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

Annotations already declare readOnlyHint=true, so the safety profile is covered and the bar is lower. The description adds that it maps to the Swell REST endpoint GET /subscriptions, but says nothing about pagination defaults, result ordering behavior, or rate limits beyond what the schema already documents.

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 short sentences with the capability summary front-loaded before the API endpoint detail. Slightly redundant with the title, but nothing wasted and no padding.

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 five-parameter list tool with no output schema and only a readOnly annotation, the description omits any indication of return shape, pagination semantics, or what a filtered result looks like. The fully documented schema carries most of the load, but the description is thin for a query endpoint.

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 every parameter (page, sort, limit, where, expand) is already documented with examples in the schema. The description's mention of 'filtering, sorting, and expansion' merely echoes the schema rather than adding syntax or format detail, so the baseline 3 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 states a specific verb and resource ('List subscriptions') and adds the three capabilities (filtering, sorting, expansion), so the agent knows exactly what the tool returns. It does not explicitly contrast itself with the sibling swell_get_subscription, though the list/get distinction is inferable from the name.

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?

Usage is only implied: the mention of filtering, sorting, and expansion signals that this is the collection-level query endpoint, but there is no explicit when-to-use statement and no named alternative (e.g. swell_get_subscription for a single record). Adequate but leaves routing to inference.

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