Tanod MCP server

utilpeek: make a 1-D barcode image (SVG or PNG)

make_barcode

Idempotent

Generate 1-D barcode images (Code128, EAN-13, EAN-8, UPC-A, ISBN-13, Code39) as SVG or PNG; validate checksums and return base64 or a 24-hour URL.

Instructions

utilpeek: make a 1-D barcode image. For QR codes use make_qr_code. Returns svg (text, with width_mm/height_mm) or data_base64 (PNG, with width_px/height_px; output "url": a 24 h link), plus encoded and bytes. A supplied check digit (ean13, ean8, upca, isbn13) must be right: a wrong one is a 422 invalid_checksum (not charged) rather than silently encoding a different number. Encoded locally; typically under 0.1 s. Price: USD 0.001. Free: 10 utilpeek calls per IP per UTC day. Docs: https://tanod.dev/learn/barcode-generator-api.html

Input Schema

TableJSON Schema

Name	Required	Description	Default
`data`	Yes	Value to encode (see the type rules).
`text`	No	Print the human-readable line (default true).
`type`	No	Symbology (default code128).	code128
`format`	No	svg (text) or png (base64).	svg
`output`	No	base64 (default): the file comes back inline as base64. url: the file is stored for 24 hours and the reply carries a download link (url, expires_at, bytes, content_type, sha256) instead of the base64, which keeps the file out of your context window.	base64

Output Schema

TableJSON Schema

Name	Required	Description
`svg`	No
`text`	No
`type`	No
`bytes`	No
`error`	No	Only on an error result: an object {code, message}, or the reason string of an x402 PaymentRequired object.
`format`	No
`source`	No
`encoded`	No
`width_mm`	No
`width_px`	No
`height_mm`	No
`height_px`	No
`data_base64`	No
`content_type`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.0Oct 15, 2026

TDQS

A4.6/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond annotations, the description discloses important behavior: wrong check digits produce a 422 invalid_checksum without charge, encoding is local and typically under 0.1s, pricing is USD 0.001, and the free tier is 10 calls per IP per UTC day. These details materially affect how an agent should invoke and retry the tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with purpose and the QR-code alternative before moving through return values, validation behavior, performance, price, quota, and docs. Every sentence carries operational value for an agent deciding whether and how to call the tool.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With a rich output schema and 100% parameter schema coverage, the description is largely complete and even redundantly explains return values. The main remaining gap is symbology-specific data rules beyond check digits, though the docs link and schema enums partially mitigate that.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3 even without extra parameter detail. The description adds meaningful constraint semantics: for ean13, ean8, upca, and isbn13, a supplied check digit must be correct or the request fails with 422 rather than silently encoding a different number.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: make a 1-D barcode image. It explicitly distinguishes itself from the QR-code sibling by naming make_qr_code. An agent can identify the tool's core function immediately.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives an explicit alternative for QR codes: use make_qr_code. That is useful routing guidance, but it does not cover other selection contexts, such as when to choose PNG vs SVG or URL vs base64 beyond what the schema already documents.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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