spec-driven-implementation

A spec-first workflow for substantial software features. It records what the feature should do in a product specification and, when needed, how it should be built in a technical specification.

In plain words
What is it for?
Use it to create and maintain PRODUCT.md and TECH.md files for significant features, usually alongside a corresponding Linear issue.
Why use it?
Writing the decisions down before coding reduces ambiguity and gives implementation and review a shared reference.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/warpdotdev/common-skills/spec-driven-implementation
Any agent
npx skills add warpdotdev/common-skills --skill spec-driven-implementation
Clone the repo
git clone --depth 1 https://github.com/warpdotdev/common-skills

Made for: Claude Code, Codex.

Per session 61 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,227 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00061 $0.01227
Opus 5 $0.00030 $0.00613
Sonnet 5 $0.00012 $0.00245
Haiku 4.5 $0.00006 $0.00123

Measured 2d ago against content hash 242028fe3ed0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

spec-driven-implementation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/spec-driven-implementation/SKILL.md · 144 lines

How it starts

The opening of the file, as written. The whole thing — 144 lines — stays where its author put it; the contents beside it link to each section on GitHub.

spec-driven-implementation

Drive a spec-first workflow for substantial features in Warp.

Overview

Use this skill for significant features where a written spec will improve implementation quality, reduce ambiguity, or make review easier. Be pragmatic: not every change needs specs.

Specs should usually live in:

  • specs/<linear-ticket-number>/PRODUCT.md
  • specs/<linear-ticket-number>/TECH.md

For example:

  • specs/APP-1234/PRODUCT.md
  • specs/APP-1234/TECH.md

specs/ should contain only ticket-named directories as direct children. Do not create engineer-named subdirectories or feature-slug directories there.

If a relevant Linear issue does not already exist, create one before writing specs. Use the Linear MCP tools directly:

  • list_teams to find the appropriate team
  • list_issue_labels to inspect the expected labels/tags
  • save_issue to create the issue with the appropriate team and labels

If the correct team or labels are not obvious from the request and surrounding context, use ask_user_question to clarify rather than guessing.

These specs should largely be written by agents, not by hand, and should be checked into source control so they can be reviewed and kept current with the code.

When specs are required

Strongly prefer specs when the change is substantial, such as:

  • product or architectural ambiguity
  • expected implementation size around 1k+ LOC
  • deep or cross-cutting stack changes
  • risky behavior changes where regressions would be expensive
  • work where agent quality will improve materially from clearer inputs

Specs are often unnecessary for:

  • small, local bug fixes
  • straightforward refactors
  • narrow UI tweaks with little ambiguity

For pure UI changes, the product spec is often useful while the tech spec may be unnecessary.

Workflow

1. Decide whether the feature needs specs

Evaluate the size, ambiguity, and risk of the feature. If specs will not meaningfully improve execution or review, skip them and focus on verification instead.

Read the full file on GitHub · 144 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 144 lines · 61 tokens per session scan A 242028fe3ed0

Subscribe to this mod's changes

spec-driven-implementation is a skill published in the GitHub repository warpdotdev/common-skills (413 stars, last pushed 2d ago), licensed MIT. It adds 61 tokens to every session and 1,227 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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