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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the read-only, safe, closed-world profile is covered without the description. The description confirms this is a query-only tool but adds no behavioral context beyond what annotations and the schema already convey (no rate limits, no return-shape caveats), which is the expected lower bar when annotations carry the safety load.

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 terse sentences, front-loaded with the overall purpose and immediately followed by the action breakdown. Every clause earns its place with no filler or repetition.

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 multi-action read tool whose params are fully documented by the schema and whose safety profile is carried by annotations, the description names both actions and their scope adequately. No output schema exists, but the return values are simple query results, so little is missing; a note on pagination defaults or filters syntax would have pushed it higher.

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 description coverage is 100%, so the schema already documents page, sort, limit, filters, and subscription_id in detail. The description adds no parameter-level detail (no format, constraint, or interaction notes) beyond the schema, so the baseline 3 for high coverage applies.

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 gives a specific verb+resource (query subscriptions) and enumerates the two actions with their distinct behaviors (list = filtered/paginated query, show = single by ID). It is clear and self-contained, but it does not differentiate itself from any sibling (e.g., other read tools), which is what would be needed for 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 action descriptions imply when each mode applies (list for many, show for one by ID), but there is no explicit when-to-use guidance, no mention of alternatives, and no exclusivity/condition statements. Usage is inferable only from the action split, so it lands at the minimum-viable implied level.

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