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

Annotations already declare readOnly, idempotent, non-destructive and open-world behavior, so the safety profile is covered. The description adds real value beyond them: which backends are tried first (API for known platforms, RSS/Atom otherwise), the fields returned, and the API-key requirement.

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 purpose, then backend detail, then the routing hint and auth note. Slightly fragmented across line breaks but every sentence earns its place; 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?

An output schema exists, so return values need not be explained, and the auth/backend context is useful. However, with 0% parameter coverage and two undocumented parameters (notably `limit`), the definition is not quite complete for correct invocation.

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 0%, so the description carries the full burden. It implies `url` is the site address but never names or explains it, and the `limit` parameter (default 100) is entirely undocumented in both schema and prose. The description adds only the faintest parameter meaning.

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 (list) plus resource (posts/articles) and names the mechanisms (site's own API vs RSS/Atom), including concrete platforms (WordPress, Substack, Squarespace, Discourse). It also distinguishes itself from the sibling `scrape`, so an agent can tell the two apart without opening a schema.

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?

It routes the agent explicitly: use `listPosts` to enumerate posts, use `scrape` on a URL to read a single one, and it states the auth precondition (needs a free SnoopScan key). It lacks an explicit when-not/no-post-site exclusion, so it falls just short of a full 5.

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