ls_list_files

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

The annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the safety profile is known. The description adds valuable behavioral details: pagination via `meta.page` and the cross-store requirement for `variantId`, plus the API key boundary note. This goes beyond the annotations without contradicting them.

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 front-loaded with the core purpose and remains short, but has some awkward phrasing (e.g., 'at least one of: variantId' and a mid-sentence capital 'Pair'). Overall, it is appropriately sized and readable, earning a 4 rather than a perfect 5.

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 list tool with no output schema, the description covers the essential behavior: listing, optional filtering, pagination, and cross-store constraints. It does not explain the `include` parameter, but the schema already describes it, so this is sufficient for the tool's complexity.

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?

All parameters are documented in the schema (100% coverage), so baseline is 3. The description adds meaningful context by emphasizing the optional variant filter and the conditional requirement for `variantId` in cross-store scenarios, enhancing parameter understanding beyond the schema descriptions.

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 clearly states the verb ('List') and resource ('files'), with an optional filter by variant. This distinguishes it from the singular `ls_get_file` and other list tools by indicating the list operation and pagination behavior.

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 provides clear context for when to use this tool (listing files) and includes a specific conditional note about requiring `variantId` when `LEMONSQUEEZY_ALLOWED_STORE_IDS` is set. It does not explicitly mention alternatives, but the distinction from `ls_get_file` is implicit, and the cross-store guidance adds practical usage context.

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