Borrowing it
Nothing to install: this file belongs to Sma1lboy/rove. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/Sma1lboy/rove/main/.agents/skills/pstack/skills/principle-guard-the-context-window/SKILL.mdgit clone --depth 1 https://github.com/Sma1lboy/roveWrote 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/sma1lboy/rove/principle-guard-the-context-window)<a href="https://agentmods.dev/skills/sma1lboy/rove/principle-guard-the-context-window"><img src="https://agentmods.dev/badge/skills/sma1lboy/rove/principle-guard-the-context-window/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/sma1lboy/rove/principle-guard-the-context-window"><img src="https://agentmods.dev/badge/skills/sma1lboy/rove/principle-guard-the-context-window.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 | $0.00046 | $0.00248 |
| Opus 5.5 | $0.00018 | $0.00099 |
| Sonnet 5.5 | $0.00009 | $0.00050 |
| Haiku 4.5 | $0.00005 | $0.00025 |
Grade A, and why
principle-guard-the-context-window 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 1mo 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.
This is a copy
94% identical to principle-guard-the-context-window — 11 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
What it actually says
Guard the Context Window
The context window is finite and non-renewable within a session. Every token that enters should earn its place.
Why: Context overflow degrades reasoning quality, creates compression artifacts, and halts progress. Unlike compute or time, context spent inside a session cannot be reclaimed.
Pattern:
- Isolate large payloads. Route verbose outputs, screenshots, and large documents to subagents. The main context gets summaries, not raw data.
- Don't read what you won't use. Read selectively based on relevance. If a file isn't needed for the current task, skip it.
- Keep frequently used content inline. Templates and references used on every invocation belong in the skill file, not in separate files that cost a read each time.
- Size phases and cap scope. Limit files per phase, set turn budgets, account for mechanism costs.
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.
- 1mo ago First seen · 20 lines · 46 tokens per session scan A 0d4481c8e579
principle-guard-the-context-window is a skill published in the GitHub repository Sma1lboy/rove (180 stars, last pushed today), licensed MIT. It adds 46 tokens to every session and 248 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 94% identical to principle-guard-the-context-window, differing in 11 lines, and is treated as a copy.
Other skills, from other repositories
learner
Post-debugging knowledge extraction — captures non-obvious, codebase-specific learnings that pass quality gates. Invoke after resolving tricky bugs or discovering surprising behavior.
context-management
Strategies for managing AI agent context windows including optimization, summarization, retrieval-augmented generation, progressive disclosure, and pruning. Use when the user is hitting context limits, building long-running agents, implementing RAG, optimizing token usage, or designing systems that need to manage…
knowledge-persistence
Patterns for learning from corrections, capturing instincts, extracting stable patterns, and building cross-session knowledge. Use when the user corrects you, when you discover a recurring pattern, or when insights should persist beyond the current session.
memory-patterns
Patterns for structuring MEMORY.md and topic-based memory files for Claude Code persistent memory. Use when the user asks about remembering things across sessions, wants to organize project knowledge, or needs guidance on what to save vs not save.
principle-guard-the-context-window
Apply when context is filling up: large outputs, long files, repeated reads, fan-out planning. Route bulk to subagents; keep summaries in the main thread, not raw payloads.
agents-skills-feedback-loop
Adds per-skill learnings loops for dated patterns, mistakes, and domain facts. Use when wiring skill memory, consolidation, or drift audits.