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 real behavioral detail: 20 items per page, newest-first ordering, inclusion of total pages/results, and that resolved_topic can differ from the requested topic for edition-scoped fronts. That is useful non-obvious context beyond annotations.

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?

Front-loaded with the core return behavior and packed with specifics; every clause carries information (paging, ordering, front flag, resolved_topic). Slightly dense but no filler.

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?

For a 2-param read-only listing tool with an output schema present, the description covers purpose, paging, ordering, the dual-mode distinction, and the sibling alternative. Return values needn't be spelled out given the output schema, so remaining gaps are minor.

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%, so the baseline is 3, but the description adds meaning: topic accepts either a tag or a section slug, which selects the archive-vs-front behavior, and page defaults to 1. This clarifies the semantic role of the topic param beyond the schema's bare 'Guardian tag or section slug'.

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 and resource: returns stories for a Guardian tag archive OR a section front, with the two modes distinguished (20-per-page archive vs single curated front with is_front true). It also names the sibling guardian_article and clarifies the boundary. Clear, though the dual-mode scope takes reading.

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?

Gives explicit context (browsing a tag or section) and routes the agent to guardian_article for article content. It doesn't state when-not or list other news siblings, but the alternative for full article retrieval is named.

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