
What is SkillOpt?
SkillOpt is a text-space optimizer (Text-Space Optimizer) open-sourced by Microsoft (in collaboration with Shanghai Jiao Tong University, Fudan University, and Tongji University), with the following core focus:
Treat the Agent’s skill documentation (skill.md) as trainable ”external parameters.” Just like training a neural network, use trajectory-driven editing combined with validation-gated updates to automatically iterate toward the optimal skill documentation (best_skill.md) without modifying any model weights.
In a nutshell: No need to change the model—just update the ”instructions”—so the agent gets smarter the more it’s used.
It published a preprint on arXiv on May 26, 2026, released its open-source code on May 22, and achieved first or tied-for-first place across all 52 test cases—comprising 6 major benchmarks × 7 models × 3 execution environments—a milestone hailed by the industry as marking ”the transition of agent skill development from a manual workshop to industrial-scale production.”
Key Features of SkillOpt
- Automated Iterative Optimization: Say goodbye to the tedious cycle of manually revising prompts over and over again. Simply provide a training set and a validation set with standard answers, and SkillOpt will automatically perform the task, analyze the causes of failure, and precisely revise the skill documentation.
- Strict verification and access control mechanisms: Every change made to the skill documentation must pass testing on a separate validation set; the change will only be retained if the score improves; otherwise, it will be rolled back to the previous version. This ensures that the skill will only get better over time, rather than worse.
- Easy Deployment and Visualization: Once the training is complete, you will receive a compact
best_skill.mdWhen deploying, simply inject this file as a system prompt. It also provides a WebUI panel that allows you to monitor iteration progress, view revision history, and compare results in real time. - Support for Multiple Models and Backends: Supports APIs for various mainstream models, including OpenAI, Anthropic, Qwen, and MiniMax, and works across different execution environments (such as direct conversation, Codex CLI, and Claude Code CLI).
SkillOpt’s Core Technology
At the core of SkillOpt is the integration of deep learning training principles into the text domain, resulting in a closed-loop iterative system with a division of labor between two models.
- Dual-Model Collaboration:
- Execution Model: Responsible for performing tasks using the current skill documentation and recording a complete history of the execution and the results.
- Model Optimization: Review the execution history, analyze cases of success and failure, and make precise modifications to the technical documentation using structured add, delete, and update operations.
- A Deep Learning-Style Training Loop: The entire optimization process follows a rigorous iterative cycle:Rollout (Execute Task) → Reflect (Reflect and Analyze) → Aggregate/Select (Aggregate, Filter, and Modify Recommendations) → Update (Update Skills) → Validate (Verify Results).
- Text Learning Rate and Editing Budget: To control the extent of modifications and avoid making too many changes at once that could disrupt the original effective rules, SkillOpt introduces the concept of a “text learning rate” or “editing budget,” which limits the number of modifications to a finite number of steps per iteration.
- Reject Edit Buffer: Proposed changes that are rejected during the validation phase are stored in a buffer as negative feedback to prevent future optimizations from repeating the same mistakes.
- Slow/Yuan Update: At the end of each iteration, a comprehensive review is conducted to ensure that the skill documentation is logically coherent, concise, and efficient, and to identify longer-term patterns.
Use Cases for SkillOpt
| take | Specific Examples | effect |
|---|---|---|
| Complex Search Q&A | SearchQA: Accuracy from 77.7% → 87.3%(+9.61 TP4T) | ✅ |
| Tables/Spreadsheets Tasks | SpreadsheetBench:Soared by nearly 40 percentage points(+39 points) | ✅✅ |
| Interactive Decision-Making | ALFWorld Indoor Text-Based Game | ✅ |
| Document Q&A | OfficeQA: Improved Accuracy 39% | ✅✅ |
| mathematical reasoning | Solving Math Problems | ✅ |
| Cross-Project Task Migration | Tasks such as knowledge base management, API calls, and webhook handling that require project experience | Significantly improve stability |
| Coding Agent Skill Optimization | For use with Cursor / Claude Code / Copilot | ✅ |
SkillOpt's project URL
- Project website: https://microsoft.github.io/SkillOpt/
- GitHub repository: https://github.com/microsoft/SkillOpt
Comparison of similar products
Compared to traditional manual optimization or existing methods, SkillOpt’s advantages lie in its systematic approach and reliability.
| Optimization Methods | specificities | Comparison with SkillOpt |
|---|---|---|
| Manually written/fine-tuned | Relying on personal experience and trial and error, the results tend to be inconsistent and unstable as soon as the prompts get longer, since they can easily contradict each other. | SkillOpt uses task-driven, automated iterations to deliver quantifiable and reproducible results, freeing developers from the “game of guesswork.” |
| One-Time LLM Generation | Have a powerful LLM generate technical documentation directly, but the output is unpredictable and the quality varies. | SkillOpt is a closed-loop optimization system that continuously improves based on feedback; its outputs are validated and deliver results far superior to those of one-time generation. |
| Other Automatic Optimization Methods | Models such as TextGrad, GEPA, and EvoSkill improve through loosely controlled self-revision. | In evaluations of 52 different models, benchmarks, and frameworks, SkillOpt outperformed all comparable products, achieving consistent and significant improvements. |
| Model fine-tuning | Modifying model weights is costly, technically challenging, and may affect the model's general-purpose capabilities. | SkillOpt does not modify model parameters; it only optimizes external skill documentation. It is extremely cost-effective, easy to deploy, and completely avoids the problem of knowledge loss. |
Skills trained using SkillOpt also have excellentMobility Skills that have been optimized for one model or framework often yield significant performance improvements when applied to another model or framework, without the need for retraining.
data statistics
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