ECC is a toolkit that organizes and improves how coding agents work through skills, memory, security checks, research practices, and related extensions. It is for developers using agents such as Claude Code, Codex, OpenCode, and Cursor.
Borrowing it
Nothing to install: this file belongs to affaan-m/ECC. 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/affaan-m/ECC/main/.agents/skills/plan-canvas/SKILL.mdgit clone --depth 1 https://github.com/affaan-m/ECCWrote 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/affaan-m/ecc/plan-canvas)<a href="https://agentmods.dev/skills/affaan-m/ecc/plan-canvas"><img src="https://agentmods.dev/badge/skills/affaan-m/ecc/plan-canvas.svg" alt="Measured on agentmods" height="20"></a>- Socket pass
- Snyk fail
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 | $0.00059 | $0.02112 |
| Opus 5 | $0.00030 | $0.01056 |
| Sonnet 5 | $0.00012 | $0.00422 |
| Haiku 4.5 | $0.00006 | $0.00211 |
Grade A, and why
plan-canvas 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 7d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- plan-canvas — 95% identical, 1 lines differ
How it starts
The opening of the file, as written. The whole thing — 196 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Plan Canvas
Review loop for plans and visual artifacts: you write the artifact, the human reviews it in the browser — annotating the exact element they mean, chatting, and delivering an Approve plan / Request changes verdict — while you block on a single CLI call that returns their feedback as JSON.
Inspired by lavish-axi; rebuilt
ECC-native around the /plan confirmation gate, with zero dependencies.
When to Use
- You just wrote a plan artifact (
.claude/plans/*.plan.mdfrom/plan) and need the CONFIRM/approve decision — the canvas verdict replaces a typed "yes/proceed". - The user should point at what to change: reviewing designs, comparisons,
reports, or any local
.md/.htmlartifact. - The user asks for
/plan-canvas, a visual review, or "open it in the browser".
Do NOT use for: code review of diffs (/code-review), running web apps, or
remote URLs. The canvas serves local artifact files only.
How It Works
Invoke the CLI as ecc-plan-canvas — the bin shipped by the ecc-universal
package (on PATH after a global/plugin install; node "$CLAUDE_PLUGIN_ROOT/scripts/plan-canvas.js"
also works for plugin installs). Run it from the project you are reviewing in;
it works from any working directory. It manages a detached loopback server
(127.0.0.1:4517) shared by all sessions, keyed by artifact path — no session
ids to track.
The workflow is a plain CLI-plus-JSON loop, so it is model- and harness-agnostic:
any agent that can run a shell command and read stdout drives it the same way
(Claude Code, Codex, Cursor, Gemini, OpenCode, Copilot). Trigger it however your
harness surfaces skills — e.g. /plan-canvas in Claude Code, $plan-canvas in
Codex — or just run the ecc-plan-canvas commands directly.
# 1. Open the artifact in the user's browser (returns immediately)
ecc-plan-canvas open .claude/plans/feature.plan.md
# 2. Block until the human responds. Leave running; re-run if interrupted:
# queued feedback is never lost.
ecc-plan-canvas await .claude/plans/feature.plan.md
What ships with it
1 file 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.
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.
- 7d ago First seen · 196 lines · 59 tokens per session scan A ade500c538ee
plan-canvas is a skill published in the GitHub repository affaan-m/ECC (251,781 stars, last pushed today), licensed MIT. It adds 59 tokens to every session and 2,112 once invoked, about $0.0003 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 2026-08-30.
Other skills, from other repositories
ui-verification
Runs scoped browser probes for focus, hit targets, overflow, themes, request failures, and performance attribution, with evidence linked to UI rule IDs. Use when asked to "verify this in the browser", "reproduce this finding", or "check the fix". For source audits and severity use ui-design; field metrics require RUM…
cmux-browser
Browser automation with cmux embedded webviews (not Chrome/Chromium). Use when $CMUXWORKSPACEID is set and you need to open sites, interact with pages, wait for state changes, or extract data. Snapshot/ref workflow for reliable element targeting.
blocked-page-recovery
Use when a fetch fails: 403/429, paywall, WAF, bot wall.
shogun-screenshot
A screenshot tool for getting images from a computer or web page and then cropping, resizing, or masking sensitive information. Playwright is a browser-automation tool used here to capture web pages.
memstack-development-webapp-testing
Use when the user says 'write browser tests', 'test this page', 'playwright test', 'e2e test', 'end to end test', 'browser test', 'test the UI', or needs Playwright-based browser testing for a web application. Do NOT use for unit tests, API tests, or non-browser testing.
pr-reviewer
Reviews a diff or security scope read-only using evidence-tiered findings, structural and context-error rubrics, and repository review policy. Use when asked to "review my changes", "structural review", "review for AI patterns", or "security audit". For applying fixes use tidy; for UI defects use ui-design.