ultra-plan

ultra-plan is a skill for Claude Code from davistroy/claude-marketplace. It costs 52 tokens per session (4,361 once invoked), scanned A, original, MIT.

A structured planning process for investigating and designing solutions to bug lists, feature requests, or related code changes before implementation.

In plain words
What is it for?
Use it to analyze issues, map interactions, design an implementation approach, and check whether an existing plan still matches the code.
Why use it?
It helps uncover how changes affect the rest of a codebase and produces a coordinated plan for related work.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions CLAUDE.md; mentions subagents.

Part of the personal-plugin plugin — 29 skills, 23 commands, 10 agents, 2 hooks shipped together

Good fit Use it to analyze issues, map interactions, design an implementation approach, and check whether an existing plan still matches the code.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/davistroy/claude-marketplace/ultra-plan
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 davistroy/claude-marketplace --skill ultra-plan
Clone the repo
git clone --depth 1 https://github.com/davistroy/claude-marketplace

Made for: Claude Code.

Or install personal-plugin, the plugin that ships this one along with the rest of its 29 skills, 23 commands, 10 agents, 2 hooks.

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 ultra-plan

README.md
[![agentmods](https://agentmods.dev/badge/skills/davistroy/claude-marketplace/ultra-plan/github.svg)](https://agentmods.dev/skills/davistroy/claude-marketplace/ultra-plan)
Your own site
<a href="https://agentmods.dev/skills/davistroy/claude-marketplace/ultra-plan"><img src="https://agentmods.dev/badge/skills/davistroy/claude-marketplace/ultra-plan/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 ultra-plan

Your own site · 80×15
<a href="https://agentmods.dev/skills/davistroy/claude-marketplace/ultra-plan"><img src="https://agentmods.dev/badge/skills/davistroy/claude-marketplace/ultra-plan.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,361 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 $0.00052 $0.04361
Opus 5 $0.00026 $0.02181
Sonnet 5 $0.00010 $0.00872
Haiku 4.5 $0.00005 $0.00436

Measured 8d ago against content hash 8d1d89d3f003, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

ultra-plan 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 8d 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.

plugins/personal-plugin/skills/ultra-plan/SKILL.md · 385 lines

How it starts

The opening of the file, as written. The whole thing — 385 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Ultra Plan

Build a detailed, architecturally sound implementation plan for the provided issues, changes, updates, or features. This is a rigid workflow -- follow every phase in order. Do not skip phases or combine them. Each phase produces a distinct deliverable that gates the next.

See also: /create-plan for requirements-driven planning. /plan-improvements for codebase analysis and improvement recommendations.

Inputs

The user provides one or more of:

  • A bug list, feature request list, or change set
  • A GitHub issue or PR with identified problems
  • A review document or audit with findings
  • Verbal description of needed changes

If the input is ambiguous or incomplete, ask clarifying questions before starting Phase 0.

Arguments

Argument Description
(none) Default mode: run the full rigid workflow (Phases 0-5)
--refresh Drift detection mode: compare existing plan against current code state (see below)

Drift Detection Mode (--refresh)

When invoked with --refresh, ultra-plan skips the normal Phase 0-5 workflow and instead checks whether an existing plan still matches the codebase.

Prerequisites:

  • IMPLEMENTATION_PLAN.md (or --input <path>) must exist
  • If no plan file exists, report: "No implementation plan found. Run /ultra-plan to create one, or specify a path with --refresh --input <path>."

Workflow:

Step 1: Read the Plan

Read the plan file. Extract all work items with their:

  • Files Affected (expected file paths)
  • Acceptance Criteria (expected behaviors)
  • Status (PENDING, IN_PROGRESS, COMPLETE)

Step 2: Check Each Item Against Code

For each work item (focus on COMPLETE items — they're most likely to drift):

  1. File existence: Do the listed files still exist? Were any renamed or deleted?
  2. Acceptance criteria: For COMPLETE items, do the acceptance criteria still hold? (Read the relevant code and check.)
  3. New code: Has code been added in the affected areas that the plan doesn't account for?

Read the full file on GitHub · 385 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. 8d ago First seen · 385 lines · 52 tokens per session scan A 8d1d89d3f003

Subscribe to this mod's changes

ultra-plan is a skill published in the GitHub repository davistroy/claude-marketplace (5 stars, last pushed 4d ago), licensed MIT. It adds 52 tokens to every session and 4,361 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 2026-09-04.

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