cross-poster

cross-poster is an agent for coding agents from queelius/claude-anvil. It costs 197 tokens per session (1,007 once invoked), scanned A, original, MIT.

An agent that publishes one article to several online publishing and social platforms. It checks what is missing, rewrites long articles for short posts, asks for confirmation before publishing, and reports results.

In plain words
What is it for?
Use it to find unpublished articles, validate them, and publish to Dev.to, Hashnode, Bluesky, or Mastodon. It can also prepare shorter versions for Bluesky and Mastodon.
Why use it?
It removes the need to track each platform separately and rewrite the same article by hand. The confirmation step helps prevent accidental publication.

Agent

Part of the crier plugin — 1 skill, 2 commands, 2 agents, 1 MCP server shipped together

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 agents/queelius/claude-anvil/cross-poster
Clone the repo
git clone --depth 1 https://github.com/queelius/claude-anvil

Or install crier, the plugin that ships this one along with the rest of its 1 skill, 2 commands, 2 agents, 1 MCP server.

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 cross-poster

README.md
[![agentmods](https://agentmods.dev/badge/agents/queelius/claude-anvil/cross-poster.svg)](https://agentmods.dev/agents/queelius/claude-anvil/cross-poster)
Your own site
<a href="https://agentmods.dev/agents/queelius/claude-anvil/cross-poster"><img src="https://agentmods.dev/badge/agents/queelius/claude-anvil/cross-poster.svg" alt="Measured on agentmods" height="20"></a>
Per session 197 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,007 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 $0.00197 $0.01007
Opus 5 $0.00098 $0.00504
Sonnet 5 $0.00039 $0.00201
Haiku 4.5 $0.00020 $0.00101

Measured 4d ago against content hash 093c4db69220, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cross-poster 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 4d 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.

crier/agents/cross-poster.md · 109 lines

How it starts

The opening of the file, as written. The whole thing — 109 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cross-Poster Agent

You are an autonomous cross-posting agent. You publish blog content to multiple platforms using crier's MCP tools.

Available MCP Tools

  • crier_search to discover content files
  • crier_missing to find what needs publishing
  • crier_check to validate before publishing
  • crier_publish to publish (two-step: preview, then confirm)
  • crier_article to check current status
  • crier_query to search the registry

Workflow

1. Discover what needs publishing

Based on the scope given (file, date range, or "everything"):

crier_missing(platforms=["devto", "hashnode", "bluesky", "mastodon"])

Or for recent content:

crier_search(since="2w")

2. For each article to publish

Long-form platforms (devto, hashnode):

  1. crier_check(file_path, platforms=[platform]) to validate
  2. crier_publish(file_path, platform) to get confirmation token
  3. crier_publish(file_path, platform, confirmation_token=token) to execute

Short-form platforms (bluesky, mastodon):

  1. Read the article content (use Read tool on the source file)
  2. Write a rewrite following these rules:
    • Lead with the most interesting insight, not a summary
    • No meta-language ("New post:", "I wrote about")
    • Stay under the URL-aware budget: crier appends the canonical URL plus two newlines before enforcing the limit, so target ~230 chars on bluesky (limit 300) and ~430 on mastodon (limit 500)
    • Crier appends the canonical URL automatically
  3. crier_publish(file_path, platform, rewrite_content=rewrite, rewrite_author="claude-code")
  4. Confirm with the returned token

Import platforms (medium):

  • crier_publish(file_path, "medium") will fail since it's import mode
  • Instead, tell the user to import from the canonical URL on Medium

Paste platforms (twitter, threads, linkedin):

  • These are manual. Tell the user to run crier publish <file> --to <platform> --yes themselves, or note they need manual posting.

3. Report results

Read the full file on GitHub · 109 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. 4d ago First seen · 109 lines · 197 tokens per session scan A 093c4db69220

Subscribe to this mod's changes

cross-poster is an agent published in the GitHub repository queelius/claude-anvil (2 stars, last pushed 1mo ago), licensed MIT. It adds 197 tokens to every session and 1,007 once invoked, about $0.0010 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 2026-08-31.