duckdb

duckdb is a skill for Claude Code, Codex from eSlider/2dph. It costs 76 tokens per session (436 once invoked), scanned A, original, MIT.

A coding guide for using DuckDB inside Go programs to analyze column-based data such as CSV, JSON, JSONL, and Parquet files. DuckDB is an embedded database suited to scans, counts, grouping, and quantiles.

In plain words
What is it for?
Use it for SQL-based analytics over tabular data, including counts, grouped summaries, quantiles, and JSONL or Parquet scans in Go.
Why use it?
It avoids slower hand-written loops when aggregating many rows or files and keeps DuckDB separate from the project's other storage systems.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/eslider/2dph/duckdb
Any agent
npx skills add eSlider/2dph --skill duckdb
Clone the repo
git clone --depth 1 https://github.com/eSlider/2dph

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for duckdb

README.md
[![agentmods](https://agentmods.dev/badge/skills/eslider/2dph/duckdb.svg)](https://agentmods.dev/skills/eslider/2dph/duckdb)
Your own site
<a href="https://agentmods.dev/skills/eslider/2dph/duckdb"><img src="https://agentmods.dev/badge/skills/eslider/2dph/duckdb.svg" alt="Measured on agentmods" height="20"></a>
Per session 76 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 436 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00076 $0.00436
Opus 5 $0.00038 $0.00218
Sonnet 5 $0.00015 $0.00087
Haiku 4.5 $0.00008 $0.00044

Measured 3d ago against content hash 3fd378e2c567, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

duckdb 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 3d 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.

skills/duckdb/SKILL.md · 39 lines

What it actually says

duckdb-go

Use https://github.com/duckdb/duckdb-go where it makes sense to get better performance in code.

In-process DuckDB (pkg/duckdb, database/sql driver duckdb). Vectorized SQL over tables, JSONL, CSV, Parquet. CGO with bundled libs (linux/darwin amd64/arm64). Links with gcc/g++ (libstdc++), not Zig. D21 Zig (bin/cgo/zcc) is Ladybug/tokenizers only. After eval "$(bin/cgo/zig env)":

CC=gcc CXX=g++ CGO_CFLAGS= CGO_LDFLAGS= ./bin/jsonl/stats.go <<< '[1,2,3,4,5]'
CC=gcc CXX=g++ CGO_CFLAGS= CGO_LDFLAGS= go test ./pkg/duckdb
Store Job
Ladybug graph + FTS + HNSW (facts/info)
modernc sqlite web-search KV cache + throttle
duckdb-go OLAP: quantiles, counts, scans of many rows/files
mikefarah/yq small YAML/JSON/XML/CSV/TOML/HCL slice, not bulk
./bin/jsonl/stats.go <<< '[1,2,3,4,5]'
./bin/jsonl/stats.go --jsonl path/to/rows.jsonl

Do not open Ladybug through DuckDB. Do not put secrets or client PII into DuckDB files under the repo.

Changes

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.

  1. 3d ago First seen · 39 lines · 76 tokens per session scan A 3fd378e2c567

Subscribe to this mod's changes

duckdb is a skill published in the GitHub repository eSlider/2dph (2 stars, last pushed 4d ago), licensed MIT. It adds 76 tokens to every session and 436 once invoked, about $0.0004 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 2026-08-31.

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