Competition Runtime Routing
Traces which host, proxy rule, or container serves a request in CTF sandbox challenges
- Repository
- zhaoxuya520/reverse-skill
- Stars
- 43,969
- Licence
- MIT
- Files
- 3 files
What it does
This is a downstream helper for a capture-the-flag (CTF) security sandbox workflow. Once a broader parent skill has set up the challenge context, the agent maps how a web request travels through reverse proxies, Host and forwarded headers, path-prefix rewrites and websocket upgrades to reach the right backend container. It then finds the smallest change to a request that alters routing, and records the evidence in a host-to-proxy-to-service-to-process map. Its instructions are written to reply in Simplified Chinese unless English is requested.
Great for
- Players working on web CTF challenges involving reverse proxies or virtual hosts
- Security students learning how Host headers and forwarded headers change routing
- Competition operators debugging which node serves a given route in a sandbox
Skip it if
- Production systems or real third-party domains, since the skill tells the agent to treat every hostname as a sandbox fixture unless evidence disproves it, which could mislead real investigations
- Request smuggling or parser-differential problems, which the file itself says should go to a different skill
- Use without the parent ctf-sandbox-orchestrator skill, because the file says it should only run after that skill is active
Try asking
- “Which container actually serves the /api route on this challenge host, and how do the X-Forwarded headers change that?”
- “Why does this public-looking domain still route to the sandbox instead of the real service?”
- “Trace how a websocket upgrade request resolves across the proxy and worker boundary.”
- “Re-run this request changing only the Host header and tell me which upstream it hits.”
Install in 3 steps
- 1
Download the skill
The ZIP contains the 3 original files, the MIT licence and an attribution note.
competition-runtime-routing.zip - 2
Add it to your agent
Claude Code (all projects)
mkdir -p ~/.claude/skills && unzip competition-runtime-routing.zip -d ~/.claude/skills/Claude Code / Agent SDK (this project only)
mkdir -p .claude/skills && unzip competition-runtime-routing.zip -d .claude/skills/Claude apps (web/desktop): Settings → Capabilities → Skills → Upload skill, and choose the ZIP.
- 3
Ask for the task
No special command needed — the agent reads the skill's description and loads it when your request matches. Try one of the prompts above.
Get better results
- Install the parent ctf-sandbox-orchestrator skill first, since this one is designed to be routed to from it.
- Provide the exact proxy snippets, headers and request examples so the agent can build an evidence chain rather than guessing.
- Only use it against sandboxes and challenges you are authorized to test.
What's inside
- agents/openai.yaml
- references/runtime-routing.md
- SKILL.md
Redistributed unmodified from zhaoxuya520/reverse-skill under the MIT licence. The assessment was drafted with AI from the skill's files on 2026-10-29. Skills can instruct your agent to run code — read SKILL.md and any scripts before installing.