Workflow·Files & Storage

DuckDB Read File

Read any data file (CSV, JSON, Parquet, Avro, Excel, spatial, SQLite) or remote URL (S3, HTTPS).

You say
Buy it · $12 Read it before you buy $12 Written by duckdb · unverified publisher
Context cost
925 tokensestimated from the bundle, loaded when it triggers
Bundle
1 file · 3.7 kBtext throughout, nothing executable
Licence
MITpaid listing
Last change
no release on file
Servers it uses
Noneruns standalone

What it does

Read any data file (CSV, JSON, Parquet, Avro, Excel, spatial, SQLite) or remote URL (S3, HTTPS). Use when user references a data file, asks "what's in this file", or wants to preview/profile a dataset. Not for source code.

Installed, it changes the agent in these ways.

What this skill changes about the agent is not written down here yet. The listing was collected from its source, and the description is in its own SKILL.md.

Workflow

Runs a procedure end to end.

filesparquetcsvpreview
Filed under

Files & Storage

The skill itself

This is the whole product. A skill is instructions the model reads, so there is nothing behind the listing you cannot see first — the front matter loads with every session, and the body below it loads when the skill triggers.

SKILL.md3.7 kB · 82 lines
--- name: read-file description: > Read any data file (CSV, JSON, Parquet, Avro, Excel, spatial, SQLite) or remote URL (S3, HTTPS). Use when user references a data file, asks "what's in this file", or wants to preview/profile a dataset. Not for source code. argument-hint: <filename or URL> [question about the data] allowed-tools: Bash ---
11You are helping the user read and analyze a data file using DuckDB.
12
13Filename given: $0
14Question: ${1:-describe the data}
15
16## Step 1 — Read it
17
18RESOLVED_PATH is $0. If the user gave a bare filename (no /), resolve it to a full path with find first.
19
20Run a single DuckDB command that defines the read_any macro inline and reads the file.
21
22For **remote files**, prepend the necessary LOAD/SECRET before the macro:
23
24| Protocol | Prepend |
25|---|---|
26| https:// / http:// | LOAD httpfs; |
27| s3:// | LOAD httpfs; CREATE SECRET (TYPE S3, PROVIDER credential_chain); |
28| gs:// / gcs:// | LOAD httpfs; CREATE SECRET (TYPE GCS, PROVIDER credential_chain); |
29| az:// / azure:// / abfss:// | LOAD httpfs; LOAD azure; CREATE SECRET (TYPE AZURE, PROVIDER credential_chain); |
30
31For **local files**, no prefix needed.
32
33```bash
34duckdb -csv -c "
35CREATE OR REPLACE MACRO read_any(file_name) AS TABLE
36 WITH json_case AS (FROM read_json_auto(file_name))
37 , csv_case AS (FROM read_csv(file_name))
38 , parquet_case AS (FROM read_parquet(file_name))
39 , avro_case AS (FROM read_avro(file_name))
40 , blob_case AS (FROM read_blob(file_name))
41 , spatial_case AS (FROM st_read(file_name))
42 , excel_case AS (FROM read_xlsx(file_name))
43 , sqlite_case AS (FROM sqlite_scan(file_name, (SELECT name FROM sqlite_master(file_name) LIMIT 1)))
44 , ipynb_case AS (
45 WITH nb AS (FROM read_json_auto(file_name))
46 SELECT cell_idx, cell.cell_type,
47 array_to_string(cell.source, '') AS source,
48 cell.execution_count
49 FROM nb, UNNEST(cells) WITH ORDINALITY AS t(cell, cell_idx)
50 ORDER BY cell_idx
51 )
52 FROM query_table(
53 CASE
54 WHEN file_name ILIKE '%.json' OR file_name ILIKE '%.jsonl' OR file_name ILIKE '%.ndjson' OR file_name ILIKE '%.geojson' OR file_name ILIKE '%.geojsonl' OR file_name ILIKE '%.har' THEN 'json_case'
55 WHEN file_name ILIKE '%.csv' OR file_name ILIKE '%.tsv' OR file_name ILIKE '%.tab' OR file_name ILIKE '%.txt' THEN 'csv_case'
56 WHEN file_name ILIKE '%.parquet' OR file_name ILIKE '%.pq' THEN 'parquet_case'
57 WHEN file_name ILIKE '%.avro' THEN 'avro_case'
58 WHEN file_name ILIKE '%.xlsx' OR file_name ILIKE '%.xls' THEN 'excel_case'
59 WHEN file_name ILIKE '%.shp' OR file_name ILIKE '%.gpkg' OR file_name ILIKE '%.fgb' OR file_name ILIKE '%.kml' THEN 'spatial_case'
60 WHEN file_name ILIKE '%.ipynb' THEN 'ipynb_case'
61 WHEN file_name ILIKE '%.db' OR file_name ILIKE '%.sqlite' OR file_name ILIKE '%.sqlite3' THEN 'sqlite_case'
62 ELSE 'blob_case'
63 END
64 );
65
66DESCRIBE FROM read_any('RESOLVED_PATH');
67SELECT count(*) AS row_count FROM read_any('RESOLVED_PATH');
68FROM read_any('RESOLVED_PATH') LIMIT 20;
69"
70```
71
72**If this fails:**
73- **duckdb: command not found** → invoke /duckdb-skills:install-duckdb and retry.
74- **Missing extension** (e.g. spatial files, xlsx, sqlite) → retry with INSTALL spatial; LOAD spatial; or INSTALL sqlite_scanner; LOAD sqlite_scanner; prepended before the macro.
75- **Wrong reader / parse error** → use the correct read_* function directly instead of read_any.
76
77## Step 2 — Answer
78
79Using the schema, row count, and sample rows, answer:
80
81${1:-describe the data: summarize column types, row count, and any notable patterns.}
82
In the file
SKILL.md486 words
Files1
LicenceMIT
Why you can read it

Nothing in a skill executes. The client loads the text and the model follows it, so a skill can be audited the way a runbook is — by reading it.

What it costs in context

Skills are not billed by the call. They are paid for in context: every token the instructions occupy is a token your code, your diff and your conversation cannot use. Here is what this one takes and when it takes it.

≈90
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
835
on trigger
The instruction body, read only when the skill fires.
0.46%
of a 200k window
Ten skills this size would take about 5% of the window before you open a file.
050k100k150k200k context window

925 tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Small enough to keep loaded permanently without thinking about it.

Servers bill, skills cost

A server charges by the month. A skill charges once per session, in context, and then keeps charging it for as long as the session lives.

Before and after

The same question, put to the same model twice: once as it comes, and once with these instructions loaded.

No worked example has been published for this skill yet.

Adoption
Installsnone yet
Ratingno reviews yet

The procedure it runs

The procedure has not been published here. It is in the skill’s own SKILL.md, which its author has not sent to the marketplace yet.

Prose, not code

These steps are written for a model to follow, not executed by a runtime. It can still be told to skip one, and it will say so when it does.

Servers it uses

None. This skill calls no MCP servers at all.

Everything it needs is in the instructions, so it works in a project with nothing connected — the model reads the file and changes how it works with what it can already reach.

It writes no files and reaches no network. All it changes is how the model reasons and writes.

What it asks for
Writes filesno
Network accessno

Read from the allowed-tools line of this skill’s own SKILL.md. A skill grants no permissions of its own — it can only ask for tools your client already has.

What it will not do

Every skill is narrow, and the useful ones say where they stop. These are the jobs this one is the wrong tool for.

What this skill is not for has not been published here. Nothing is implied by that: it is a section the author has not filled in.

What is in the bundle

1 file, 3.7 kB on disk. A bundle is text throughout: the instructions the model reads, plus the templates it fills in.

  • SKILL.md3.7 kB
What is not in it

No dependencies and nothing executable: a skill is text the agent reads, so the bundle is 1 file you can review in full before installing. The MIT licence covers the templates and examples as well as the instructions.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

$12 once
DuckDB Read File · MIT · duckdb
one-time
Price$12 once
LicenceMIT — the author’s, unchanged by this purchase
Paid throughStripe, once, on the card you add at the checkout
Keeps workingfor good — the files are yours once they are on disk
Updatesevery update its author ships, delivered through this account

You can read the whole bundle before paying — the SKILL.md above is the product, not a preview of it. What the money buys is the delivery: the folder packaged and handed to your machine by key, every update its author ships, and our support if it does not do what this listing says. The terms of use are MIT, set by the author and unchanged by buying it here.

Payment runs through Stripe, on a page like this one rather than a redirect. Once there is an account it joins the same mcprush invoice as everything else you run, so there is never a second card to enter.

Which clients pick it up on their own

A skill is a folder of text. A client with a skills folder reads it without being told; everywhere else the same text works, it is just handed to the model rather than found.

Claude Code.claude/skills/
Claude Desktop
ChatGPT
Cursor.cursor/skills/
VS Code.github/skills/
Codex CLI.agents/skills/
Gemini CLI.gemini/skills/
Grok.grok/skills/
Zed.agents/skills/
Windsurf.windsurf/skills/
Agent SDK.claude/skills/
HTTP / API
This release
Versionnot versioned
Publishedno release date on file
Price$12
Referenceduckdb/duckdb-read-file

Versions

Its author publishes no version number, so there is nothing here to pin to: what you install is the folder as it stands today. Instructions change more often than APIs do — a skill can be rewritten entirely without anything it depends on moving.

v
  • No earlier releases have been published to the marketplace.
Pinning

Nothing to pin to: this skill carries no version number of its own. What you install is what the folder holds on the day you install it.

Reviews

no reviews yet · no installs yet

Nobody has reviewed this skill yet. The rating is the mean of the reviews written here, so there is none until somebody writes the first.

Who can post

Only accounts that have had the skill installed for fourteen days, so a review is written after living with it rather than after reading it. Publishers may reply once.

Publisher
Servers0