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 rcosteira79/android-skills --skill rxjava-migrationgit clone --depth 1 https://github.com/rcosteira79/android-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/rcosteira79/android-skills/rxjava-migration)<a href="https://agentmods.dev/skills/rcosteira79/android-skills/rxjava-migration"><img src="https://agentmods.dev/badge/skills/rcosteira79/android-skills/rxjava-migration/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/rcosteira79/android-skills/rxjava-migration"><img src="https://agentmods.dev/badge/skills/rcosteira79/android-skills/rxjava-migration.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00024 | $0.01226 |
| Opus 5.5 | $0.00010 | $0.00490 |
| Sonnet 5.5 | $0.00005 | $0.00245 |
| Haiku 4.5 | $0.00002 | $0.00123 |
Grade A, and why
rxjava-migration 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 1mo 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 — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.
RxJava Migration
Migrate RxJava to Kotlin coroutines/flows incrementally. Only invoke this skill when the user explicitly asks to migrate RxJava code. Simple cases map directly; complex cases need a strategy and user input before any code is written.
Step 1: Complexity gate
Classify before writing any migrated code. A chain is Complex if ANY of: nested flatMap/switchMap with an inner Single/Observable; a custom Scheduler; complex error recovery (retryWhen, backoff, retry counts); multi-source zip/combineLatest (3+ sources); Flowable with an explicit backpressure strategy; a Subject shared across classes; or an unclear API return type. Any single Complex criterion makes the whole chain Complex — a two-operator chain with retryWhen is Complex.
Always confirm what each called API returns before migrating — do not assume. A leaf you think is migrated may still return Single/Observable.
Type mapping (state it explicitly — don't silently transform)
| RxJava | Coroutines/Flow |
|---|---|
Observable<T> / Flowable<T> |
Flow<T> (Flowable: match the original backpressure with buffer() / conflate()) |
Single<T> / Maybe<T> / Completable |
suspend fun: T / T? / Unit |
PublishSubject / ReplaySubject(n) |
MutableSharedFlow(replay = 0 / n) |
BehaviorSubject<T> |
ask — MutableStateFlow vs MutableSharedFlow(replay = 1) |
BehaviorSubject — ask first: StateFlow always has a current value (needs an initial, exposes .value, replays it to new collectors); SharedFlow(replay = 1) also replays the last emission but has no .value and no initial-value requirement. "Do you always have an initial value and need .value access, or is the stream sometimes empty at start?"
Schedulers and the observeOn shift
Schedulers.io() → Dispatchers.IO, computation() → Default, mainThread() → Main, single() → newSingleThreadContext(...), newThread() → IO (per-task thread spawning isn't idiomatic in coroutines).
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.
- 1mo ago First seen · 72 lines · 24 tokens per session scan A 6f5b8d0c6c5c
rxjava-migration is a skill published in the GitHub repository rcosteira79/android-skills (159 stars, last pushed 1mo ago), licensed MIT. It adds 24 tokens to every session and 1,226 once invoked, about $0.0001 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 2026-08-30.
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