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

Goes beyond readOnlyHint/openWorldHint by disclosing a non-obvious trait: the metered overlay is client-side and anonymous requests still receive the full body "as served." This directly answers the agent's likely worry about hitting a paywall. It does not cover pagination or request limits, so it is strong but not exhaustive.

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?

Three tight sentences, front-loaded with purpose, then the paywall caveat, then sibling routing. No filler; each sentence carries distinct 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?

Single-param read tool with an output schema (so return values need no explanation) and annotations covering the safety profile. The description closes the remaining gaps: paywall behavior and how this differs from sibling list/feed tools.

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 parameter the schema already documents, so baseline is 3. The description's "canonical `url`" adds a minimal clue that the URL must be canonical, but no format guidance 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 verb+resource ("Fetch ... story metadata and body paragraphs") with scope ("public", "canonical url"), and names the sibling tools it is not (headlines/sections/news). An agent can route to it from a story URL without opening any other 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?

Explicitly names three sibling tools and the roles they serve (find stories, browse topics, general feed), which positions this as the detail-fetch tool. It stops short of stating the inverse condition ("use this once you have a URL from seattletimes_headlines"), so it is clear context rather than a full when/when-not rule.

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