1c-ssl-skills: Skill for Claude Code

.agents/skills/context-compression/SKILL.md

context-compression is a skill for Claude Code, Codex from brake71/1c-ssl-skills. It costs 47 tokens per session (3,493 once invoked), scanned A, a copy of context-compression, MIT.

A method for shortening long agent conversations while preserving important decisions, changed files, risks, and next steps. The resulting summary can be used as a durable handoff to continue the work.

In plain words
What is it for?
It helps design conversation compaction, structured summaries, handoffs between agents or sessions, and ways to measure whether compression keeps the information a task needs.
Why use it?
Long sessions and large codebases can exceed a model's context window. Careful summaries reduce repeated reading while avoiding the loss of information that makes an agent forget what it did.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is brake71/1c-ssl-skills's own configuration. It tells Claude Code and Codex how to work on 1c-ssl-skills itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything 1c-ssl-skills configures →

Reuse

Borrowing it

Nothing to install: this file belongs to brake71/1c-ssl-skills. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/brake71/1c-ssl-skills/main/.agents/skills/context-compression/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/brake71/1c-ssl-skills

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 context-compression

README.md
[![agentmods](https://agentmods.dev/badge/skills/brake71/1c-ssl-skills/context-compression/github.svg)](https://agentmods.dev/skills/brake71/1c-ssl-skills/context-compression)
Your own site
<a href="https://agentmods.dev/skills/brake71/1c-ssl-skills/context-compression"><img src="https://agentmods.dev/badge/skills/brake71/1c-ssl-skills/context-compression/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-compression

Your own site · 80×15
<a href="https://agentmods.dev/skills/brake71/1c-ssl-skills/context-compression"><img src="https://agentmods.dev/badge/skills/brake71/1c-ssl-skills/context-compression.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,493 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 98% copy Near-identical to another mod 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 $0.00047 $0.03493
Opus 5.5 $0.00019 $0.01397
Sonnet 5.5 $0.00009 $0.00699
Haiku 4.5 $0.00005 $0.00349

Measured 17d ago against content hash ab4fd1e1046d, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

context-compression 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 17d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/compression_evaluator.py, tests/test_compression_evaluator.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Origin

This is a copy

98% identical to context-compression — 0 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.

.agents/skills/context-compression/SKILL.md · 282 lines

How it starts

The opening of the file, as written. The whole thing — 282 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Context Compression Strategies

When agent sessions generate millions of tokens of conversation history, compression becomes mandatory. The naive approach is aggressive compression to minimize tokens per request. The correct optimization target is tokens per task: total tokens consumed to complete a task, including re-fetching costs when compression loses critical information.

When to Activate

Activate this skill when:

  • Agent sessions exceed context window limits
  • Codebases exceed context windows (5M+ token systems)
  • Designing conversation summarization strategies
  • Debugging cases where agents "forget" what files they modified
  • Building evaluation frameworks for compression quality
  • Creating durable handoff summaries that preserve decisions, files, risks, and next actions

Do not activate this skill for adjacent work owned by other skills:

  • General token-efficiency tactics such as masking, prefix caching, or partitioning: context-optimization.
  • Diagnosing why a long context is failing before choosing a mitigation: context-degradation.
  • Writing raw outputs, logs, or plans to files without summarizing them: filesystem-context.
  • Designing long-term semantic memory across sessions: memory-systems.
  • The model deciding when and where to rewrite its own context: self-managed-context. This skill still owns what the replacement text must preserve.

Core Concepts

Context compression trades token savings against information loss. Select from three production-ready approaches based on session characteristics:

  1. Anchored Iterative Summarization: Implement this for long-running sessions where file tracking matters. Maintain structured, persistent summaries with explicit sections for session intent, file modifications, decisions, and next steps. When compression triggers, summarize only the newly-truncated span and merge with the existing summary rather than regenerating from scratch. This prevents drift that accumulates when summaries are regenerated wholesale — each regeneration risks losing details the model considers low-priority but the task requires. Structure forces preservation because dedicated sections act as checklists the summarizer must populate, catching silent information loss.

Read the full file on GitHub · 282 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 17d ago First seen · 282 lines · 47 tokens per session scan A ab4fd1e1046d

Subscribe to this mod's changes

context-compression is a skill published in the GitHub repository brake71/1c-ssl-skills (82 stars, last pushed 15d ago), licensed MIT. It adds 47 tokens to every session and 3,493 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 98% identical to context-compression, differing in 0 lines, and is treated as a copy.