context-guard

context-guard is a plugin for Claude Code from melodic-software/claude-code-plugins. Its token cost is not measured, scanned A, original, MIT.

A plugin that observes how much of each agent session's context window is being used and classifies that usage into smart, acceptable, or dumb zones. A context window is the amount of conversation and information the agent can consider at once.

In plain words
What is it for?
It is for recording per-session context usage, reporting worse zone changes, preserving evidence after compaction, and optionally blocking new changes when context is critically low.
Why use it?
It makes declining context capacity visible and can warn the operator when a session needs attention or a handoff.

Plugin for Claude Code

Written for Claude Code: a Claude Code plugin manifest.

Good fit It is for recording per-session context usage, reporting worse zone changes, preserving evidence after compaction, and optionally blocking new changes when context is critically low.

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Install in Claude Code
/plugin marketplace add melodic-software/claude-code-plugins
/plugin install context-guard
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.

Clone the repo
git clone --depth 1 https://github.com/melodic-software/claude-code-plugins

Made for: Claude Code.

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 context-guard

README.md
[![agentmods](https://agentmods.dev/badge/plugins/melodic-software/claude-code-plugins/context-guard/github.svg)](https://agentmods.dev/plugins/melodic-software/claude-code-plugins/context-guard)
Your own site
<a href="https://agentmods.dev/plugins/melodic-software/claude-code-plugins/context-guard"><img src="https://agentmods.dev/badge/plugins/melodic-software/claude-code-plugins/context-guard/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.

agentmods 80×15 button for context-guard

Your own site · 80×15
<a href="https://agentmods.dev/plugins/melodic-software/claude-code-plugins/context-guard"><img src="https://agentmods.dev/badge/plugins/melodic-software/claude-code-plugins/context-guard.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session not measured What this adds to a session before it is invoked.
When invoked not measured Not applicable: nothing here is loaded into a session.
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.
Security

Grade A, and why

context-guard 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.

plugins/context-guard/.claude-plugin/plugin.json · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

{
  "name": "context-guard",
  "version": "1.0.2",
  "description": "Per-session context-window observability. A mod writes each session's context-window figures to a snapshot file and shows the person a toast and a transcript line when the context zone (smart, acceptable or dumb, from bands in zones.json) worsens; with model_notices on (off by default) it also tells Claude the zone at each crossing, approach and compaction. /context-guard prints status and toggles an optional band row. It answers a status tool. A PostCompact hook leaves a marker.",
  "author": {
    "name": "Melodic Software",
    "email": "[email protected]"
  },
  "license": "MIT",
  "keywords": [
    "context-window",
    "mod",
    "zones",
    "context-degradation",
    "session",
    "hooks"
  ],
  "userConfig": {
    "context_guard_hooks_enabled": {
      "type": "boolean",
      "title": "Zone notices and compaction marker",
      "description": "Runs the module's zone lines and toasts and the PostCompact marker hook. On by default; off, none of them acts. Snapshot writes continue either way.",
      "default": true
    },
    "model_notices": {
      "type": "boolean",
      "title": "Model notices",
      "description": "Sends Claude one line when the session crosses into a worse context zone, approaches a boundary, or passes a zones.json threshold, and restates the zone after a compaction, a resume or a reload. Off by default; the toast, transcript line, band row, status tool and snapshot work either way.",
      "default": false
    },
    "zone_report_mode": {
      "type": "string",
      "title": "Zone report mode",
      "description": "Acts only with model_notices on. automatic (default) sends the lines to Claude; operator holds them in a turn a person typed and offers the person a ready-made prompt and a notice row when the turn ends. Headless, loop and schedule turns get automatic lines either way.",
      "default": "automatic",
      "options": [
        "automatic",
   

Read the full file on GitHub · 61 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. 2d ago Changed 62c4336ac9ff
  2. 4d ago Changed · -26 lines dbe6bece8e7e
  3. 6d ago Changed b78b6105e90f
  4. 7d ago Changed d510ce98e501
  5. 8d ago Changed 065211023886
  6. 11d ago Changed · +44 lines 85360b048bf0
  7. 12d ago Changed · -1 lines 661bfc6669d6
  8. 13d ago Changed · +3 lines 1e511ea3e38b
  9. 14d ago Changed 364d7f6857bc
  10. 15d ago First seen · 41 lines scan A e483f770b3c3

Subscribe to this mod's changes

context-guard is a plugin published in the GitHub repository melodic-software/claude-code-plugins (25 stars, last pushed today), licensed MIT. Its token cost is not measured: this kind of file is read by the harness, not the model. 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.