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

Annotations already indicate readOnly, idempotent, and non-destructive behavior. The description adds the output format (ZIP archive), which is useful context. It does not contradict the annotations and covers the primary behavioral detail.

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?

The description is two sentences with no fluff. It states the purpose and the key constraint (custom-only) efficiently, making it easy to parse.

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 download operation with a single parameter, the description is complete. It specifies the output format and the condition (custom-only), which is sufficient for an agent to decide and invoke correctly without further details.

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 provides format and pattern for skill_id. The description's mention of 'custom skill' clarifies that skill_id should reference a custom (team-owned) skill, adding meaning beyond the bare 'Skill ID.' schema description.

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 action (download), the resource (custom skill), and the output format (ZIP archive). It also distinguishes from listSkills and getSkillFileContent by specifying the ZIP archive format and the custom-skill restriction.

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?

The description explicitly states a when-not condition: only custom (team-owned) skills can be downloaded. It implies when to use this tool (when a ZIP archive of a custom skill is needed) but does not explicitly mention alternative tools like getSkillFileContent for system skills, hence a slight deduction.

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