How do I install the Design Twice skill?

Run npx skillmds@latest add garyld1962/design-twice-3 in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Design Twice safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Design Twice?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Design Twice free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Design Twice?

garyld1962 (@garyld1962) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Design Twice by garyld1962 — Agent Skill

Name: Design Twice
Author: garyld1962

Design Twice

Compare at least three contrasting module or API interfaces before committing to architecture. Use for unresolved interface design in feature/refactor work; skip settled designs, small bug fixes, and implementation-only requests.

garyld1962 Updated Sep 17, 2026

File contents

Design twice

Despite the name, compare at least three designs before recommending one.

Workflow

Inspect callers, data contracts, constraints, existing patterns and closed decisions. State the one interface decision and the behavior all alternatives must preserve.
Produce three substantially different designs:
- minimal surface: one to three public operations hiding the complexity;
- flexibility: broader composition and extension points;
- common case: make the usual caller simple, documenting edge-case tradeoffs.
For each, give a signature or schema, a realistic caller example, hidden complexity, error behavior, tradeoffs and likely misuse. Compare simplicity, depth, generality, implementation cost and ease of correct use. Do not compare only names or styling.
Use independent agents only when delegation is authorized and exposed by the host. Send the same requirements with a different design constraint to each. Otherwise work through all three locally and identify that this was one agent's comparison.
Recommend a design or synthesis with reasons tied to actual callers. Honor a user's delegation of routine technical choices; ask only about a material unresolved choice. Record the selected interface, authority and rejected alternatives in the repo's established decision format when the task includes planning or persistence.

Example

For a cache boundary, compare get/set, a configurable cache policy object, and a single get-or-load operation using the same expiry and error requirements.

Closed decisions and open decisions

Do not reopen a selected transport, persistence model or public contract. Compare only the remaining design freedom; expose any requirement conflict before choosing.

Do not

Do not implement the winning design unless requested, claim local passes are independent reviewers, or invent tools, models or parallel execution support.

Copilot integration

This skill is the durable entrypoint for Copilot hosts that load agent skills. The matching prompt file is an optional VS Code shortcut. Read repository instructions before edits; use the tools actually exposed by the host, including connected GitHub access when available. A prompt or skill does not itself grant additional permissions.

---name: design-twice-3description: Compare at least three contrasting module or API interfaces before committing to architecture. Use for unresolved interface design in feature/refactor work; skip settled designs, small bug fixes, and implementation-only requests.---# Design twiceDespite the name, compare at least three designs before recommending one.## Workflow1. Inspect callers, data contracts, constraints, existing patterns and closed decisions. State the one interface decision and the behavior all alternatives must preserve.2. Produce three substantially different designs: - minimal surface: one to three public operations hiding the complexity; - flexibility: broader composition and extension points; - common case: make the usual caller simple, documenting edge-case tradeoffs.3. For each, give a signature or schema, a realistic caller example, hidden complexity, error behavior, tradeoffs and likely misuse. Compare simplicity, depth, generality, implementation cost and ease of correct use. Do not compare only names or styling.4. Use independent agents only when delegation is authorized and exposed by the host. Send the same requirements with a different design constraint to each. Otherwise work through all three locally and identify that this was one agent's comparison.5. Recommend a design or synthesis with reasons tied to actual callers. Honor a user's delegation of routine technical choices; ask only about a material unresolved choice. Record the selected interface, authority and rejected alternatives in the repo's established decision format when the task includes planning or persistence.## ExampleFor a cache boundary, compare get/set, a configurable cache policy object, and asingle get-or-load operation using the same expiry and error requirements.## Closed decisions and open decisionsDo not reopen a selected transport, persistence model or public contract. Compare onlythe remaining design freedom; expose any requirement conflict before choosing.## Do notDo not implement the winning design unless requested, claim local passes are independentreviewers, or invent tools, models or parallel execution support.## Copilot integrationThis skill is the durable entrypoint for Copilot hosts that load agent skills.The matching prompt file is an optional VS Code shortcut. Read repository instructionsbefore edits; use the tools actually exposed by the host, including connected GitHubaccess when available. A prompt or skill does not itself grant additional permissions.

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