Borrowing it
Nothing to install: this file belongs to tellahq/opensession. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/tellahq/opensession/main/.agents/skills/effect-ts/SKILL.mdgit clone --depth 1 https://github.com/tellahq/opensessionWrote 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/tellahq/opensession/effect-ts)<a href="https://agentmods.dev/skills/tellahq/opensession/effect-ts"><img src="https://agentmods.dev/badge/skills/tellahq/opensession/effect-ts/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/tellahq/opensession/effect-ts"><img src="https://agentmods.dev/badge/skills/tellahq/opensession/effect-ts.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 | $0.00184 | $0.03813 |
| Opus 5.5 | $0.00074 | $0.01525 |
| Sonnet 5.5 | $0.00037 | $0.00763 |
| Haiku 4.5 | $0.00018 | $0.00381 |
Grade A, and why
effect-ts 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 — 329 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Effect-TS (v4, pinned to 4.0.0-rc.112)
Every API name in this skill was checked against node_modules/effect/dist/*.d.ts
at 4.0.0-rc.112 and the Effect repository at tag [email protected]
(LLMS.md, ai-docs/src, migration/). Patterns come from the official
ai-docs and the Effect team's LLMS.md, not from third-party summaries.
Originally derived from joelhooks/effectts-skills (MIT), which targeted an
early v4 beta and still uses ServiceMap.Service, Schema.TaggedErrorClass,
Schedule.compose, and @effect/vitest-only testing. Those names do not exist
in rc.112. This copy was rewritten on 2026-09-03; the rename map below records
what changed.
Source-first rule
Never guess an Effect v4 API. v4 renamed modules between betas and the RC line still moves. Before writing or reviewing Effect code:
- Confirm the pin:
grep '"effect"' packages/core/opensession-server/package.json. - Use the repo-local mirror at
.agent-sources/effect/, checked out at the matching tag (git -C .agent-sources/effect describe --tagsmust print[email protected]). If it is missing or onmain:
The mirror is excluded throughmkdir -p .agent-sources git clone --depth 1 --branch [email protected] https://github.com/Effect-TS/effect.git .agent-sources/effect.git/info/exclude; never commit it.mainis ahead of the pin (it already hasConfig.Stringwhere rc.112 hasConfig.string), so a tag checkout is required, not optional. - Read the official guidance in this order:
LLMS.md(curated patterns),ai-docs/src/**(runnable examples),migration/*.md(v3 to v4 rename tables), thenpackages/effect/src/<Module>.tsfor signatures and JSDoc. - When a snippet here and the source disagree, the source wins. Fix the snippet.
Quick checks:
grep -n "^export declare const retry:" node_modules/effect/dist/Effect.d.ts
grep -rn "Schedule.while" .agent-sources/effect/ai-docs/src
Rename map (what older docs and skills get wrong)
What ships with it
11 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/cli.md 9.4 KB
- references/config.md 6.0 KB
- references/data-modeling.md 5.9 KB
- references/error-handling.md 6.6 KB
- references/http-clients.md 9.0 KB
- references/open-session-frontend.md 7.5 KB
- references/processes.md 7.3 KB
- references/schema-decisions.md 5.6 KB
- references/services-and-layers.md 9.8 KB
- references/setup.md 6.2 KB
- references/testing.md 9.5 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.
- 1mo ago First seen · 329 lines · 184 tokens per session scan A 99d896b8b626
effect-ts is a skill published in the GitHub repository tellahq/opensession (399 stars, last pushed today), licensed MIT. It adds 184 tokens to every session and 3,813 once invoked, about $0.0007 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 2026-09-03.
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