github-planner

A tool for turning a GitHub issue—a tracked task or bug—into a detailed coding plan after examining the relevant parts of the repository.

In plain words
What is it for?
It fetches issue details, identifies affected files and architecture, and outlines implementation steps, risks, and the expected changes.
Why use it?
It helps clarify the issue's requirements, boundaries, and acceptance criteria before code changes begin.

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/syi0808/screenize/github-planner
Any agent
npx skills add syi0808/screenize --skill github-planner
Clone the repo
git clone --depth 1 https://github.com/syi0808/screenize

Made for: Claude Code, Codex.

Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 712 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 $0.00056 $0.00712
Opus 5 $0.00028 $0.00356
Sonnet 5 $0.00011 $0.00142
Haiku 4.5 $0.00006 $0.00071

Measured 2d ago against content hash c6a9ae9d88bf, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

github-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 2d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/create_plan.py, scripts/fetch_issue.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.claude/skills/github-planner/SKILL.md · 98 lines

How it starts

The opening of the file, as written. The whole thing — 98 lines — stays where its author put it; the contents beside it link to each section on GitHub.

GITHUB ISSUE IMPLEMENTATION PLANNER

Fetch a GitHub issue, analyze its requirements, explore the relevant codebase, and produce a comprehensive implementation plan.

When to use: Execute /plan-issue with a GitHub issue URL or number to generate an implementation plan before starting work.

Step 1: Fetch Issue

Run the fetch script to retrieve issue details:

uv run .claude/skills/github-planner/scripts/fetch_issue.py <issue_url_or_number>

Accepts:

  • Full URL: https://github.com/owner/repo/issues/123
  • Short URL: owner/repo#123
  • Issue number (uses current repo): 123 or #123

The script outputs structured JSON with title, body, labels, comments, and metadata.

Step 2: Analyze Issue

Parse the fetched issue content and identify:

  1. Problem statement - What needs to be solved
  2. Proposed solution - If described in the issue
  3. Acceptance criteria - Explicit or inferred requirements
  4. Scope boundaries - What is and isn't included

Step 3: Explore Codebase

Based on the analysis, explore relevant parts of the codebase:

  1. Use Glob/Grep to find files related to the issue's domain
  2. Read key files to understand current architecture
  3. Identify integration points and dependencies
  4. Check for existing patterns that the implementation should follow
  5. Reference CLAUDE.md for project architecture and conventions

Step 4: Generate Implementation Plan

Write the plan to private-docs/plans/<issue-number>-<slug>.md using the template:

uv run .claude/skills/github-planner/scripts/create_plan.py \
  --issue <number> \
  --title "<issue-title-slug>"

Fill the generated template with:

  • Overview: Issue summary and goals
  • Architecture Analysis: How changes fit into existing architecture
  • Implementation Steps: Ordered tasks with specific file changes
  • Files to Modify/Create: Exhaustive list with descriptions
  • Risk Assessment: Potential issues, edge cases, breaking changes
  • Testing Strategy: How to verify the implementation

Read the full file on GitHub · 98 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 98 lines · 56 tokens per session scan A c6a9ae9d88bf

Subscribe to this mod's changes

github-planner is a skill published in the GitHub repository syi0808/screenize (602 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 56 tokens to every session and 712 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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