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

Beyond the annotations (readOnly, idempotent, non-destructive), the description adds valuable behavioral detail: no auth required, error behavior for malformed or unknown ids, and a size-based fallback where svg_url is returned instead of inline markup. It also notes attribution requirements, giving a fuller operational picture.

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?

Every sentence carries functional weight: primary purpose, usage routing, behavioral caveats, and attribution. The most important information is front-loaded, and the description is dense without being padded.

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 a single required parameter and no output schema, the description provides everything needed to call the tool correctly: id format, id source, return type, error behavior, fallback condition, and alternative tools. Nothing essential is missing.

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?

The schema already documents the parameter at 100% coverage, but the description adds practical meaning with a concrete id format example ('hammer-16_66091') and directs the agent to search_icons for valid ids. This goes beyond the schema text.

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?

The description clearly identifies the action (return SVG markup), the resource (ONE Infyicon icon by id), and the exact usage context. It explicitly distinguishes itself from siblings like get_icon_svg_bulk and get_icon_png, so an agent can select it without ambiguity.

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?

It provides explicit when-to-use guidance ('Use when the user wants inline SVG for a single icon') and names alternatives with their conditions ('use get_icon_svg_bulk for 2-20 icons... use get_icon_png when they need a raster image URL'). It also tells the agent where to obtain valid ids, via search_icons.

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