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.
npx skills add ariaramin/flutter-skills --skill flutter-motion-engineeringgit clone --depth 1 https://github.com/ariaramin/flutter-skillsWrote 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/ariaramin/flutter-skills/flutter-motion-engineering)<a href="https://agentmods.dev/skills/ariaramin/flutter-skills/flutter-motion-engineering"><img src="https://agentmods.dev/badge/skills/ariaramin/flutter-skills/flutter-motion-engineering/github.svg" alt="Measured on agentmods" height="20"></a>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.
<a href="https://agentmods.dev/skills/ariaramin/flutter-skills/flutter-motion-engineering"><img src="https://agentmods.dev/badge/skills/ariaramin/flutter-skills/flutter-motion-engineering.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00115 | $0.08243 |
| Opus 5.5 | $0.00046 | $0.03297 |
| Sonnet 5.5 | $0.00023 | $0.01649 |
| Haiku 4.5 | $0.00012 | $0.00824 |
Grade A, and why
flutter-motion-engineering 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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 372 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Flutter Motion Engineering
Purpose and evidence policy
Engineer motion that communicates state, follows input, survives interruption, and delivers consistent frames. Treat Apple quality as continuity, restraint, and responsiveness, not an instruction to copy iOS styling onto every platform. Accessibility and correctness are acceptance gates, never optional performance tradeoffs.
Evidence labels used below: D = documented framework behavior; P = platform/version-specific guidance; E = engineering recommendation or inference. Selection tables and validation procedures are E unless stated otherwise. Distinguish confirmed defects, measured bottlenecks, plausible risks, and optional refinements in reviews.
Check flutter --version --machine, SDK constraints, lockfiles, and the actual renderer before applying version-sensitive advice. Official documentation is rolling: some pages still identify Flutter 3.44.7 while individual sections describe 3.47; API footers can show 0.0.0. Use the installed SDK source or a matching release tag to resolve conflicts. Do not infer a minimum supported version from a rolling API page.
Bundled reference routing
Read the core workflow first, then load only the supporting material required for the task.
| Task | Reference |
|---|---|
| Gesture state, velocity, retargeting, geometry changes, route ownership | Interaction protocols |
| Baseline capture, stage diagnosis, rendering experiments, evidence reporting | Profiling playbook |
| Runnable examples, regression coverage, integration gates, validation limits | Testing and examples |
The examples are a small Flutter test package, not an application template. Reuse the host project's architecture and tokens instead of copying an entire new motion layer.
Implementation workflow
- Inspect repository rules, affected widgets and every caller, route ownership, state management, tokens, accessibility, heavy content, and existing tests. Preserve unrelated changes.
- State the interaction: what changes, what relationship motion explains, who owns the target state, and whether input can interrupt it. Classify as decorative, state-driven, navigational, gesture-driven, or physics-driven.
- Define forward, reverse, cancellation, rapid retargeting, reduced motion, focus, hit testing, and target-platform behavior before choosing APIs.
- Reuse existing primitives and platform widgets. Choose the smallest mechanism that satisfies those behaviors; no animation is valid when motion adds no meaning.
- Keep interpolation local to presentation. Implement without per-frame business events or expensive synchronous work.
- Test behavior and lifecycle; profile the representative interaction; identify the expensive stage; change one relevant mechanism and re-profile.
- Report changed behavior, checks actually run, measured results, and remaining device/platform coverage. Never label an animation optimized from source inspection alone.
What ships with it
9 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.
- references/examples/lib/motion_fade_transition.dart 316 B
- references/examples/lib/motion_translation.dart 542 B
- references/examples/lib/spring_handoff.dart 1.3 KB
- references/examples/lib/spring_offset.dart 1.7 KB
- references/examples/pubspec.yaml 175 B
- references/examples/test/motion_test.dart 6.1 KB
- references/interaction-protocols.md 7.9 KB
- references/profiling-playbook.md 7.6 KB
- references/testing-and-examples.md 4.6 KB
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.
- 6d ago First seen · 372 lines · 115 tokens per session scan A 10e18ecca7a7
flutter-motion-engineering is a skill published in the GitHub repository ariaramin/flutter-skills (6 stars, last pushed 7d ago), licensed MIT. It adds 115 tokens to every session and 8,243 once invoked, about $0.0005 per session on Opus 5.5. 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 2026-10-11.
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