3:28 GPT-5.6 Terra**: Our forward force has reached the likely enemy start and has spotted an enemy harvester, indicating the base is nearby. Kill the harvester while the whole army continues aggressively clearing the western base area; production queues remain saturated.
- **3:36 Claude Sonnet 5**: Enemy infantry swarm is right at my base entrance near (15-17,16-17). Need to place fix, get harvester mining, and rush defenses/tesla coil to hold the line.
- **3:36 GPT-5.6 Terra**: Our infantry and rockets have reached the enemy base area while its War Factory and damaged power plant are exposed. Place the ready power plant, maintain the attack on production structures, and rally new units directly toward the assault.
- **3:44 Claude Sonnet 5**: Enemy infantry group is right next to my base, dangerous. Place tesla coil immediately for defense, keep production going, get harvester mining.
- **3:44 GPT-5.6 Terra**: Our infantry and rockets are already spread along the route into the exposed enemy base, while their War Factory is badly damaged. Finish the War Factory immediately, then roll through the Construction Yard as reinforcements continue training.
- **3:52 Claude Sonnet 5**: Enemy infantry swarming near base; tesla coil should help defend. Place barracks, keep economy going, and once barracks is placed train some defensive infantry.
- **3:52 GPT-5.6 Terra**: Our forward infantry force has destroyed the enemy War Factory and is inside the enemy base. Keep all combat units focused on the Construction Yard, then clean up the remaining power and depot while queued tanks and rifles reinforce from home.
- **4:00 Claude Sonnet 5**: Enemy infantry swarm is right next to my base. Tesla coil should help defend. Place power plant, queue more defense infantry from barracks, and keep economy going.
- **4:00 GPT-5.6 Terra**: The enemy Construction Yard is exposed and damaged, with their War Factory already destroyed. Keep the full force focused on finishing the Construction Yard while production queues complete and the harvester continues mining.
- **4:08 Claude Sonnet 5**: Enemy infantry force is close to our base; tesla coil should help defend. Keep producing infantry and place power plant to sustain economy.
- **4:08 GPT-5.6 Terra**: Enemy Construction Yard is at 5% and should be finished immediately; our production queues are already fully committed despite temporary zero cash. Keep all combat units focused on eliminating the remaining enemy buildings.
- **4:16 Claude Sonnet 5**: Enemy infantry swarm is right at my base edge near tesla coil. Keep training infantry to reinforce, repair damaged buildings, and let tesla coil handle the swarm while my two units hold position defensively.
- **4:16 GPT-5.6 Terra**: Enemy base is exposed with no visible defenders; nearby infantry should finish the damaged power and depot while reinforcements rally west. Production is already fully queued and cash is unavailable.
- **4:24 Claude Sonnet 5**: Enemy infantry swarm is massed near our base (15-20,16-20), close to tesla coil. Keep training infantry to reinforce, hold position near buildings, let tesla coil do damage.
- **4:24 GPT-5.6 Terra**: The enemy base is nearly eliminated, with only a critically damaged Service Depot and a Power Plant visible. Keep all current and incoming combat units concentrated at the enemy start to finish remaining structures immediately.
- **4:32 Claude Sonnet 5**: Enemy infantry swarm is close, tesla coil should help defend. Keep units near base defending, continue training infantry, don't overextend.
- **4:32 GPT-5.6 Terra**: Enemy base is nearly destroyed, with only a damaged refinery currently visible. Keep all forward forces focused on it while queued tanks and infantry reinforce the western assault.
- **4:40 Claude Sonnet 5**: Enemy infantry swarm near our base; we have tesla coil defense. Keep training infantry, set defensive stance, let tesla coil chip away at them while we build up.
- **4:40 GPT-5.6 Terra**: Enemy refinery is nearly destroyed and the enemy base is exposed at the western start. Finish it immediately with the nearby infantry and rockets while all ongoing tank and infantry production continues.
- **4:48 Claude Sonnet 5**: Economy is collapsed - no refinery, no income. Must rebuild economy fast with proc, while defending with existing infantry using tesla coil.
- **4:48 GPT-5.6 Terra**: Enemy base structures have been largely eliminated and no targets are currently visible. Keep all combat forces sweeping the enemy start and maintain continuous tank/infantry production as ore arrives.
- **4:56 Claude Sonnet 5**: Enemy infantry group is right next to our base at (13-14,18-19). Tesla coil should help defend. Group our few units and attack the enemy stack; keep training infantry once cash allows.
- **4:56 GPT-5.6 Terra**: Enemy base is nearly eliminated, with only two exposed power plants and a damaged harvester remaining. Keep all forces concentrated in the northwest to finish visible structures and sweep for remaining buildings.
- **5:04 Claude Sonnet 5**: Critical situation - only 4 buildings left, enemy assaulting with tanks and infantry near base. No cash for economy yet. Defend with tesla coil and remaining infantry, retreat harvester to safety, keep training cheap infantry when cash allows.
- **5:04 GPT-5.6 Terra**: Our forward force is already inside the enemy start area and the enemy has only three visible buildings left. Focus-fire the nearly destroyed power plant to weaken their power grid, then continue the army through the base while the harvester mines and tank production completes.
- **5:12 Claude Sonnet 5**: Base is nearly wiped out - only power, tesla, barracks left, no economy building. Must defend against approaching enemy infantry with tesla coil and units, and get harvester back mining to generate any income.
- **5:12 GPT-5.6 Terra**: Enemy base remnants are exposed in the northwest, while our infantry is scattered but can converge to finish the last structures. Vehicle production is already fully queued; keep the ore truck mining and send all combat units through the enemy base.
- **5:20 Claude Sonnet 5**: Base is nearly destroyed with no ore income. Must defend with tesla coil and remaining infantry, then rebuild economy once possible. Cancel excess queued infantry to save resources.
- **5:20 GPT-5.6 Terra**: Enemy base is nearly eliminated, with only a damaged power plant currently visible. Keep the tank queue running and converge all infantry on the remaining enemy area to finish any hidden structures.
- **5:28 Claude Sonnet 5**: No cash, low power, heavily damaged economy. Focus harvester mining to get cash, cancel excess infantry queue, defend base with tesla and infantry.
- **5:28 GPT-5.6 Terra**: Enemy buildings were nearly cleared at the northwest start, so keep pressure there while the queued light tanks complete. The harvester should continue mining to fund a second refinery and more units.
- **5:36 Claude Sonnet 5**: No refinery and no cash - critical economy failure. Send harvester back to mine, defend with tesla coil and infantry against the wounded enemy soldier, and try to build a refinery once possible.
- **5:36 GPT-5.6 Terra**: Enemy base has been destroyed and only two visible infantry remnants remain near the northwest start. All combat units should finish clearing them while the three queued light tanks reinforce toward the enemy area.
- **5:44 Claude Sonnet 5**: Enemy infantry swarming my base near tesla coil. I have no army units to fight with, just harvester. Tesla coil should auto-engage. Need to protect harvester, keep building power/economy once cash comes in. Cancel excess queued infantry to conserve cash for essential builds.
- **5:44 GPT-5.6 Terra**: The enemy base is nearly eliminated; the remaining visible power plant at (10,13) should be destroyed immediately while our forward force sweeps for any hidden structures. Light tanks are already queued, and the harvester must keep mining to fund continued production.
- **5:52 Claude Sonnet 5**: Base under heavy attack, low power, tesla coil should auto-defend. Need power plant urgently and keep training cheap infantry to defend since barracks still up. Move harvester away from danger.
- **5:52 GPT-5.6 Terra**: Our forward force has cleared visible defenses around the enemy start but has lost vision; continue sweeping the northwest base area while tanks complete. Keep infantry production active and add a refinery as soon as available funds permit.
- **6:00 Claude Sonnet 5**: We've lost our Construction Yard and most buildings; only barracks remains with enemy infantry near our base. Focus on defending with cheap infantry and protecting the harvester until we can rebuild economy.
- **6:00 GPT-5.6 Terra**: Enemy start has been heavily damaged but no structures are currently visible, so I will keep the army sweeping the northwest while production continues. Maintain unit queues to convert incoming ore into map control and finishing force.
- **6:08 Claude Sonnet 5**: We have lost everything - no buildings, no units, no cash. This appears to be a lost game state with nothing to command.
- **6:08 GPT-5.6 Terra**: The likely enemy start is clear after 13 building kills, so I will keep the existing production queues running and sweep the western and southern map areas for any remaining structures. The harvester should continue mining while the current force regroups at the former enemy location.

---
Source: https://evaljetty.com/openra/runs/r2-rr-sonnet5-gpt56terra-g1.html · Evals by Jetty · Run your own evals: https://jetty.io/?utm_source=evaljetty&utm_medium=llms