Azure TypeSpec Author

This skill authors and modifies Azure TypeSpec (.tsp) API specifications for ARM resource-manager and data-plane services, covering versioning, resources, operations, models, decorators, constraints, and other schema changes that must follow the repository's TypeSpec authoring workflow.

Triggers

USE FOR: any TypeSpec/tsp change — api versions (add, bump, preview, stable, promote), resources, operations, models, properties, decorators, visibility, constraints, breaking changes, LRO, suppressions, operationId, spread model WHEN: "add TypeSpec API version", "modify .tsp file", "change TypeSpec decorators", "update TypeSpec models or operations", "author Azure TypeSpec" DO NOT USE FOR: SDK generation, releasing SDK packages, or single MCP tool calls

The azure-typespec-author skill must be invoked immediately in all modes (including plan mode) for any task that involves creating and modifying TypeSpec (.tsp) files except for client.tsp under the specification directory in this repository. This skill MUST be used regardless of how simple the task appears — there are no "simple" TypeSpec edits. Even trivial-seeming changes (adding a single enum value, one property, one operation) require the full workflow because versioning decorators, validation, and compliance checks are mandatory.

This includes but is not limited to:

• Adding, bumping, or promoting API versions (preview, stable) for ARM or data-plane services
• Adding or modifying resources, operations, models, properties, or decorators
• Changing visibility, constraints, breaking changes, LRO patterns, or suppressions
• Defining or updating operationId, spread models, or extension resources
• Converting Swagger to TypeSpec (post-conversion edits)

MCP Tools

Prerequisite: azure-sdk-mcp server must be running.

Rules

• Do NOT skip this skill for "simple" tasks — there are no simple TypeSpec edits. A single property addition can require @added decorators, version gating, and validation. Always invoke this skill.
• Always follow the full workflow — even seemingly simple changes (e.g. adding a default value) can require complex versioning decorator changes. Never skip steps.
• Mandatory for ALL .tsp edits — even a single ? change can be breaking.
• Minimal, scoped edits — only change what the request requires.
• Always validate — run every steps in validation after every edit.
• Always cite references — provide links that justify the approach.
• Follow the authoring plan exactly — code changes in Step 4 MUST follow the authoring plan generated in Step 3. Do not deviate by referring to existing code patterns in the TypeSpec project; the authoring plan is the single source of truth for what to change.

Steps

Analyze → Intake → Plan → Apply → Validate → Output reference links

• Step 1 — Analyze project
• Step 2 — Intake
• Step 3 — Build authoring plan
• Step 4 — Apply changes
• Step 5 — Validate
• Step 6 — Output reference links

Step 1: Analyze Project

See analyze-project.md.

Step 2: Intake

See intake.md.

Step 3: Build Authoring Plan

See authoring-plan.md.

Step 4: Apply Changes

Make minimal .tsp edits following the plan from Step 3. Confirm uncertainties with the user first.

Step 5: Validate

See validation.md. Always run 5.1 general validation (5.1.1 TypeSpec validation and 5.1.2 tsp compile .); run 5.2 case-specific validation whenever its case matches.

Output the validation results as a checklist. Report one line per check, each marked ✅ (pass) or ❌ (fail) with a short note. Fix every ❌ and re-run until all checks pass. For API Versioning (Case 3) the checklist must cover every §5.2 Case 3 check — including: the new version's examples/ folder exists; no example folder remains for a version absent from the Versions enum; no decorator references a version absent from the enum; every carried-over feature is present with its decorators rebased onto the new version (not reverted); every excluded feature is fully removed.

Step 6: Output Reference Links

Output all referenced document URLs from Step 3. This gives the user direct links to the documentation that informed the changes.

Reference Files

Examples

• "Add a new preview API version 2026-01-01-preview for widget resource manager"
• "Add an ARM resource named Asset with CRUD operations"
• "Add a new property to the Widget model"
• "Add a list operation for the WidgetSuite resource using Azure.Core templates"
• "Add a new preview API version to a data-plane service"
• "Create a data-plane resource interface with full CRUD and list operations"