implement-spec

An implementation workflow that turns a written specification or plan into code.

In plain words
What is it for?
Use it to implement planned features or fixes, connect tests to requirements, update plan progress, and run project checks.
Why use it?
It keeps development tied to documented requirements and requires verification before finishing.

Command for Cursor

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 commands/rhyanvargas/agentic-development-starter-kit/implement-spec
Clone the repo
git clone --depth 1 https://github.com/rhyanvargas/agentic-development-starter-kit

Made for: Cursor.

Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 401 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 $0.00000 $0.00401
Opus 5 $0.00000 $0.00200
Sonnet 5 $0.00000 $0.00080
Haiku 4.5 $0.00000 $0.00040

Measured yesterday against content hash 4b4dff1fb869, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

implement-spec 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 yesterday.

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.

.cursor/commands/implement-spec.md · 24 lines

What it actually says

/implement-spec

Implement from a specification or plan.

Skill

Read and follow skills/spec-driven-workflow. Honor @.cursor/rules/testing and @.cursor/rules/project-cmds for tests and verify commands. When the engineering-methods pack is installed, follow test-driven-development (and systematic-debugging on failures) — see docs/engineering-methods.md.

Usage

/implement-spec path/to/spec-or-plan.md

Behavior

  1. Clear (Medium+): confirm exploration is persisted in the living spec/plan; start this session lean — see skill gated procedure. Handoff: read living spec + plan + latest progress before coding (references/session-handoff.md). If the living spec changed after the plan was written, resync (/plan-impl) before coding.
  2. Read the spec or plan; follow the plan step-by-step when present. For bugfix specs, honor the Unchanged (KEEP) fence.
  3. Implement with tests mapped to requirements (or justify non-behavioral exceptions).
  4. Update plan todo status as steps complete (Cursor Plan YAML todos and/or portable checklist — see references/cursor-adapter.md / artifact-homes.md).
  5. Fail-closed verify: run project-cmds / project verify; fix failures before claiming done. If verify is missing, refuse “done” and point to /quick-start — do not invent a silent pass.
  6. Session end (Medium+ incomplete): update the plan/spec Handoff / Progress section (done / files touched / next REQ or T# / git expectation) per session-handoff.md.
  7. Suggest /review when implementation is complete — do not treat this session’s self-check as the evaluate pass (references/review-evaluator.md).
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. yesterday First seen · 24 lines · 0 tokens per session scan A 4b4dff1fb869

Subscribe to this mod's changes

implement-spec is a command published in the GitHub repository rhyanvargas/agentic-development-starter-kit (2 stars, last pushed 8d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 401 tokens. 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 2026-08-31.