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

Adds one behavioral cue beyond the schema: 'Title discarded after the call' tells the agent the title is not retained. However, there are no annotations to carry the safety/read-only burden, and the description does not disclose how the check is performed, whether any state changes occur, or what the result contains.

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 with no filler, and the core operation is front-loaded. The second sentence earns its place by adding a behavioral note about data disposal.

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 seven parameters, no annotations, and no output schema, this definition is far too thin to support correct invocation. There is no way to know which parameter supplies the Wikipedia title, what 'exists' returns, or how this tool relates to sibling validators.

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 descriptions cover all seven parameters, so the baseline is 3, but the description introduces a 'title' concept that has no corresponding property in the schema (ref, url, city, feed, host, json, path). This actively confuses parameter mapping instead of adding useful meaning beyond the schema.

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?

States a specific intended operation: check whether a Wikipedia title exists, with a clear verb and resource. It does not differentiate itself from sibling validation tools, and the schema exposes no title parameter, which makes the purpose harder to act on, but the descriptive intent itself is clear.

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?

Provides no guidance on when to use this tool versus alternatives such as domain-shape, validate-json, or normalize-url. There are no when/when-not conditions or named alternatives, so the agent must infer selection purely from the tool name and one-line description.

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