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 without the description. What it adds is scoped content behavior — that the body comes back as plain text and that the content is educational rather than advisory — but it says nothing about error handling for an unknown slug or payload size.

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 short sentences with the primary action front-loaded and no filler. The field enumeration duplicates what the existing output schema already declares, making it the only wordy element.

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 one fully documented parameter, rich annotations, and an output schema covering return values, the definition needs little more than it provides. Only the failure mode for a missing/invalid slug and any truncation of the body text remain unaddressed, which are minor gaps for this complexity level.

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 100% and the single slug parameter is documented in the schema, including an example value and the list_guides provenance. The description adds only a restatement ('by slug'), which is the expected baseline when the schema already carries parameter semantics.

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?

The description states a specific verb and resource ('Get one guide by slug') and enumerates the returned fields, so it is clearly distinguishable from list_guides or search_content. It stops short of explicitly routing to those siblings, which keeps it just under a 5.

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 only implied: fetching a single guide by slug is obviously the terminal step after a listing call, and the schema note points at list_guides for slug discovery. The description itself contains no explicit when-to-use or when-not-to-use guidance, and 'Education only, not financial advice' is a content disclaimer rather than invocation guidance.

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