signals-preact-dart

signals-preact-dart is a skill for Claude Code, Codex from rodydavis/signals.dart. It costs 22 tokens per session (943 once invoked), scanned A, original, Apache-2.0.

Core guidance for reactive state in Dart using Preact Signals, a way to update dependent values and UI when data changes. It defines writable values, derived values, observers, read-only views, and grouped updates.

In plain words
What is it for?
Use it when implementing or reviewing signals, computed values, effects, read-only state, and batched updates in the preact_signals Dart package.
Why use it?
It provides consistent patterns for tracking state changes and prevents unnecessary recalculation or rendering work.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when implementing or reviewing signals, computed values, effects, read-only state, and batched updates in the preact_signals Dart package.

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Install with agentmods
npx agentmods add skills/rodydavis/signals.dart/signals-preact-dart
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.

Any agent
npx skills add rodydavis/signals.dart --skill signals-preact-dart
Clone the repo
git clone --depth 1 https://github.com/rodydavis/signals.dart

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 signals-preact-dart

README.md
[![agentmods](https://agentmods.dev/badge/skills/rodydavis/signals.dart/signals-preact-dart/github.svg)](https://agentmods.dev/skills/rodydavis/signals.dart/signals-preact-dart)
Your own site
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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 signals-preact-dart

Your own site · 80×15
<a href="https://agentmods.dev/skills/rodydavis/signals.dart/signals-preact-dart"><img src="https://agentmods.dev/badge/skills/rodydavis/signals.dart/signals-preact-dart.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 943 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00022 $0.00943
Opus 5 $0.00011 $0.00472
Sonnet 5 $0.00004 $0.00189
Haiku 4.5 $0.00002 $0.00094

Measured 13d ago against content hash 130ee1868fbe, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

signals-preact-dart 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 13d 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.

skills/signals-preact-dart/SKILL.md · 124 lines

How it starts

The opening of the file, as written. The whole thing — 124 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Preact Signals in Dart

This skill covers the core reactive programming primitives and implementation patterns of the preact_signals package.

Related File Description
signal.md Standard writeable reactive state primitive containing value accessors, mutation mechanics, and basic custom options.
computed.md Lazy, memoized read-only derived state signal tracking reactive dependencies dynamically.
effect.md Synchronous observer managing active subscription loops, dynamic dependency updates, and lifecycle teardown.
readonly.md Read-only signal views ensuring unidirectional data access flows.
batch.md Transactional state mutation blocks optimizing reactive computations and preventing rendering/recompute churn.

Core Primitives Quick Start Guide

The signals library exposes five core functions which are the building blocks to model any reactive business logic.

1. signal(initialValue)

Creates a new mutable signal container. You read a signal's value or subscribe to updates by accessing .value.

final counter = signal(0);
print(counter.value); // 0
counter.value = 1; // Mutates value and schedules dependent updates
.peek()

Reads a signal's current value without subscribing to its mutations.

final counter = signal(0);
final logCount = signal(0);

effect(() {
  print(counter.value);
  // Read using peek to avoid subscribing/triggering loop
  logCount.value = logCount.peek() + 1;
});

2. untracked(fn)

Executes a callback that reads signals without subscribing to any of them.

final counter = signal(0);
final count = signal(0);

effect(() {
  print(counter.value);
  count.value = untracked(() => count.value + 1);
});

3. computed(fn)

Combines the values of multiple signals into a lazy, memoized derived signal.

final first = signal('John');
final last = signal('Doe');
final fullName = computed(() => '${first.value} ${last.value}');
print(fullName.value); // John Doe

Read the full file on GitHub · 124 lines

Files

What ships with it

7 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. 13d ago First seen · 124 lines · 22 tokens per session scan A 130ee1868fbe

Subscribe to this mod's changes

signals-preact-dart is a skill published in the GitHub repository rodydavis/signals.dart (814 stars, last pushed 3d ago), licensed Apache-2.0. It adds 22 tokens to every session and 943 once invoked, about $0.0001 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.

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