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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds useful behavioral context by enumerating what is fetched (byline metadata, bio, social links, recent article items). It stops short of mentioning pagination or freshness of the "recent" items, keeping it from a 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?

Two sentences, zero waste: the first front-loads purpose and output content, the second handles routing. Nothing is redundant and the most important information leads.

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 explained, and annotations cover the safety profile. Purpose, targeted content, and alternative routing are all present, leaving nothing an agent needs to call this correctly 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?

Schema description coverage is 100% for the single `url` parameter, so the schema already documents it as a canonical NBC News author URL. The description only echoes "canonical author `url`" and adds no format or syntax detail beyond what the schema provides — the baseline 3 for high coverage.

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?

Specific verb ("Fetch") plus resource ("NBC News author's byline metadata, bio, social links, and recent article items") with the input anchor ("canonical author `url`"). It explicitly distinguishes itself from nbc_article, nbc_headlines, and nbc_sections, so an agent can identify it among the huge sibling set 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?

Second sentence routes the agent precisely: nbc_article for one story, nbc_headlines for section stories, nbc_sections to browse sections. It names the alternatives and the conditions that select them, which is exactly the when-vs-alternatives guidance this dimension wants.

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