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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds value beyond that by disclosing the shape of the result — each entry carries a license and refresh cadence — which matters because there is no output schema to reveal those fields.

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 tight sentence with the resource first and the returned fields second; no filler, no restatement of the title. Every clause earns its place.

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 simple read-only, no-argument enumeration tool with no output schema, the description gives enough: what is listed, what attributes come back, and the domain of the data. Ordering, completeness guarantees, or how often refresh values change are not addressed, but nothing required for a correct call is missing.

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 nothing for the description to disambiguate; the baseline for a parameterless tool applies. The schema is fully specified and the description correctly makes no parameter claims that could conflict.

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?

Names a concrete verb ("List") and resource ("sources") and clarifies what a source is in this domain: where the alarm company data comes from, including per-source license and refresh metadata. That is specific enough to separate it from catalogue-style siblings like list_courses or list_products, though it never explicitly contrasts itself with any of them.

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?

Usage is only implied: there are no parameters, so the tool is unambiguously 'list everything', but the description never states when to call it or what to do instead if the agent wants a single source. For a trivial zero-argument lister this implied guidance is acceptable but leaves a gap.

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