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

Annotations already declare this a safe, idempotent, closed-world read, so the description needn't restate safety. It does add value by disclosing what each returned source carries — a license and a refresh value — which partially substitutes for the missing output schema, though it says nothing about ordering, counts, or failure modes.

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?

A single sentence with the resource front-loaded and the returned fields attached directly to it. No redundant restatement of the name or the read-only nature.

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 parameterless list tool with no output schema, the description covers what is listed and two of the fields returned, which is close to sufficient. A bit more on the shape of the result (e.g., roughly how many sources or their granularity) would make it fully complete.

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 no parameters, so there is nothing for the description to disambiguate. Baseline 4 applies for a parameterless tool whose schema is fully covered.

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 gives a specific verb (List) and resource (sources) and clarifies what a 'source' means in this domain — the origin of the electrician data — along with the per-source fields (license, refresh). That is enough to separate it from siblings like list_categories or list_products, though it does not explicitly name a contrast case.

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 statement, and no alternative is named. For a zero-parameter, read-only listing tool the intent is reasonably inferable from the content described, so the usage is implied rather than guided.

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