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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds that the output includes 'normalized source snapshots,' which hints at the response content but does not describe pagination, ordering, or other behavioral details. This is adequate but not rich, given the annotations.

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?

The description is a single, concise sentence that starts with the action verb 'List' and immediately states the resource. There is no redundant wording, and every phrase contributes meaning.

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, parameterless list operation with strong annotations, the description is mostly complete. It states what is listed and hints at the output type, but without an output schema, some ambiguity remains about the exact structure of 'normalized source snapshots.' Still, for this level of complexity, it is sufficient.

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 input schema has zero parameters, so the schema itself provides full coverage (100%). The description does not need to explain parameter semantics, and the baseline for zero parameters is 4.

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 uses the specific verb 'List' followed by a clear resource: 'local public-safe external supply sources and normalized source snapshots.' This states the tool's domain and scope, and it is distinct from sibling tools like 'search_external_marketplaces' and 'inspect_external_supply_candidate.' However, it does not explicitly call out those alternatives or their relationship, so it falls 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?

The description implies the tool is for retrieving a specific subset of external supply sources (local public-safe) and normalized snapshots, but it gives no explicit guidance on when to prefer this over searching or inspecting other marketplaces. There is no mention of exclusions or alternative approaches, making the usage context clear only by inference.

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