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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety bar is low. The description still adds meaningful context beyond them: results are limited to 'visible' stores and countryCodes (permission-scoped visibility), and the HGRApi header/channel is resolved internally so the caller need not supply it.

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, front-loaded with the core action and scope, followed by the optional filter and auth prerequisite. No redundant or filler text.

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 two-parameter read tool with a fully documented schema and an output schema that covers return values, the description supplies enough to call it correctly, including the auth prerequisite and visibility scoping. The only real omission is disambiguation from the other hgr_get_sources* variants.

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 both parameters are already documented in the schema with an example country list and the channelOAuthId provenance. The description restates rather than extends this, adding no format or edge-case detail beyond what the schema gives.

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 ('Lists current sources/suppliers from WAPI') plus its scope ('for one visible store/channel'), so the operation is unambiguous. It does not, however, distinguish itself from closely named siblings such as hgr_get_sources_get, hgr_get_sources_getpublic, hgr_get_sources_goout, or hgr_get_source_configuration, which an agent must guess between.

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?

Implies usage by naming the prerequisite 'channelOAuthId returned by hgr_list_channels' and by noting countryCode is an optional filter, which gives a usable call sequence. It never says when to pick this over the near-identical hgr_get_sources_* siblings, and offers no exclusions or conditions.

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