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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered by structured data. The description adds almost nothing behavioral beyond the word "summary" – it does not say what the summary omits relative to the full guide, nor what happens when the slug is unknown (empty result vs. error).

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?

Six words with zero padding and the key qualifier ("by slug") front-loaded. Brevity is not the problem; being underspecified rather than efficient is why it lands at the middle of the scale.

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 low-complexity single-parameter read tool with annotations and no output schema, the bar is modest, but the description still leaves the slug format and the notion of "summary" undefined. An agent can guess how to call it, but not confidently what it will receive.

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 single parameter has 0% schema description coverage, so the description carries the full burden, and "by slug" only tells the agent that the value identifies a guide. It gives no format, source (where slugs come from), or case/URL-safety expectations.

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?

"One guide summary by slug" implies a single-resource fetch keyed by slug and the word "summary" hints at a reduced representation. It does not use a verb and never explicitly contrasts with search_guides or get_data_study, so the agent must infer that this is the direct-lookup sibling of the search tool.

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?

"By slug" implies you need a slug, but there is no statement of when to use this versus search_guides, nor what to do if you only have a name or ID. No prerequisites, no fallback guidance.

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