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

Annotations already carry readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely extra context: what the response contains (source, one-line description, page URL when present) and a behavioral constraint against proactive invocation. It doesn't cover the empty/zero-starred case, which keeps it below 5.

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 trigger condition is front-loaded and every clause carries information: trigger, example, return contents, prohibition. The middle clause is a slightly dense run-on bundling three returned fields, but it earns its place.

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 parameters and no output schema, the description must carry the return shape and invocation policy — and it does both. Nothing an agent needs to call this correctly 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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. Correctly, no space is wasted restating parameter information that does not exist.

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 gives a specific verb and resource ('lists them') and enumerates the returned fields (source, one-line description, getedge.cc page), which clearly separates it from sibling star_skill (a write) and find_skill/find_tool (searches). An agent can tell exactly what this returns without opening a 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?

It states the explicit trigger ('only when the user asks to see their starred, favourite or saved skills'), gives a concrete example utterance, and adds a hard exclusion ('Never call it on your own initiative'). Both when-to-use and when-not are covered with no inference required.

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