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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), so the bar is lower. The description adds genuinely useful behavior: premium stories return only an anonymous one-paragraph teaser with `paywalled` set to true, which tells the agent to expect truncated content. It stops short of describing pagination or other edge behavior, so not 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?

Three short sentences with zero waste; the core fetch behavior and paywall caveat are front-loaded, and the sibling routing comes last. Every sentence 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 no explanation, yet the description still supplies the crucial paywall/teaser behavior. For a single-parameter fetch tool, nothing an agent needs to call it correctly is 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% and the single `url` parameter is already documented as the canonical article URL. The description echoes 'canonical url' but adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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), a concrete resource (Irish Independent article metadata and body paragraphs), and scope (public, canonical url). It clearly distinguishes itself from the sibling headlines/news tools by naming what it returns versus what they return.

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 irishindependent_headlines to find stories or irishindependent_news for the general feed, implying this tool is for fetching a specific already-known article. The alternative selection condition is stated rather than inferred.

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