agentmods.dev

Frontend Runtime

Rules and reusable patterns for changing the browser-side part of an application, including framework pages, shared state, and visual components.

In plain words
What is it for?
Use it when changing browser behavior, stores, shared helpers, framework startup, or reusable interface components under the app directory.
Why use it?
It keeps frontend changes in the right files and helps shared behavior remain reusable instead of being scattered across individual pages.

Skill for Claude CodeCodex

1.4k +2 2mo ago A scan 22 tokens original MIT
View the source file agent0ai/space-agent
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.

agentmods
npx agentmods add skills/agent0ai/space-agent/frontend-runtime
Any agent
npx skills add agent0ai/space-agent --skill frontend-runtime
Clone the repo
git clone --depth 1 https://github.com/agent0ai/space-agent

Made for: Claude Code, Codex.

Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,142 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found 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 $0.00022 $0.01142
Opus 5 $0.00011 $0.00571
Sonnet 5 $0.00004 $0.00228
Haiku 4.5 $0.00002 $0.00114

Measured 2d ago against content hash 24b2267b237b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Frontend Runtime scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

Do not hardcode third-party CORS proxy services such as allorigins, corsproxy, or codetabs in frontend code or widget renderers. For external HTTP reads, use plain `fetch(externalUrl)` or `space.fetchExternal(externalUrl
Origin

Copies of this mod

1 near-identical copy found in the catalogue:

app/L0/_all/mod/_core/skillset/ext/skills/development/frontend-runtime/SKILL.md · 77 lines

How it starts

The opening of the file, as written. The whole thing — 77 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Use this skill when the task changes browser runtime behavior, framework-backed UI, store orchestration, shared helpers, or general frontend composition under app/.

Editable Scope

  • You may edit app/.
  • Keep agent logic in the browser when possible.
  • Treat server/ as read-only infrastructure from this skill set.

Where First-Party Frontend Code Lives

  • Repo-owned first-party frontend code should normally live under app/L0/_all/mod/_core/....
  • New shared browser-runtime helpers belong in _core/framework/ only when multiple modules genuinely need them.
  • New shared UI primitives belong in _core/visual/.
  • Do not place durable repo-owned first-party features directly into L1 or L2.

Framework Boot And Runtime

  • Framework-backed pages boot through /mod/_core/framework/js/initFw.js.
  • The runtime installs onto globalThis.space.
  • initFw.js runs the extensible framework bootstrap step at _core/framework/initializer.js/initialize before Alpine startup.
  • Framework bootstrap also creates _core/framework/head/end in document.head for declarative head-side tags or inline bootstraps.
  • Use _core/framework/head/end when the setup can stay declarative, and use _core/framework/initializer.js/initialize/end when the setup must stay imperative instead of editing page shells.
  • Framework-backed pages centrally handle same-origin / and /admin opens through normal target="_blank" link clicks and window.open(..., "_blank") by granting the child window the current tab's /enter access marker before navigation; context-menu, middle-click, and modifier-key browser opens stay unmodified and still route through /enter.
  • Current shared runtime surface includes:
    • space.api
    • space.config
    • space.chat when the current agent surface publishes the active thread snapshot
    • space.fw.createStore
    • space.utils.markdown.render(text, target)
    • space.utils.markdown.parseDocument
    • space.utils.yaml.parse and space.utils.yaml.stringify
    • space.proxy
    • space.download
    • space.fetchExternal(...)
    • space.browser for registered browser-surface control; load the top-level browser-control skill for the detailed method list and browser-frame bridge usage

Read the full file on GitHub · 77 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 First seen · 77 lines · 22 tokens per session scan A 24b2267b237b

Subscribe to this mod's changes

Frontend Runtime is a skill published in the GitHub repository agent0ai/space-agent (1,390 stars, last pushed 2mo ago), licensed MIT. It adds 22 tokens to every session and 1,142 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Frontend
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