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

Annotations already declare this a safe, non-destructive, closed-world read, so the safety burden is covered. The description adds real behavioral value by disclosing the payload an agent can expect (type, intro text, page count, main pages), which is meaningful because there is no output schema. It does not discuss paging, cost, or freshness, but the core disclosure is solid.

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, front-loaded with what is returned and closed with the usage cue. No filler or redundancy. It could be marginally tighter, but every clause carries information.

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 zero-parameter summary tool with annotations covering the safety profile and no output schema, the description supplies what an agent needs: the target site, the returned contents, and the when-to-use cue. Only the absence of sibling routing keeps it from being fully complete.

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 the baseline is 4. The description correctly implies a no-argument, whole-site call and introduces no parameter terminology that could confuse the agent.

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?

Names a concrete resource (the site instant.aigakushu.online) and enumerates what is returned: site type, description text, number of pages loaded, and main pages. This is more than a restatement of the name. It does not explicitly contrast itself with siblings like list_pages or get_page, which would be needed for a 5.

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?

Clearly states the trigger condition: 'use when you first want to grasp the overall picture of the site.' That gives the agent a concrete moment to reach for it. However, it names no alternatives or exclusions (e.g. when to prefer list_pages or search_pages instead), so it stops short of full routing guidance.

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