implement-spec

A command for carrying out an approved implementation plan or validated OpenSpec task list. It coordinates the work through a designated technical lead and delegated coding agents.

In plain words
What is it for?
Implementing approved plans or OpenSpec changes, optionally selecting a task group and applying branch, worktree, or other implementation constraints.
Why use it?
It prevents a bare issue from being treated as a complete execution plan when the project requires structured implementation instructions.

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/jabrena/plinth/implement-spec
Clone the repo
git clone --depth 1 https://github.com/jabrena/plinth

Made for: Cursor.

Per session 12 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,321 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 $0.00012 $0.02321
Opus 5 $0.00006 $0.01161
Sonnet 5 $0.00002 $0.00464
Haiku 4.5 $0.00001 $0.00232

Measured yesterday against content hash 7f128abf3a32, 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 · 142 lines

How it starts

The opening of the file, as written. The whole thing — 142 lines — stays where its author put it; the contents beside it link to each section on GitHub.

implement-spec

Deliver an approved implementation plan or validated OpenSpec task list through controlled implementation.

Usage

/implement-spec <approved-plan|openspec-change> [task-or-group] [constraints]

Accepted inputs

  • An approved implementation plan (*.plan.md)
  • An OpenSpec change containing a validated tasks.md
  • Optional task or group selection, branch/worktree context, and implementation constraints

A bare issue is context, not an execution contract. When repository policy requires structured planning and neither executable artifact exists, stop and direct the user to provide an approved implementation plan or run /create-spec.

Owner and delegation

  • Owner: @plinth-tech-lead
  • Delegation targets: @plinth-java-coder, @plinth-java-spring-boot-coder, @plinth-java-quarkus-coder, @plinth-java-micronaut-coder, or @plinth-no-java
  • The tech lead coordinates delivery and MUST NOT implement application code directly.

Mandatory execution contract

  • If the command runner is not @plinth-tech-lead, immediately delegate the whole command execution to @plinth-tech-lead and wait for its result.
  • @plinth-tech-lead MUST invoke the selected implementation agent for implementation, test, and verification work; naming an agent in the response is not delegation.
  • If agent invocation is unavailable in the current environment, stop and report that /implement-spec cannot proceed instead of implementing directly.
  • For OpenSpec inputs, pass the OpenSpec readiness gate below before skill discovery, Git-location changes, or implementation delegation.
  • Before any implementation agent starts, pass the branch/worktree gate below and report the selected isolation strategy.
  • Before any implementation agent starts, @plinth-tech-lead MUST publish a Skill discovery brief and pass an ordered candidate skills to read list in every implementation handoff.

OpenSpec readiness gate

  • After loading and structurally validating the selected change, determine the selected execution scope from the requested task or group, or all incomplete tasks when no narrower scope is supplied.
  • Require bidirectional traceability: every selected behavior-changing implementation task has one or more concrete scenarios in specs/**/spec.md, and every scenario applicable to the selected scope has an actionable implementation or verification task. Repository validation tasks must map to an explicit quality, safeguard, or verification obligation.
  • A concrete scenario defines its trigger, required preconditions, and observable outcome without unresolved placeholders. An actionable task names a specific remaining implementation or verification outcome; completed-only tasks do not provide executable work.
  • Treat evidence as not ready when it is absent, ambiguous, placeholder, completed-only, partial, or divergent from the selected change requirements or safeguards.
  • When the gate fails, stop and report each unsupported scenario or task, identify the owning OpenSpec artifact, and instruct the contributor to update the OpenSpec change and rerun /implement-spec.
  • The command must not invent acceptance criteria or tasks. A failed readiness gate stops before skill discovery, Git-location changes, or implementation delegation.
  • Do not require unrelated future task groups to be implementation-complete when a narrower task or group was explicitly selected.

Read the full file on GitHub · 142 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. yesterday First seen · 142 lines · 12 tokens per session scan A 7f128abf3a32

Subscribe to this mod's changes

implement-spec is a command published in the GitHub repository jabrena/plinth (435 stars, last pushed today), licensed Apache-2.0. It adds 12 tokens to every session and 2,321 once invoked, about $0.0001 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.