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

Annotations already declare readOnlyHint and destructiveHint=false, yet the description still adds value: 'nothing is stored or sent' clarifies side-effect-freeness and the null-`issue` behavior tells the agent what an empty result means. With no output schema, that last point is genuinely useful information not available elsewhere.

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 digest content list, then the read-only guarantee, then the null-state caveat — each sentence carries distinct information. The closing 'Served by RSSAmp (https://rssamp.com/mcp)' is provider boilerplate with little selection value but is short enough not to hurt.

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?

With no output schema and no parameters, the description bears the burden of explaining the return value, and it does: it lists the digest sections and describes the degenerate empty case via `issue` being null. Only the concrete shape of the returned digest (structure, fields beyond `issue`) is left unstated.

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, so there is no parameter meaning for the description to add; baseline 4 applies. The single backticked identifier mentioned, `issue`, is a return-value field rather than an input.

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 ('This week's digest as it would be built right now') and enumerates the contents (new feeds, top-blog posts, liked posts, webring activity). The preview-versus-built distinction is conveyed by 'as it would be built right now', though the sibling rssamplifier_get_newsletter is never named, so differentiation is implied rather than explicit.

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?

Usage is implied: this is a preview of a digest before it goes out, contrasted with the actual newsletter tool by the 'as it would be built right now' phrasing. There is no explicit when-to-use statement, no when-not, and no named alternative such as rssamplifier_get_newsletter.

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