implementation-planner

implementation-planner is a skill for Claude Code, Codex from lfyxhappy/lfcode. It costs 59 tokens per session (291 once invoked), scanned A, original, MIT.

A method for making an implementation plan from a repository's current code, rules, tests, and project state before coding begins.

In plain words
What is it for?
It helps identify affected files and dependencies, define scope and risks, assign verifiable steps, and record validation or migration work.
Why use it?
It turns a broad feature, fix, migration, or refactor into ordered work without inventing details or overwriting existing plans.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It helps identify affected files and dependencies, define scope and risks, assign verifiable steps, and record validation or migration work.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/lfyxhappy/lfcode/implementation-planner
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.

Any agent
npx skills add lfyxhappy/lfcode --skill implementation-planner
Clone the repo
git clone --depth 1 https://github.com/lfyxhappy/lfcode

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for implementation-planner

README.md
[![agentmods](https://agentmods.dev/badge/skills/lfyxhappy/lfcode/implementation-planner/github.svg)](https://agentmods.dev/skills/lfyxhappy/lfcode/implementation-planner)
Your own site
<a href="https://agentmods.dev/skills/lfyxhappy/lfcode/implementation-planner"><img src="https://agentmods.dev/badge/skills/lfyxhappy/lfcode/implementation-planner/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for implementation-planner

Your own site · 80×15
<a href="https://agentmods.dev/skills/lfyxhappy/lfcode/implementation-planner"><img src="https://agentmods.dev/badge/skills/lfyxhappy/lfcode/implementation-planner.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 291 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00059 $0.00291
Opus 5.5 $0.00024 $0.00116
Sonnet 5.5 $0.00012 $0.00058
Haiku 4.5 $0.00006 $0.00029

Measured 1mo ago against content hash df2ffa2166cd, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

implementation-planner 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 1mo 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.

packages/lfcode/src/skill/lfcode/.bundle/implementation-planner/SKILL.md · 27 lines

What it actually says

Implementation Planner

Produce an execution plan that follows the existing repository rather than a generic checklist.

Workflow

  1. Read applicable repository instructions, current plan documents, branch status, and relevant diffs before defining work.
  2. Trace the affected behavior through source, contracts, storage, tests, packaging, and runtime entrypoints.
  3. Define the target state, scope exclusions, dependencies, risks, and decisions that must precede implementation.
  4. Break the work into ordered, independently verifiable steps. Name expected files or modules, validation commands, and release or migration actions where known.
  5. Keep the plan status synchronized with actual execution and record remaining gaps rather than marking work complete early.

Boundaries

  • Treat a request for a plan as read-only unless implementation is also explicitly requested.
  • Do not prescribe generated files, destructive migrations, releases, or external actions without confirming their repository-specific path and authorization.
  • Preserve existing user changes and existing plans; update only the plan that owns the requested work.

Completion Check

Report the plan location, target state, sequence, verification strategy, dependencies, and unresolved choices.

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. 1mo ago First seen · 27 lines · 59 tokens per session scan A df2ffa2166cd

Subscribe to this mod's changes

implementation-planner is a skill published in the GitHub repository lfyxhappy/lfcode (2 stars, last pushed 26d ago), licensed MIT. It adds 59 tokens to every session and 291 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-05.