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

Annotations already declare read-only, idempotent, non-destructive behavior. The description adds behavioral context not in annotations: the public-only scope, paging, sortable by 'views' or 'date', and the default 'latest' behavior when no ref/user_id is provided. This is useful and consistent with 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 compact bulleted list with the main verb and resource front-loaded. Each bullet adds a distinct mode without unnecessary prose, making it easy to scan and parse.

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 tool with five optional parameters and no output schema, this is workable but incomplete. The main modes are covered, but the description leaves interaction rules unspecified (e.g., whether ref and user_id can be combined, and whether paging/sort applies to all modes or only the user mode). An agent may need to make assumptions for edge combinations.

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?

With 0% schema description coverage, the description carries the burden for all five parameters. It gives real meaning for ref, user_id, and sort_by, and mentions 'with paging' for limit/offset, but it does not explicitly define how limit and offset behave across modes or clarify whether ref and user_id can be combined. This is partial compensation, not full.

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 uses the verb 'List' with the resource 'public source sheets' and enumerates three lookup modes (by passage, by user, latest), which is specific enough for an agent. It does not explicitly name or contrast sibling tools like get_source_sheet or browse_library, so it stops just short of full sibling differentiation.

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 three bullet modes give clear conditions for when to call the tool: pass ref for sheets using a text, pass user_id for a user's sheets, or pass neither for latest. It provides no exclusion criteria or alternative tool names, but the main use contexts are explicit.

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