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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description's only behavioral addition is the implicit prerequisite that the story must be 'followed', and it otherwise restates return content that the output schema already carries.

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?

Two compact sentences: the retrieval scope and returned fields come first, the intended use case second. Every clause is load-bearing, though the trailing 'plus the location' is slightly vague about whose location is returned.

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 structure need not be explained, and annotations cover the safety profile; the description still supplies the missing provenance and purpose. It does not mention pagination or limits on long timelines, a minor gap for a historical-list tool.

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?

With only one parameter and 100% schema coverage, the baseline is 3, but the description adds real value by naming three concrete sibling tools that produce a valid slug, whereas the schema only cites a raw endpoint and a URL path. That provenance guidance is meaningfully beyond the schema text.

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 — retrieving the full timeline of a followed story by slug — and enumerates the returned content (stages in order with label, time, summary, per-portal report, location). Naming the sibling sources for the slug (list_stories, get_article, research_topic) makes it clearly distinguishable from the article- and search-oriented 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?

Gives explicit usage context ('Use to explain how a story developed') and states where the slug comes from, which is the main prerequisite for calling it. It stops short of saying when NOT to use it (e.g. a single-article read is get_article), so it is clear but not fully exclusive.

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