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 ericrisco/rsc-harness --skill duckdbgit clone --depth 1 https://github.com/ericrisco/rsc-harnessWrote 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/ericrisco/rsc-harness/duckdb)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/duckdb"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/duckdb/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/ericrisco/rsc-harness/duckdb"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/duckdb.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 | $0.00085 | $0.02702 |
| Opus 5.5 | $0.00034 | $0.01081 |
| Sonnet 5.5 | $0.00017 | $0.00540 |
| Haiku 4.5 | $0.00009 | $0.00270 |
Grade C, and why
duckdb scanned grade C with 2 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.
Downloads and executes remote codehighSupply chain
curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.
curl https://install.duckdb.org | sh # or: brew install duckdb Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl https://install.duckdb.org | sh # or: brew install duckdb How it starts
The opening of the file, as written. The whole thing — 203 lines — stays where its author put it; the contents beside it link to each section on GitHub.
DuckDB — embedded columnar OLAP, no server
DuckDB is an in-process analytical (OLAP) database: it links into your process like SQLite, but stores
data column-by-column and vectorizes execution for aggregates, joins, and window functions. There is no
server, no port, no daemon — you pip install duckdb (or drop one CLI binary) and query. Its killer move
is reading Parquet/CSV/JSON/Arrow in place, without a load step, so a folder of files becomes a table.
The fact that drives every routing decision below: DuckDB is one writer, many readers, single process. It is brilliant for analysis on one machine and wrong for multi-user serving or transactional app writes.
Latest stable is v1.5.3 (released 2026-05-20). Pin the LTS line (v1.4.x; v1.4.4 LTS shipped 2026-01-26) for anything long-lived — LTS gets ~1 year of patches and a stable storage format. Use 1.5.x for greenfield exploration.
Is DuckDB the tool? (decide first)
| Your workload | Reach for |
|---|---|
| Analytics over local/remote files, one process, one writer | duckdb (this skill) |
| Many concurrent users, production query API, dashboards-as-a-service, petabyte scale | clickhouse-analytics |
| App transactional CRUD: users, orders, many small writes, FKs, connection pool | postgresdb |
| Embedded single-file transactional store / edge / sync | sqlite-turso |
| Pure SQL syntax question, engine-agnostic (window fns, CTEs) | sql |
| Similarity / embedding search as the core workflow | vector-db |
The two you will confuse most: DuckDB vs ClickHouse is embedded-single-node vs server-distributed — under ~10GB on one box DuckDB usually wins; pick ClickHouse when many people query concurrently. DuckDB vs SQLite is same niche, opposite workload — both embedded single-file, but SQLite is row-store OLTP and DuckDB is column-store OLAP. Don't run your app's writes through DuckDB.
What ships with it
5 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.
- 1mo ago First seen · 203 lines · 85 tokens per session scan C 4c0ab72c7f66
duckdb is a skill published in the GitHub repository ericrisco/rsc-harness (267 stars, last pushed 2d ago), licensed MIT. It adds 85 tokens to every session and 2,702 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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