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/taivop/marketplace/esternpx skills add taivop/marketplace --skill estergit clone --depth 1 https://github.com/taivop/marketplaceWrote 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/taivop/marketplace/ester)<a href="https://agentmods.dev/skills/taivop/marketplace/ester"><img src="https://agentmods.dev/badge/skills/taivop/marketplace/ester.svg" alt="Measured on agentmods" 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 | $0.00084 | $0.01375 |
| Opus 5 | $0.00042 | $0.00687 |
| Sonnet 5 | $0.00017 | $0.00275 |
| Haiku 4.5 | $0.00008 | $0.00137 |
Grade A, and why
ester scanned grade A with 1 finding 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 5d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
Search the Estonian unified library catalog (ESTER) to find books and check their availability at specific branches. No public API — uses curl + HTML parsing. How it starts
The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.
ESTER Library Catalog Search
Search the Estonian unified library catalog (ESTER) to find books and check their availability at specific branches. No public API — uses curl + HTML parsing.
Parser scripts are in this skill directory (relative to SKILL.md).
Workflow
1. Search for books
curl -s "https://www.ester.ee/search~S1*est/X?searchtype=X&searcharg=QUERY&searchscope=SCOPE&SORT=DZ&extended=0&SUBMIT=OTSI" \
| python3 SKILL_DIR/parse_search.py
Replace QUERY with URL-encoded search terms (ä=%C3%A4, ö=%C3%B6, ü=%C3%BC, õ=%C3%B5, spaces=+).
Search types (replace X in both URL path and searchtype=):
| Code | Field |
|---|---|
X |
Keyword (all fields) — default |
i |
ISBN/ISSN |
Use keyword (X) for title and author queries too — it handles them well. Do not use searchtype=t (title) or searchtype=a (author): ESTER returns a browse-heading index page for those, not a results list, and the parser will report 0 results even when matches exist.
searchscope values:
| Scope | Library |
|---|---|
| 1 | All libraries (default) |
| 7 | Eesti Rahvusraamatukogu (National Library) |
| 8 | Tallinna Raamatukogud / TlnRK (all Tallinn public library branches) |
| 15 | TLÜ Akadeemiline Raamatukogu |
| 55 | Tartu Linnaraamatukogu |
| 58 | Tartu Ülikooli raamatukogud |
Output: JSON with total count and results array of {id, title}. If an ISBN search redirects directly to a record page, output includes "direct_record": true.
Pagination: 50 results per page. Add &startnum=51 for page 2.
2. Get holdings for a book
Step 1 — Fetch the record page and check for truncation:
curl -s "https://www.ester.ee/record=b{RECORD_ID}~S1*est" \
| python3 SKILL_DIR/parse_record.py
Step 2 — If output contains "truncated": true, fetch the full holdings using the full_holdings_url from the output:
curl -s "FULL_HOLDINGS_URL" \
| python3 SKILL_DIR/parse_record.py
What ships with it
3 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.
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.
- 5d ago First seen · 121 lines · 84 tokens per session scan A 60c42ba039e3
ester is a skill published in the GitHub repository taivop/marketplace (17 stars, last pushed 5d ago), licensed MIT. It adds 84 tokens to every session and 1,375 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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