lookup-censys

lookup-censys is a skill for Claude Code, Codex from Liberty91LTD/cti-skills. It costs 57 tokens per session (1,955 once invoked), scanned A, original, MIT.

A retrieval tool for Censys, a service that indexes internet-connected hosts and their certificates. It looks up host details, TLS certificates, network ownership, locations, or search results.

In plain words
What is it for?
It helps investigate an IP address, find hosts sharing a TLS certificate, and run targeted Censys searches.
Why use it?
It provides deeper host and certificate information when another source such as Shodan does not provide enough detail, while helping avoid wasting limited query quota.

Skill for Claude CodeCodex

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

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is node tools/clis/censys.js ip <ip>.

Good fit It helps investigate an IP address, find hosts sharing a TLS certificate, and run targeted Censys searches.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/Liberty91LTD/cti-skills
agentmods
npx agentmods add skills/liberty91ltd/cti-skills/lookup-censys

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 lookup-censys

README.md
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Your own site
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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 lookup-censys

Your own site · 80×15
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Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,955 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 $0.00057 $0.01955
Opus 5 $0.00028 $0.00978
Sonnet 5 $0.00011 $0.00391
Haiku 4.5 $0.00006 $0.00196

Measured 12d ago against content hash 5717f16e2d6e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

lookup-censys 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 12d 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.

skills/lookup-censys/SKILL.md · 173 lines

How it starts

The opening of the file, as written. The whole thing — 173 lines — stays where its author put it; the contents beside it link to each section on GitHub.

lookup-censys

Queries Censys for host and certificate reconnaissance on IPs, or runs a Censys Search query. Retrieval only. Quota-aware — free tier is 250 queries/month.

When to invoke

  • Shodan wasn't sufficient and deeper host data is needed
  • TLS certificate pivoting (find other hosts sharing a cert)
  • Specific Censys Search query required

Do NOT invoke for:

  • Bulk enrichment (will exhaust quota)
  • IPs you can get from Shodan first

How to invoke

Two CLIs are provided. Pick by capability needed.

Auth note: Censys migrated to a single Personal Access Token (PAT) on the new Platform. The Node CLI uses the legacy Search API (HTTP Basic Auth with CENSYS_API_ID + CENSYS_API_SECRET); the Python CLI uses the new Platform API (Bearer auth with CENSYS_PAT). New accounts get a PAT — use the Python CLI. Old accounts may still have working legacy credentials and can use either.

Basic host + search — Node CLI (legacy Search API)

node tools/clis/censys.js ip <ip>
node tools/clis/censys.js search "<query>"      # Censys Search syntax

Requires CENSYS_API_ID + CENSYS_API_SECRET (legacy). Hits hosts/{ip} or hosts/search.

Full Platform surface — Python CLI (new Censys Platform SDK)

python3 tools/clis/censys.py host <ip> [--at-time ISO8601]
python3 tools/clis/censys.py timeline <ip> --start ISO8601 --end ISO8601
python3 tools/clis/censys.py services <ip>
python3 tools/clis/censys.py search "<query>" [--page-size N] [--page-token TOKEN] [--fields F1,F2]
python3 tools/clis/censys.py aggregate "<query>" --field FIELD [--buckets N] [--filter-by-query]
python3 tools/clis/censys.py certs view <cert_id>
python3 tools/clis/censys.py certs list <id1,id2,...>

Requires CENSYS_PAT (new). Self-bootstraps a private venv at tools/clis/.venv-censys/ on first run (installs censys-platform).

Capabilities the Node CLI doesn't have, ordered by CTI value:

  1. Aggregate — the unsung hero. Aggregations are free (do not consume query credits) and let you ask "how many hosts in this query break down by country / port / ASN / product?" in a single call. Use this BEFORE a search to scope the result set without spending credits.
  2. Host timeline — the activity history of a single IP between two timestamps. New in Platform.
  3. At-time host view — see what a host looked like at a past timestamp (Platform-only).
  4. Service listing — enumerate just the services on a host without the full record.
  5. Certificate view by ID + certificate list (bulk) — pull cert detail or batch fetch.
  6. Cursor-based pagination--page-token for traversing large result sets.

Read the full file on GitHub · 173 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. 12d ago First seen · 173 lines · 57 tokens per session scan A 5717f16e2d6e

Subscribe to this mod's changes

lookup-censys is a skill published in the GitHub repository Liberty91LTD/cti-skills (18 stars, last pushed 1mo ago), licensed MIT. It adds 57 tokens to every session and 1,955 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.