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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description usefully enumerates the payload (description, programme details, provider, price, duration, delivery type, languages), but says nothing about failure behavior for an invalid/unknown slug or how locale affects the response.

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 tight sentences, zero waste, with the core action front-loaded and the usage cue second. Nothing needs trimming.

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 compensates by listing the returned fields, which is the right move. It is nearly complete for a simple two-param read tool, missing only error behavior and the role of the locale parameter in the returned link.

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%, with both slug and locale fully documented including the locale default and allowed values, so the schema carries the burden and the baseline of 3 applies. The description adds no format or constraint detail beyond the schema; 'exactly as returned by the search tool' is already in the slug description.

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+resource: 'Fetch the full details of a single Hosco course by its slug.' It is clearly distinct from search-courses-tool, though it never names that sibling explicitly; the differentiation comes from 'single course by its slug' vs. a search.

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?

'Use this after a search result' gives clear sequencing context for when to invoke it. It stops short of naming the alternative tool or stating when not to use it (e.g. for multiple courses, use search-courses-tool).

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