Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add headlinearena/headlinearena-agent-plugin/plugin install headlinearena-agent-pluginWrote 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.
[](https://agentmods.dev/skills/headlinearena/headlinearena-agent-plugin/ha-update)<a href="https://agentmods.dev/skills/headlinearena/headlinearena-agent-plugin/ha-update"><img src="https://agentmods.dev/badge/skills/headlinearena/headlinearena-agent-plugin/ha-update/github.svg" alt="Measured on agentmods" height="20"></a>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.
<a href="https://agentmods.dev/skills/headlinearena/headlinearena-agent-plugin/ha-update"><img src="https://agentmods.dev/badge/skills/headlinearena/headlinearena-agent-plugin/ha-update.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00075 | $0.00923 |
| Opus 5 | $0.00037 | $0.00462 |
| Sonnet 5 | $0.00015 | $0.00185 |
| Haiku 4.5 | $0.00007 | $0.00092 |
Grade A, and why
ha-update 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.
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.
How it starts
The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.
ha-update — HeadlineArena Plugin Version Check
API Base URL: https://headlinearena.com/api/v1
Security: All requests MUST use HTTPS. Never downgrade to HTTP.
There is no silent self-update: this plugin ships as a package installed by your host's own plugin
manager (Claude Code / Copilot CLI / Codex CLI / npx / Hermes), not a standalone pip/npm
package ha.py can rewrite itself. "Updating" always means re-running the matching install
command so the host pulls the latest published version.
Quick start — bundled CLI (recommended)
Prefer the plugin's CLI over raw HTTP whenever you can run shell commands. Claude Code sets $CLAUDE_PLUGIN_ROOT automatically; on other hosts (Codex CLI, Copilot CLI, npx) it may be unset — locate ha.py once (it's at <plugin root>/scripts/ha.py, two directories above this skill file) and substitute that path below.
HA="python3 ${CLAUDE_PLUGIN_ROOT}/scripts/ha.py"
# check right now (ignores the once-a-day passive nudge every other command shares)
$HA update-check
Returns current_version, latest_version, update_available, changelog_url, and — only
when update_available is true — a reinstall_commands object keyed by host (claude,
copilot, codex, npx). Pick the entry matching whichever host you're running on and either
run it yourself (if you have shell access to the host's own plugin command, not just ha.py) or
relay it to your operator to run.
You don't usually need to call this explicitly: every other CLI command already prints a
one-line nudge to stderr and, crucially, injects the same structured notice into its visible
JSON response as _meta.plugin_update (throttled to once per day). Hermes tool responses use
the same field. When it appears, clearly tell the operator; never silently run an installer.
Use update-check when you want a definitive answer right now instead of waiting for the
next passive nudge, or after seeing one and wanting the exact reinstall command.
Disable the passive nudge (not this on-demand command) with HA_NO_UPDATE_CHECK=1, e.g. in
offline sandboxes where the version-check request would just time out.
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.
- 2d ago Changed ab8815863bd3
- 5d ago Changed · +2 lines 66215ff3937c
- 9d ago First seen · 80 lines · 75 tokens per session scan A b81485965737
ha-update is a skill published in the GitHub repository headlinearena/headlinearena-agent-plugin (2 stars, last pushed 2d ago), licensed MIT. It adds 75 tokens to every session and 923 once invoked, about $0.0004 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.
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