https://github.com/blackwell-systems/gcf-codex-plugin
Codex plugin for GCF Proxy. Save 71% on MCP tool call tokens.
https://github.com/blackwell-systems/gcf-codex-plugin
ai-cost-reduction codex codex-plugin gcf llm mcp mcp-proxy token-optimization
Last synced: 7 days ago
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Codex plugin for GCF Proxy. Save 71% on MCP tool call tokens.
- Host: GitHub
- URL: https://github.com/blackwell-systems/gcf-codex-plugin
- Owner: blackwell-systems
- License: mit
- Created: 2026-06-13T20:56:49.000Z (about 1 month ago)
- Default Branch: main
- Last Pushed: 2026-06-13T21:03:33.000Z (about 1 month ago)
- Last Synced: 2026-06-13T22:25:03.578Z (about 1 month ago)
- Topics: ai-cost-reduction, codex, codex-plugin, gcf, llm, mcp, mcp-proxy, token-optimization
- Homepage: https://gcformat.com
- Size: 8.79 KB
- Stars: 0
- Watchers: 0
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
- Security: SECURITY.md
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README
# gcf-codex-plugin
Codex plugin for [GCF Proxy](https://github.com/blackwell-systems/gcf-proxy). Reduces MCP tool call token costs by 71%.
## Install
```bash
codex plugin add gcf-proxy
```
## What it does
Every MCP tool call returns JSON. This plugin wraps your MCP servers with [GCF Proxy](https://github.com/blackwell-systems/gcf-proxy), which re-encodes those JSON responses as GCF before they reach the model.
**The savings:**
| Metric | Value |
|--------|-------|
| Token reduction vs JSON | **71%** |
| Token reduction vs TOON | **25%** |
| Session dedup (warm session) | **up to 92%** |
| Comprehension accuracy | **100%** across 1,700+ LLM evaluations |
## Skills
| Skill | Description |
|-------|-------------|
| `/gcf-proxy:setup ` | Wrap any MCP server with gcf-proxy |
| `/gcf-proxy:stats` | Show token savings for the current session |
## Hooks
- **SessionStart**: Clears stale stats from previous sessions
- **Stop**: Shows notification with calls rewritten, % saved, and tokens saved
## Quick start
After installing, wrap any MCP server:
```
/gcf-proxy:setup github
```
This modifies your MCP config to route the server through gcf-proxy. The original config is preserved (disabled, with a `-raw` suffix) so you can revert anytime.
## How the savings work
1. **First call (71% savings):** GCF encodes the same structured data in 71% fewer tokens than JSON. The model reads GCF natively with 100% comprehension accuracy.
2. **Subsequent calls (up to 92%):** Session deduplication detects repeated structure. Only deltas are transmitted.
3. **Zero code changes:** The proxy wraps any MCP server. The server still outputs JSON; the proxy re-encodes before it reaches the model.
## Cost example
A team running 1,000 queries/day with GPT-5.5 ($5/MTok input):
| Format | Monthly cost | Annual cost |
|--------|-------------|-------------|
| JSON | $12,098 | $145,171 |
| GCF | $3,549 | $42,583 |
| **Savings** | **$8,549/mo** | **$102,588/yr** |
[Try the cost calculator](https://gcformat.com/calculator) with your own numbers.
## Links
- [GCF Spec](https://gcformat.com)
- [GCF Proxy](https://github.com/blackwell-systems/gcf-proxy)
- [Claude Code Plugin](https://github.com/blackwell-systems/gcf-claude-plugin)
- [Benchmarks](https://gcformat.com/guide/benchmarks.html)
- [Cost Calculator](https://gcformat.com/calculator)
## License
MIT