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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds the useful behavioral claim that the slugs are 'verified' and 'accepted by' a specific sibling, but says nothing about cardinality, ordering, or caching of the returned list.

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?

One sentence, front-loaded with the resource, ending with the actionable next step. No filler or restatement of the tool name.

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, and the single behavioral fact an agent needs (these slugs are the valid inputs for expresstribune_headlines) is present. Only minor gaps remain, such as whether the list is exhaustive across all sections or refreshed periodically.

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?

The tool takes zero parameters and the schema is a closed empty object, so there is nothing for the description to disambiguate; the baseline for a parameterless tool 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?

Specific verb ('List') plus a precisely scoped resource ('every verified Express Tribune RSS section slug'), and it names the consumer of those slugs (expresstribune_headlines), which cleanly separates it from the article/author/news 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?

The clause 'choose a section from this result' explicitly tells the agent this is an enumeration step feeding expresstribune_headlines, implying when to call it. It stops short of stating the inverse (don't call headlines with an unverified slug) or naming exclusions, so it is clear context rather than a full when/when-not rule set.

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