github-url-intercept

name	github-url-intercept
version	2.1.0
description	BLOCKING INTERCEPT: When ANY github.com URL appears in user input, STOP and use this skill. Never fetch GitHub HTML pages directly - they are 5-10MB and will exhaust your context window. This skill routes URLs to efficient API calls (1-50KB). Triggers on: pull/, issues/, blob/, tree/, commit/, compare/, discussions/. Use when you paste a GitHub URL, say "analyze this PR", "look at this issue", or "what does this commit do". Do NOT use for creating PRs, posting comments, or adding labels (use github instead).
license	MIT
metadata	{"domains":["github","url-parsing","context-optimization"],"type":"interceptor","complexity":"low","priority":"critical","related_skills":["github"]}

GitHub URL Intercept

CRITICAL: This skill activates AUTOMATICALLY when you see ANY github.com URL. Do NOT use web_fetch, curl, or any browser-based fetch on GitHub URLs. Doing so wastes 1-2.5 MILLION tokens on HTML that provides no useful data.

MANDATORY BEHAVIOR: Parse the URL → Route to API → Return structured JSON.

---

Quick Reference (Copy-Paste Commands)

When you see a GitHub URL, use these commands immediately:

SCRIPTS_DIR="${CLAUDE_PLUGIN_ROOT:-.claude}/skills/github/scripts"

# PR URL → Use this
python3 "$SCRIPTS_DIR/pr/get_pr_context.py" --pull-request {n} --owner {owner} --repo {repo}

# Issue URL → Use this
python3 "$SCRIPTS_DIR/issue/get_issue_context.py" --issue {n} --owner {owner} --repo {repo}

# File/blob URL → Use this
gh api repos/{owner}/{repo}/contents/{path}?ref={ref}

# Commit URL → Use this
gh api repos/{owner}/{repo}/commits/{sha}

# Comment fragment (#discussion_r{id}) → Use this
gh api repos/{owner}/{repo}/pulls/comments/{id}

---

Triggers

Phrase	Action
Any github.com URL in user input (even bare URL pasted alone)	Parse URL type and route to API
analyze / research / scan + GitHub URL	Route based on URL type
URL + question (e.g., "...#r123 what's the tracking issue?")	Extract fragment, call specific API
Multiple GitHub URLs in one prompt	Process each URL, batch API calls

---

When to Use

Use this skill when:

• Any github.com URL appears in user input (automatic activation)
• User pastes a PR, issue, commit, file, or actions URL
• User asks to "analyze" or "review" a GitHub link

Use github instead when:

• Performing mutations (creating PRs, posting comments, adding labels)
• Operating on the current repository without a URL

URL Patterns (Detailed Reference)

Pattern	Example	Why Intercept
github.com/.../pull/	https://github.com/owner/repo/pull/123	PR HTML is 5-10MB
github.com/.../pull/.../checks	https://github.com/owner/repo/pull/123/checks?check_run_id=...	CI checks page bloat
github.com/.../pull/.../files or /changes	https://github.com/owner/repo/pull/123/files#r123456	Diff view with comment fragment
github.com/.../issues/	https://github.com/owner/repo/issues/456	Issue HTML is 2-5MB
github.com/.../actions/runs/	https://github.com/owner/repo/actions/runs/123/job/456	Workflow run page bloat
github.com/.../blob/	https://github.com/owner/repo/blob/main/file.py	File page has nav bloat
github.com/.../tree/	https://github.com/owner/repo/tree/main/src	Directory listing bloat
github.com/.../commit/	https://github.com/owner/repo/commit/abc123	Commit page overhead
github.com/.../compare/	https://github.com/owner/repo/compare/main...feat	Diff page overhead
github.com/.../discussions/	https://github.com/owner/repo/discussions/789	Discussion page bloat
Fragment #discussion_r{id}	Review comment ID in /changes or /files URL	Extract ID, call API directly
Fragment #issuecomment-{id}	Issue comment ID	Extract ID, call API directly
Fragment #pullrequestreview-{id}	Review ID	Extract ID, call API directly
Fragment (short form)

---

Decision Flow

GitHub URL detected in user input
│
├─ Has fragment (#pullrequestreview-, #discussion_r, #issuecomment-)?
│     Yes → Extract ID, use gh api for specific comment/review
│
├─ Is /pull/{n}?
│     Yes → get_pr_context.py --pull-request {n} --owner {o} --repo {r}
│           (or get_pr_review_comments.py / get_pr_review_threads.py for comments)
│
├─ Is /issues/{n}?
│     Yes → get_issue_context.py --issue {n} --owner {o} --repo {r}
│
├─ Is /blob/{ref}/{path} or /tree/{ref}/{path}?
│     Yes → gh api repos/{o}/{r}/contents/{path}?ref={ref}
│
├─ Is /commit/{sha}?
│     Yes → gh api repos/{o}/{r}/commits/{sha}
│
└─ Is /compare/{base}...{head}?
      Yes → gh api repos/{o}/{r}/compare/{base}...{head}

---

Process

Phase 1: URL Detection and Parsing

Step	Action	Verification
1.1	Detect github.com URL in user input	URL pattern matched
1.2	Extract owner/repo from path	Both values non-empty
1.3	Identify URL type (pull, issues, blob, tree, commit, compare)	Type classified
1.4	Extract fragment ID if present	Fragment parsed or null

Phase 2: Route Selection

Step	Action	Verification
2.1	Check if github skill script exists for URL type	Script path resolved
2.2	If script exists → use github skill (primary route)	Script invocation planned
2.3	If no script → use gh api (fallback route)	API command constructed
2.4	For fragments → always use gh api with specific endpoint	Endpoint includes ID

Phase 3: Execution

Step	Action	Verification
3.1	Execute selected command	Command runs without error
3.2	Receive structured JSON response	Success: true for scripts
3.3	Parse relevant fields for user query	Response processed

---

URL Routing Table

Primary: Use GitHub Skill Scripts

URL Pattern	Script	Parameters
/pull/{n}	get_pr_context.py	--pull-request {n} --owner {o} --repo {r}
/pull/{n} (with diff)	get_pr_context.py	--pull-request {n} --include-diff
/pull/{n} (review comments)	get_pr_review_comments.py	--pull-request {n}
/pull/{n} (review threads)	get_pr_review_threads.py	--pull-request {n}
/pull/{n} (CI status)	get_pr_checks.py	--pull-request {n}
/issues/{n}	get_issue_context.py	--issue {n} --owner {o} --repo {r}

Script location: .claude/skills/github/scripts/

Fallback: Raw gh Commands

Use only when no script exists for the operation:

URL Pattern	API Call
/pull/{n}#pullrequestreview-{id}	gh api repos/{o}/{r}/pulls/{n}/reviews/{id}
/pull/{n}#discussion_r{id}	gh api repos/{o}/{r}/pulls/comments/{id}
/pull/{n}/files#r{id} or /changes#r{id}	gh api repos/{o}/{r}/pulls/comments/{id}
/pull/{n}#issuecomment-{id}	gh api repos/{o}/{r}/issues/comments/{id}
/pull/{n}/checks	gh api repos/{o}/{r}/check-runs?head_sha=... or use get_pr_checks.py
/issues/{n}#issuecomment-{id}	gh api repos/{o}/{r}/issues/comments/{id}
/actions/runs/{run_id}	gh api repos/{o}/{r}/actions/runs/{run_id}
/actions/runs/{run_id}/job/{job_id}	gh api repos/{o}/{r}/actions/jobs/{job_id}
/blob/{ref}/{path}	gh api repos/{o}/{r}/contents/{path}?ref={ref}
/tree/{ref}/{path}	gh api repos/{o}/{r}/contents/{path}?ref={ref}
/commit/{sha}	gh api repos/{o}/{r}/commits/{sha}
/compare/{base}...{head}	gh api repos/{o}/{r}/compare/{base}...{head}

---

URL Parsing Pattern

Extract owner, repo, and resource from GitHub URLs:

https://github.com/{owner}/{repo}/pull/{number}
https://github.com/{owner}/{repo}/issues/{number}
https://github.com/{owner}/{repo}/blob/{ref}/{path}
https://github.com/{owner}/{repo}/tree/{ref}/{path}
https://github.com/{owner}/{repo}/commit/{sha}
https://github.com/{owner}/{repo}/compare/{base}...{head}

Fragment extraction (when present):

• #pullrequestreview-{id} → Review ID
• #discussion_r{id} → Discussion comment ID
• #issuecomment-{id} → Issue comment ID

---

Why This Matters (CRITICAL)

Fetching GitHub HTML is catastrophic for your context window:

Method	Response Size	Token Cost	Time	Usability
❌ HTML fetch	5-10 MB	1-2.5M tokens	10-30s	UNUSABLE - HTML noise, no structured data
✅ API call	1-50 KB	250-12K tokens	0.5-2s	Clean JSON with exactly what you need
✅ Script	1-50 KB	250-12K tokens	0.5-2s	Structured output, error handling

Impact: 100-1000x reduction in token consumption.

If you fetch GitHub HTML directly, you will:

1. Consume your entire context window on ONE page
2. Get no useful structured data (just HTML soup)
3. Be unable to process subsequent user requests
4. Need to start a new conversation

ALWAYS use this skill when you see a GitHub URL.

---

Examples

Bare URL Pasted (Most Common!)

Input: "https://github.com/rjmurillo/ai-agents/pull/735/checks?check_run_id=59355308734"

Action:
  1. Parse: owner=rjmurillo, repo=ai-agents, pr=735, type=checks
  2. Route: python3 "$SCRIPTS_DIR/pr/get_pr_checks.py" --pull-request 735 --owner rjmurillo --repo ai-agents

URL with Question After It

Input: "https://github.com/owner/repo/pull/715/changes#r2656144507 are the graph refactoring items part of Issue 722?"

Action:
  1. Extract fragment: r2656144507 (review comment ID)
  2. Call: gh api "repos/owner/repo/pulls/comments/2656144507"
  3. Answer user's question using the comment content

Multiple URLs in One Prompt

Input: "https://github.com/owner/repo/pull/715#discussion_r123 https://github.com/owner/repo/pull/715#discussion_r456"

Action:
  1. Parse each URL
  2. Batch: gh api "repos/owner/repo/pulls/comments/123"
  3. Batch: gh api "repos/owner/repo/pulls/comments/456"

Research/Analyze Pattern

Input: "analyze https://github.com/modu-ai/moai-adk for insights"

Action:
  1. Use deepwiki MCP or gh api to get repo info
  2. Call: gh api "repos/modu-ai/moai-adk" (NOT web_fetch!)

CI/Actions Run URL

Input: "https://github.com/owner/repo/actions/runs/20675405338/job/59362398542?pr=740"

Action:
  1. Extract: run_id=20675405338, job_id=59362398542
  2. Call: gh api "repos/owner/repo/actions/jobs/59362398542"

PR URL → Script

Input: "Review this: https://github.com/owner/repo/pull/123"

Action:
  python3 "$SCRIPTS_DIR/pr/get_pr_context.py" --pull-request 123 --owner owner --repo repo

File URL → API

Input: "would a hook like https://github.com/ruvnet/claude-flow/blob/main/.claude/settings.json help?"

Action:
  gh api "repos/ruvnet/claude-flow/contents/.claude/settings.json?ref=main"

---

Anti-Patterns (NEVER DO THESE)

❌ NEVER	Why It's Catastrophic	✅ Do This Instead
web_fetch("https://github.com/...")	5-10 MB HTML, 1-2.5M tokens WASTED	Parse URL, use script or gh api
curl https://github.com/...	Same catastrophic result	Use gh CLI for authentication + JSON
fetch / requests.get on GitHub URLs	Same catastrophic result	Route through this skill
gh pr view without --json	Unstructured text output	Use get_pr_context.py for structured JSON
Fetching full page to find one comment	Fetches 5MB to read 500 bytes	Extract fragment ID (#discussion_r...), call specific endpoint
Ignoring GitHub URLs in user input	User expects you to understand the link	ALWAYS parse and route
Hardcoding owner/repo in commands	Breaks when user shares fork/different repo	Extract from URL path

RED FLAG PHRASES - If you're about to do any of these, STOP:

• "Let me fetch that page..."
• "I'll retrieve the content from that URL..."
• "Accessing the GitHub page..."

These indicate you're about to waste millions of tokens. Use this skill instead.

---

Scripts

test_url_routing.py

Routes GitHub URLs to appropriate API access methods with CWE-78 command injection protection.

python3 .claude/skills/github-url-intercept/scripts/test_url_routing.py <github-url>

---

Related Skills

Skill	When to Use
github	Full PR/issue operations (mutations, reactions, labels)
pr-comment-responder	Systematic PR review response

---

Verification

After routing a GitHub URL, run the bundled validator and require exit 0:

python3 .claude/skills/github-url-intercept/scripts/test_url_routing.py --url "$GITHUB_URL"
echo "exit=$?"   # must be 0; exit 1 means invalid URL or no routing available

• test_url_routing.py exited 0 (non-zero = invalid URL or unroutable type; routing is not valid)
• Extracted owner/repo from URL path
• Identified URL type (PR, issue, blob, commit, compare)
• Extracted fragment ID if present (#discussion_r, #issuecomment-, #pullrequestreview-)
• Selected appropriate github skill script (primary) or gh command (fallback)
• Did NOT use web_fetch, curl, or browser-based fetch on the URL
• Received structured JSON response with Success: true (for scripts)