What is wren-generate-mdl?

A tool for creating a Wren MDL manifest from an existing database. An MDL manifest is Wren’s description of the data models and fields it can use for analysis.

Use it when onboarding a data source, setting up a new Wren project, or scaffolding an MDL manifest from an existing database.

It discovers the database schema through Wren’s server, so local database drivers are not needed. The database connection must be configured in Wren’s web interface first.

wren-generate-mdl — Skill for Claude Code by Canner/wren-engine

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.

Any agent

npx skills add Canner/wren-engine --skill wren-generate-mdl

Clone the repo

git clone --depth 1 https://github.com/Canner/wren-engine

Made for: Claude Code.

Or install wren, the plugin that ships this one along with the rest of its 8 skills.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/canner/wren-engine/wren-generate-mdl/github.svg)](https://agentmods.dev/skills/canner/wren-engine/wren-generate-mdl)

Your own site

<a href="https://agentmods.dev/skills/canner/wren-engine/wren-generate-mdl"><img src="https://agentmods.dev/badge/skills/canner/wren-engine/wren-generate-mdl/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/canner/wren-engine/wren-generate-mdl"><img src="https://agentmods.dev/badge/skills/canner/wren-engine/wren-generate-mdl.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 61 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,862 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00061	$0.01862
Opus 5.5	$0.00024	$0.00745
Sonnet 5.5	$0.00012	$0.00372
Haiku 4.5	$0.00006	$0.00186

Measured 2mo ago against content hash 7dc8857bd651, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

wren-generate-mdl 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 2mo 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.

> **Connection info can ONLY be configured through the Web UI at `http://localhost:9001`.** Do not attempt to set connection info programmatically via ibis-server API calls, curl, or any other method. The ibis-server doe

skills-archive/wren-generate-mdl/SKILL.md · 215 lines

How it starts

The opening of the file, as written. The whole thing — 215 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Generate Wren MDL

Version check

Silently fetch https://raw.githubusercontent.com/Canner/wren-engine/main/skills/versions.json. Compare the wren-generate-mdl key with this skill's version (from the frontmatter above). If the remote version is newer, notify the user before proceeding:

A newer version of the wren-generate-mdl skill is available. Update with:
npx skills add Canner/wren-engine --skill wren-generate-mdl --agent claude-code

Then continue with the workflow below regardless of update status.

Generates a Wren MDL manifest by using ibis-server to introspect the database schema — no local database drivers required. All schema discovery goes through ibis-server, which already has drivers for all supported data sources.

Workflow

Follow these steps in order. Do not skip steps or ask unnecessary questions between them.

Step 1 — Verify connection and choose data source

Connection info can ONLY be configured through the Web UI at http://localhost:9001. Do not attempt to set connection info programmatically via ibis-server API calls, curl, or any other method. The ibis-server does not expose a public API for writing connection info — only the Web UI can do this.

Confirm the MCP server has a working connection before proceeding:

health_check()

If the health check fails, or if the user has not yet configured a connection, direct them to the Web UI at http://localhost:9001 to enter their data source credentials. Wait for the user to confirm the connection is saved before continuing.

Ask the user for:

Data source type (e.g. POSTGRES, BIGQUERY, SNOWFLAKE, …) — needed to set dataSource in the MDL
Schema filter (optional) — if the database has many schemas, ask which schema(s) to include

After this step you will have:

data_source: e.g. "POSTGRES"
Optional schema_filter: used to narrow down results in subsequent steps

Step 2 — Fetch table schema

list_remote_tables()

Read the full file on GitHub · 215 lines

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.

2mo ago First seen · 215 lines · 61 tokens per session scan A 7dc8857bd651

Subscribe to this mod's changes

wren-generate-mdl is a skill published in the GitHub repository Canner/wren-engine (661 stars, last pushed 6mo ago), licensed Apache-2.0. It adds 61 tokens to every session and 1,862 once invoked, about $0.0002 per session on Opus 5.5. 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.

Analytics and metrics Databases business-intelligence data data lake data-analysis data-analytics data-warehouse

wren-generate-mdl next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
wren-generate-mdlCanner/wren-engine	Skill	661	6mo ago	Apache-2.0	A	61	Claude Code
malloy-lookml-reviewmalloydata/publisher	Skill	130	yesterday	MIT	A	58	Claude Code, Codex
ecommerce-data-warehousefinsilabs/awesome-ecommerce-skills	Skill	63	14d ago	MIT	A	35	Claude Code, Codex
effective-dbt-sqllightdash/lightdash	Skill	6.2k	yesterday	none	A	0	Claude Code, Codex
analytical-databases-expertpersonamanagmentlayer/pcl	Skill	44	11d ago	Apache-2.0	A	100	Claude Code
business-intelligence-expertpersonamanagmentlayer/pcl	Skill	44	11d ago	Apache-2.0	A	64	Claude Code
alibabacloud-data-agent-skillaliyun/data-agent-skill	Skill	57	4d ago	none	A	159	Claude Code, Codex

wren-generate-mdl