A reference for DataCanvas, a DuckDB-backed workspace for registering tables, querying them with SQL, and exporting results. DuckDB is a database designed to analyze local or in-process data; SQL is a language for filtering, joining, and summarizing tables.

Use it to load API results into tables, run ad-hoc reports or joins, apply table expiration times, and export data as CSV, Parquet, or JSON. It is intended for analytical data, not simple search or metadata lookup.

It provides a documented way to analyze tabular data from several APIs instead of passing large or awkward datasets through separate tool calls. It also explains when the optional feature should be enabled and where it is unsupported.

api-canvas — Skill for Claude Code by cyanheads/cdc-health-mcp-server

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 cyanheads/cdc-health-mcp-server --skill api-canvas

Clone the repo

git clone --depth 1 https://github.com/cyanheads/cdc-health-mcp-server

Made for: Claude Code.

Or install cdc-health-mcp-server, the plugin that ships this one along with the rest of its 35 skills, 1 MCP server.

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/cyanheads/cdc-health-mcp-server/api-canvas/github.svg)](https://agentmods.dev/skills/cyanheads/cdc-health-mcp-server/api-canvas)

Your own site

<a href="https://agentmods.dev/skills/cyanheads/cdc-health-mcp-server/api-canvas"><img src="https://agentmods.dev/badge/skills/cyanheads/cdc-health-mcp-server/api-canvas/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/cyanheads/cdc-health-mcp-server/api-canvas"><img src="https://agentmods.dev/badge/skills/cyanheads/cdc-health-mcp-server/api-canvas.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 85 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 10,564 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin 100% copy Near-identical to another mod 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	$0.00085	$0.10564
Opus 5.5	$0.00034	$0.04226
Sonnet 5.5	$0.00017	$0.02113
Haiku 4.5	$0.00009	$0.01056

Measured 6d ago against content hash 9215b0c142a6, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

api-canvas 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 6d 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.

Origin

This is a copy

100% identical to api-canvas — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

framework-skills/api-canvas/SKILL.md · 594 lines

How it starts

The opening of the file, as written. The whole thing — 594 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Overview

DataCanvas is a primitive for storage stashes, canvas computes. The existing IStorageProvider is a key/value abstraction — it can stash blobs but exposes no analytical surface. DataCanvas is the analytical surface: register tabular data from upstream APIs, run SQL across multiple registered tables, and export results as CSV/Parquet/JSON.

Tier 3 — @duckdb/node-api is an optional peer dependency (bun add @duckdb/node-api; 1.5.5-r.1 and later 1.5.x, or 2.0.0-r.1 and later 2.x). Servers that don't enable canvas pay zero install cost. Lazy-loaded on first use.

Disabled by default. Set CANVAS_PROVIDER_TYPE=duckdb to enable. Otherwise core.canvas is undefined.

Cloudflare Workers: unsupported. DuckDB has no V8-isolate build. Setting CANVAS_PROVIDER_TYPE=duckdb on a Worker fails closed with a ConfigurationError at init time.

When canvas earns its keep

Two gates before wiring canvas in — both must be yes. Canvas that fails either is a SQL surface nobody queries.

Is the data analytical, not just large? Canvas is for tabular/numeric result sets an agent runs SQL over — aggregate, group, join, time-series filter. A discovery/search surface returning categorical metadata (titles, IDs, types, dates) where the workflow is find the record, then drill into it does not qualify, regardless of row count. A 5,000-row search result is still discovery. The gate is shape, not size: the right question is "would an agent write SELECT … GROUP BY against this?", not "does it have many rows?" For name→ID resolution over a bounded list, reach for MCP-side list filtering (see the design-mcp-server skill) instead.
Is it too big to inline? A result that fits the response (≤ ~100 rows of compact data) just gets inlined — no canvas. Canvas is the third option only when shape and size both call for it.

If canvas earns its keep, it carries an obligation: a tool that emits a canvas_id MUST ship a dataframe_query tool in the same server's surface (see the simple-shape Tools row and the Checklist). A canvas_id with no query tool is dead output — the agent literally cannot reach the staged data.

Read the full file on GitHub · 594 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.

6d ago Changed · +1 lines 9215b0c142a6
26d ago Changed · +7 lines ccd12b0799e3
1mo ago Changed · +9 lines 21b3b7bd133a
1mo ago Changed · +21 lines b7ea375ffd05
2mo ago First seen · 556 lines · 85 tokens per session scan A a15da8c76763

Subscribe to this mod's changes

api-canvas is a skill published in the GitHub repository cyanheads/cdc-health-mcp-server (5 stars, last pushed 7d ago), licensed Apache-2.0. It adds 85 tokens to every session and 10,564 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to api-canvas, differing in 0 lines, and is treated as a copy.

Analytics and metrics Databases cdc health-data mcp mcp-server model-context-protocol public-health

api-canvas next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
api-canvascyanheads/cdc-health-mcp-server	Skill	5	7d ago	Apache-2.0	A	85	Claude Code
ssh-managerbvisible/mcp-ssh-manager	Skill	534	3d ago	MIT	A	79	Claude Code, Codex
servicenow-cmdbjschuller/mcp-server-servicenow	Skill	27	3d ago	MIT	A	110	Claude Code
build-sql-transformationkeboola/mcp-server	Skill	85	yesterday	MIT	A	54	Cursor
exploring-tablesjschuller/mcp-server-servicenow	Skill	27	3d ago	MIT	A	134	Claude Code
explore-project-datakeboola/mcp-server	Skill	85	yesterday	MIT	A	49	Cursor
datagateServosity/msp-skills	Skill	72	yesterday	none	A	65	Claude Code