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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, covering safety and idempotency. Description adds that the output is SVG markup, but does not discuss error handling (e.g., unknown icon) or rate limits. With annotations present, the description adds modest value.

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?

Two sentences: first conveys purpose with verb and resource, second gives concrete usage guidance. No extraneous words, well-structured and front-loaded.

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?

For a simple read-only icon retrieval tool with full schema coverage and annotations, the description suffices. It tells the agent exactly what the tool does, how to get parameters, and what it returns (SVG markup). No gaps given the low complexity.

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 has 100% coverage with descriptions for all 4 parameters. Description adds critical context by linking collection and name to search_icons results and providing an example, helping the agent understand how to populate parameters correctly.

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 states the tool retrieves SVG markup for a specific icon, with verb 'Get' and resource 'SVG markup'. It distinguishes from siblings like get_collection_icons (multiple icons) and search_icons (searching) by linking to search_icons results. The example clarifies usage.

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?

Description explicitly advises to use collection and name from a search_icons result, providing clear context for when to invoke this tool. It does not formally exclude siblings but the purpose differences are implicit from their names and this description.

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