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

Annotations already cover safety (readOnlyHint) and reach (openWorldHint), so the bar is lower. The description adds genuinely useful behavioral context beyond them: the payload is limited to 'public metadata and body paragraphs', and paywalled/blocked URLs surface as an upstream error rather than partial data.

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, no waste, front-loaded with the core action and immediately followed by the sibling routing and the error caveat. Every clause 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?

An output schema exists, so return values need not be described. The description covers the action, discovery path, input format, and failure mode, which is everything an agent needs to call a single-URL fetch tool correctly.

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 coverage is 100% with a single required 'url' property, so the baseline is 3. The description adds a constraint beyond the schema: the URL must be a canonical HTTPS article URL, which clarifies the accepted format rather than just restating the field.

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 verb (Fetch), the resource (one canonical HTTPS Business Insider article URL), and the payload scope (public metadata and body paragraphs). An agent can immediately distinguish it from businessinsider_headlines and the other Business Insider siblings.

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?

Explicitly routes the agent: use businessinsider_headlines to discover article links, then call this to fetch one. It also names the failure condition (subscriber-only or blocked articles return an upstream error), so the agent knows when this tool will not succeed.

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