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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description still adds real context: these are skills that each 'render an MP4 on the user's machine', telling the agent the listing itself is local and non-rendering and that results are video generators. It does not mention pagination or result ordering.

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 short sentences, front-loaded with the verb and resource, with the parenthetical and second sentence both doing useful work. Nothing is redundant or 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?

For a one-optional-parameter, read-only listing tool with no output schema, this is close to complete and does not need to describe return values. The one gap for chaining purposes is that it never hints at what identifying fields a listed skill exposes (needed to feed get_skill or get_install_command).

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 description coverage is 100% and the single optional `free` flag is fully documented in the schema ('true for free skills only, false for Pro only'), so the schema carries the load. The description adds nothing about the free/Pro filter or the default behavior when the flag is omitted, so baseline 3 applies.

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?

"List every Lookbk video skill" gives a specific verb plus resource, and the parenthetical enumerates the concrete skill categories so an agent knows what a 'video skill' is. It implicitly contrasts with search_skills by saying 'every', but never names the sibling or states the enumeration-vs-search boundary explicitly.

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?

Usage is only implied: 'every' suggests a full unfiltered enumeration, which is the natural alternative to search_skills, but the description never says when to pick this over search_skills or get_skill. No prerequisites or exclusions are stated.

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