slipstream-packages

slipstream-packages is a skill for Claude Code, Codex from devoncarew/flutter-slipstream. It costs 85 tokens per session (380 once invoked), scanned A, original, BSD-3-Clause.

A local lookup tool for Dart and Flutter packages, which are reusable code libraries downloaded through Dart’s package manager.

In plain words
What is it for?
Use it before writing Dart or Flutter code that calls an unfamiliar package, or when a package import causes a compile error or type mismatch.
Why use it?
Package APIs can change or be remembered incorrectly. It reads the exact package version installed in the project, including its available classes, functions, and parameters.

Skill for Claude CodeCodex

Part of the flutter-slipstream plugin — 3 skills shipped together

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/devoncarew/flutter-slipstream/slipstream-packages
Any agent
npx skills add devoncarew/flutter-slipstream --skill slipstream-packages
Clone the repo
git clone --depth 1 https://github.com/devoncarew/flutter-slipstream

Made for: Claude Code, Codex.

Or install flutter-slipstream, the plugin that ships this one along with the rest of its 3 skills.

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 slipstream-packages

README.md
[![agentmods](https://agentmods.dev/badge/skills/devoncarew/flutter-slipstream/slipstream-packages.svg)](https://agentmods.dev/skills/devoncarew/flutter-slipstream/slipstream-packages)
Your own site
<a href="https://agentmods.dev/skills/devoncarew/flutter-slipstream/slipstream-packages"><img src="https://agentmods.dev/badge/skills/devoncarew/flutter-slipstream/slipstream-packages.svg" alt="Measured on agentmods" height="20"></a>
Per session 85 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 380 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00085 $0.00380
Opus 5 $0.00043 $0.00190
Sonnet 5 $0.00017 $0.00076
Haiku 4.5 $0.00009 $0.00038

Measured 4d ago against content hash aab2b9c8d612, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

slipstream-packages 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 4d 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/slipstream-packages/SKILL.md · 40 lines

What it actually says

Dart Package API Lookup

Training-data summaries for pub packages are often subtly out-of-date: incorrect parameter names, missing required/optional distinctions, wrong constructor shapes, renamed or removed APIs. The packages tools read directly from the local pub cache — exact signatures, always matches pubspec.lock, no network required.

Call sequence

  1. package_summary(project_directory, package) — always start here. Returns version, entry-point import, library list, and exported name groups. Often enough to confirm the right import path and top-level names.
  2. library_stub(project_directory, package, library_uri) — full public API for one library as Dart signatures (no bodies, no private members). Use when you need exact constructor shapes, named parameter names, or return types.
  3. class_stub(project_directory, package, library_uri, class) — single class stub including inherited and mixin-contributed members. Use when you know exactly which class you need.

project_directory is the absolute path to the Dart/Flutter project (the directory containing pubspec.yaml). Run dart pub get first if .dart_tool/package_config.json is missing.

Limitation

Constants values are not shown in stubs.

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. 4d ago First seen · 40 lines · 85 tokens per session scan A aab2b9c8d612

Subscribe to this mod's changes

slipstream-packages is a skill published in the GitHub repository devoncarew/flutter-slipstream (5 stars, last pushed 17d ago), licensed BSD-3-Clause. It adds 85 tokens to every session and 380 once invoked, about $0.0004 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 2026-08-31.

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