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

Goes well beyond the readOnlyHint/openWorldHint annotations: it explains that published_at is always null, that modified_at is the page edit date rather than the story date, that the page may cover a broader topic, that redirects are tracked via requested_url/final_url, and that a not-found error is permanent with three named causes.

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?

Purpose is front-loaded in the first clause, followed by input contract and then edge-case semantics. Every sentence carries distinct, load-bearing information with no repetition of schema or annotation content.

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, yet the description still frames what is returned, and it fully covers the input contract, redirect behavior, date-field caveats, and error semantics. Nothing an agent needs to invoke this 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 coverage is 100% for the single url param, so the schema already documents the two acceptable URL forms. The description reinforces this and adds redirect-tracking context (requested_url/final_url), modestly exceeding the baseline for a fully-covered schema.

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?

Opening sentence states a specific verb (Fetch), a specific resource (one page from BBB's evergreen /all/ library), and enumerates the returned fields. It also implicitly distinguishes itself from bbb_article by noting BBB folds older stories into these pages.

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 tells the agent what to pass (page URL, or an article URL that bbb_article reported as moved) and routes the not-found case back to bbb_article when the article was not actually moved. Conditions for each path are named rather than left to inference.

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