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 agentmods add skills/usefulsoftwareco/executor/wrdn-effect-atom-optimisticnpx skills add UsefulSoftwareCo/executor --skill wrdn-effect-atom-optimisticgit clone --depth 1 https://github.com/UsefulSoftwareCo/executorWhat 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 | $0.00102 | $0.02628 |
| Opus 5 | $0.00051 | $0.01314 |
| Sonnet 5 | $0.00020 | $0.00526 |
| Haiku 4.5 | $0.00010 | $0.00263 |
Grade A, and why
wrdn-effect-atom-optimistic 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 yesterday.
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.
Copies of this mod
1 near-identical copy found in the catalogue:
- wrdn-effect-atom-optimistic — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 175 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You audit React code in this repo for one thing: did the author roll their own optimistic-update layer on top of an effect-atom query atom instead of using Atom.optimistic / Atom.optimisticFn?
This is not a security skill. It is a correctness skill. The hand-rolled patterns have a known race condition: concurrent mutations on the same row stomp each other's done() calls and the UI flickers back to a stale server value. The fix is the effect-atom primitives, which track transitions and refresh authoritatively. The repo already migrated policies and codified the pattern at .skills/effect-atom-optimistic-updates/SKILL.md.
Trace. Do not pattern-match a useState and call it a day. The signal is "this state is tracking an in-flight mutation alongside an effect-atom query," not "this component uses local state."
Trace before reporting
- Find the mutation. Is the component calling
useAtomSet(<somethingMutation>)frompackages/react/src/api/atoms.tsx? If not, this skill does not apply. - Find the read. Is the same component or its parent reading the matching list via
useAtomValue(<sameThingAtom>(scopeId))? If yes, the optimistic substitute exists or should exist. - Find the bookkeeping. Look for any of these alongside the mutation call:
useState,useReducer,useRefholding "pending" / "placeholder" / "in-flight" / "optimistic" values keyed by row idAtom.makeof a list / map / set of pending entries, in the component or inpackages/react/src/api/optimistic.tsx- Calls into
usePendingResource,usePoliciesWithPending,usePendingPolicies,mergePending, or any helper named like that try { await doMutate(...) } finally { placeholder.done() }shapes- Manual id minting (
pending-${...},crypto.randomUUID) in the page-level handler rather than inside anoptimisticFnreducer
- Confirm the optimistic atom exists or is missing. Open
packages/react/src/api/atoms.tsxand check for<thing>OptimisticAtom = Atom.family(scopeId => Atom.optimistic(<thing>Atom(scopeId))). If a sibling resource (sources, secrets, policies) has the optimistic wrapper and this one doesn't, the bug is the missing wrapper plus the hand-rolled substitute. - Check for grandfathered code.
usePendingSources,useSourcesWithPending,useConnectionsWithPendingRemovals, andusePendingConnectionRemovalsinpackages/react/src/api/optimistic.tsxare legacy. New code should not extend them. Their continued existence is not a finding by itself; new consumers or new entries inPendingResourceare.
When the trace cannot resolve with the files at hand, drop the finding.
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.
- yesterday First seen · 175 lines · 102 tokens per session scan A e2c56533f48a
wrdn-effect-atom-optimistic is a skill published in the GitHub repository UsefulSoftwareCo/executor (3,466 stars, last pushed yesterday), licensed MIT. It adds 102 tokens to every session and 2,628 once invoked, about $0.0005 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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