Library › Book 1 › The Skill Lifecycle
The Skill Lifecycle
3.1🔒OverviewA skill goes through six phases from installation to completion. Understanding this lifecycle is essential for debugging skill behavior…
3.2🔒Phase 1: InstallationSkills are installed from Git repositories, or -- the 2026-native path -- generated directly by the tool they wrap:
3.3🔒Phase 2: DiscoveryOn every conversation turn, the system scans all skill locations, reads each frontmatter, filters to skills with a description, and injects…
3.4🔒Phase 3: SelectionThere is no algorithmic routing. Selection happens inside the model's forward pass: it reads the skill descriptions and decides -- through…
3.5🔒Phase 4: InvocationWhen the agent decides to use a skill, it calls the Skill tool:
3.6🔒Phase 5: ExecutionWith the instructions in context, the agent executes: it reads the command surface from the SKILL.md and issues Bash commands…
3.7🔒Phase 6: Completion -- and Zero InfrastructureWhen the task finishes, the skill's effects unwind: elevated permissions and any model override revert to session defaults, while the…
3.8🔒Key Takeaways- Skills go through six phases: Install, Discover, Select, Invoke, Execute, Complete - Installation is npx skills add from a repo or…
3.9🔒Q&ASelf-Assessment Quiz1. How often does skill discovery happen? 2. What is the character budget for the skills listing? 3. Why is there no algorithmic routing…
3.10🔒Exercises[Beginner] Exercise 3.1: Run playwright-cli install --skills, find the generated SKILL.md, count the commands it documents, and compare its…
3.11🔒Career Translation- Applied the six-phase agent skill lifecycle (Install, Discover, Select, Invoke, Execute, Complete) to design, debug, and optimize…
3.12🔒Q&AInterview Depth CheckPrompt: Your browser automation skill never gets invoked. Debug it using the lifecycle. A strong answer covers: - Install: is the file at…