/skill-writer

name: skill-writer
description: Create, synthesize, and iteratively improve agent skills following the Agent Skills specification. Use when asked to "create a skill", "write a skill", "synthesize sources into a skill", "improve a skill from positive/negative examples", "update a skill", or "maintain skill docs and registration". Handles source capture, precision passes, authoring, registration, and validation.

Skill Writer

Use this as the single canonical workflow for skill creation and improvement. Primary success condition: maximize high-value input coverage before authoring while minimizing wasted runtime tokens.

Follow the workflow steps in order. Load only the reference files required for the step you are on. `SKILL.md` is the primary router: every bundled reference file should be flat under `references/` and listed here with a direct "open when..." reason.

Core Workflow References

| Open when you need to... | Read | |--------------------------|------| | choose the minimum workflow path for create, update, iterate, or research-first work | `references/mode-selection.md` | | choose the simplest adequate execution shape before deciding files | `references/execution-shapes.md` | | apply writing constraints for depth, concision, and portability | `references/design-principles.md` | | decide what belongs in `SKILL.md`, `references/`, `SPEC.md`, or supporting files | `references/reference-architecture.md` | | create or update the maintenance contract for a skill | `references/spec-template.md` | | find missing high-signal sources, including history and regressions | `references/source-discovery.md` | | adapt an upstream prompt, workflow, rubric, benchmark, or docs into a skill | `references/source-adaptation.md` | | run the full synthesis pass with coverage checks and source capture | `references/synthesis-path.md` | | author or update `SKILL.md`, `SPEC.md`, and supporting files | `references/authoring-path.md` | | improve trigger language and false-positive/false-negative behavior | `references/description-optimization.md` | | iterate from positive, negative, or fix examples | `references/iteration-path.md` | | store persistent working and holdout examples for future revisions | `references/iteration-evidence.md` | | choose a response template, schema, or output contract | `references/output-contracts.md` | | add or update evals for a skill's generated outputs or runtime behavior | `references/skill-evals.md` | | troubleshoot overloaded layouts, hidden refs, or other structure failures | `references/structure-troubleshooting.md` | | register the skill and run final validation checks | `references/registration-validation.md` |

Artifact Layout References

| Open when you need to... | Read | |--------------------------|------| | keep the whole skill inline in one coherent `SKILL.md` | `references/layout-inline-skill.md` | | split optional deep knowledge into focused routed references | `references/layout-reference-backed-skill.md` | | add scripts for deterministic automation or validation | `references/layout-script-backed-workflow.md` | | define a skill that is usually invoked with explicit arguments | `references/layout-argument-driven-skill.md` | | ship reusable templates, schemas, or other static assets | `references/layout-asset-template-skill.md` |

Workflow Mechanic References

| Open when you need to... | Read | |--------------------------|------| | break a task into fixed ordered steps | `references/workflow-prompt-chaining.md` | | classify requests and route them to different downstream paths | `references/workflow-routing.md` | | split independent work into parallel units or votes | `references/workflow-parallel.md` | | discover work units dynamically and coordinate worker outputs | `references/workflow-orchestrator-workers.md` | | run validate-fix-repeat checks during authoring or execution | `references/workflow-validation-loops.md` | | validate a plan before executing a risky action | `references/workflow-plan-validate-execute.md` |

Claude Code References

| Open when you need to... | Read | |--------------------------|------| | use Claude-specific frontmatter or invocation controls | `references/claude-frontmatter-invocation.md` | | use Claude argument fields or substitution variables | `references/claude-argument-substitutions.md` | | build a skill that runs in isolated `context: fork` | `references/claude-subagent-fork.md` | | build a skill that uses Claude hooks for deterministic enforcement | `references/claude-hook-backed.md` | | use Claude shell preprocessing for dynamic context injection | `references/claude-dynamic-context.md` |

Example Profiles

| Open when you need to... | Read | |--------------------------|------| | see the expected depth for a documentation-heavy skill | `references/example-documentation-skill.md` | | see the expected depth for a workflow-process skill | `references/example-workflow-process-skill.md` | | see what a good routed skill looks like | `references/example-router-skill.md` | | see what a good subagent-fork skill looks like | `references/example-subagent-fork-skill.md` | | see what a good hook-backed skill looks like | `references/example-hook-backed-skill.md` |

Step 1: Resolve target, path, and shape

1. Resolve the intended operation (`create`, `update`, `synthesize`, `iterate`) and inspect workspace prior art before choosing where files belong. 2. Choose the target skill root from observed conventions. If the canonical location is still unclear after inspection, ask one direct question before editing files. 3. Read `references/mode-selection.md` to choose the minimum required workflow paths. 4. Read `references/execution-shapes.md` to choose the primary execution shape. 5. Default to the simplest adequate shape. If selecting a more complex shape, record why simpler shapes were rejected. 6. Load only the exact artifact-layout, workflow-mechanic, and provider-specific leaf files required by that shape.