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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the workflow role of this call (id discovery prerequisite), which is useful context beyond the annotations, but it says nothing about ordering, size, or refresh behavior of the returned source list.

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 sentences, no filler, with the purpose stated first and the prerequisite guidance second. Every clause carries information an agent needs before calling.

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 zero-param, read-only discovery tool with an output schema present and annotations covering the safety profile, the description only needs to state purpose and sequencing. Both are present, including the alternative URI access path.

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 tool takes zero parameters, so there is no parameter semantics for the description to elaborate and the baseline applies. The schema already sets additionalProperties=false, so nothing further is needed here.

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 opens with a specific verb+resource: "List the configured Learnosity documentation sources." That clearly distinguishes it from read_document or search_docs_sources, which consume source ids rather than enumerate them. It does not explicitly contrast with the close sibling list_docs_categories, keeping it short of 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?

It states the usage context directly: call this "before searching or reading" to discover valid source ids, and it names an alternative (learnosity://sources/index) for the same purpose. It does not say when not to use it or how it relates to list_docs_categories, so a small gap remains.

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