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

Annotations already cover safety (readOnlyHint, idempotentHint, openWorldHint=false), so the bar is lower. The description adds real context beyond that: the filter is optional, an empty query lists everything, and the exact return fields are enumerated. It does not mention pagination or result limits, which is the remaining gap.

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?

Three sentences, front-loaded with the catalog identity and behavior, then routing, then return shape. The descriptor 'plain-language explainers with a diagram per concept' is mild marketing but does help disambiguate from the blog-post siblings.

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?

No output schema exists, and the description compensates by listing the returned fields (slug, title, summary, level, reading time, URL). Combined with the filter and language semantics, an agent has everything needed to call this correctly.

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%, so baseline is 3. The description adds genuine meaning by stating the query matches words 'in the title and summary' — which fields are searched is not derivable from the schema's 'Words to look for'. The language parameter's effect is left to the schema.

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 (list courses) scoped to a named catalog, and immediately distinguishes itself from get_course for full text. An agent can tell this apart from get_post/search_posts without opening any 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?

Explicitly names the sibling alternative and the condition that selects it: 'use get_course for the full text.' Filtering is framed as optional ('Optionally filter by words in the title and summary'), which sets the default behavior. No explicit when-not beyond the get_course boundary.

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