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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: it validates retail check digits and lengths (i.e. it can fail on bad input) and documents the bracketed GS1 application-identifier input syntax.

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

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

Three tight sentences: output form first, then validation behavior, then input syntax, then the alternative tool. Every sentence carries distinct information with no repetition of the schema.

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

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

With no output schema, the description correctly names the return artifact (SVG), and it covers validation failures and GS1 syntax for a two-parameter tool. Minor gaps remain: no mention of symbol sizing/options or what a validation failure looks like in the response.

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

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

Schema coverage is only 50% (format has no description), so the description compensates by explaining the GS1-128/DataMatrix bracketed input form such as (01)GTIN(17)YYMMDD(10)lot and the per-format validation rules that constrain `text`. The 1024-byte limit is left to the schema, which already states it.

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

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

States a specific verb and resource ("Make an SVG barcode") plus the formats it supports, and explicitly separates itself from make_qr. An agent can distinguish it from read_barcode and make_qr without opening either schema.

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

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

Explicitly routes QR requests to make_qr, which is the main sibling ambiguity in this space. It does not, however, say when to pick each barcode format (e.g. ean13 vs code128 vs datamatrix), so format selection is left to the enum.

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