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 needs no restating. The description adds genuine value by disclosing the returned fields and the content nature ('Education only, not financial advice'), but says nothing about failure behavior for unknown slugs or body length.

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 zero waste; the lookup key and return shape come first and the content caveat follows. Nothing is padded or repeated.

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, the description steps in and names the six returned fields, which is the key gap it needed to fill for a single-record fetch. What remains thin is edge behavior (missing slug, truncated body) for a tool whose annotations already cover the safety profile.

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% and the single slug parameter is documented with an example value plus its source tool, so the schema carries the burden. The description only restates that lookup is by slug, adding no format or validation detail beyond what is already structured.

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 ('Get one guide by slug') and enumerates exactly what comes back (title, description, publishedAt, readingTime, url, plain-text body). The singular 'one guide' implicitly contrasts with the sibling list_guides, but that sibling is never named, so the differentiation is inferred rather than stated.

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?

There is no explicit when-to-use or when-not-to-use guidance in the description itself; the usage condition is only implied, and the retrieval workflow is documented in the schema's slug property ('Guide slug from list_guides'), which points the agent at the right prerequisite. Adequate but relying on the schema rather than the description to route the agent.

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