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

Adds rich behavioral context beyond the readOnly/openWorld annotations: an edge challenge can force browser rendering at 10 credits vs 2, and it explicitly clarifies this does not bypass authentication or access controls. Cost and rendering behavior are exactly what annotations cannot convey.

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: purpose first, then the cost/rendering caveat, then sibling routing. Nothing is redundant and the most decision-relevant information is front-loaded.

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 an output schema present, the description needn't describe return values, and it covers purpose, cost behavior, auth boundaries, and alternatives. An agent has everything needed to invoke it 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 'url' parameter already documented as the canonical AP News article URL. The description restates 'canonical url' without adding format or syntax detail, so baseline 3 is appropriate.

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') and resource ('public AP News article metadata and body paragraphs') scoped to a canonical url. It explicitly names sibling tools (apnews_headlines, apnews_fact_check) so the agent can distinguish this from discovery/fact-check tools.

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?

Names two alternatives with their purposes, routing the agent toward apnews_headlines for discovery and apnews_fact_check for fact-check coverage. It implies but does not literally state the selecting condition (you already hold the canonical article URL).

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