AgentSkillTree
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Skill Authoring

Write a stable, testable agent skill with clear scope, contracts, actions, and validation.

Scope
Designing and documenting a single reusable skill. Not building the underlying tools it calls.
Last reviewed
Checked Jul 31, 2026

Executes these capabilities

Inside this skill

The internal capability tree shows how this skill gets its work done.

SSkill Authoring
  • scope definition
  • trigger design
  • input contract design
  • action sequencing
  • error handling
  • output contract design
  • skill testing
  • documentation

The contract

Input

  • The task the skill should handle
  • Examples of good and bad input
  • Available tools and permissions

Output

  • A SKILL.md with frontmatter and instructions
  • Test cases and validation methods

Deliverables

  • The skill file
  • A short test plan

Use cases

  • Reusing a workflow across projects
  • Sharing a team standard
  • Publishing a skill for others

Dependencies and replacements

Dependencies

  • A clear task definition
  • Access to the tools the skill calls

Required tools

  • A text editor
  • The agent environment to test in

Required permissions

  • Write access where the skill will run

Compatible with

  • validation-checklist
  • project-memory

Alternatives

  • A documented runbook instead of a skill
  • A prompt template

Replaceable components

  • The instruction format
  • The exact wording of steps

Reliability

Human checkpoints

  • Approve the scope before writing actions
  • Review test results before first release

Limitations

  • A skill cannot guarantee behavior across model versions
  • Underspecified environments break skills
  • Over-scoped skills are untestable

Failure modes

  • Scope creep from undocumented edge cases
  • Steps that assume unstated context
  • No tests, so regressions go unnoticed

Recovery steps

  • Narrow the scope and split the skill
  • Make inputs and expected outputs explicit
  • Add a test case for each failure mode

Validation methods

  • Run the skill twice on the same input and diff outputs
  • Test each failure mode and recovery path
  • Confirm a fresh agent can follow the instructions alone

Sources

Entry checked on Jul 31, 2026. Verification status reflects what AgentSkillTree has independently run, not the skill's own claims.

When to use

Use when you find yourself repeating the same multi-step procedure across projects or sessions. A skill captures the procedure once, with the boundaries and checks that make it repeatable.

How it works

Define the scope first, then the input and output contracts, then the ordered actions with failure branches, then the human checkpoints, then the tests. Documentation is the last step, written from the tested behavior, not from intent.