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

With readOnlyHint=true already declaring the safe read profile, the description still adds value by disclosing what the payload contains (pricing, duration, credits, usage limits, trial and intro-offer flags) and by revealing the session/appointment compatibility filter behavior. It omits pagination/return-shape specifics but nothing contradicts 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?

Two tight sentences that front-load the resource and the returned fields before the optional filter, with no filler. The trailing REST endpoint reference is minor low-value clutter but does not hurt readability.

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?

There is no output schema, so the description usefully enumerates the returned plan attributes, partially compensating for that gap, and it covers the optional narrowing filters. For an 8-parameter read-only list tool it is largely complete, missing only pagination/response-format notes.

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 all eight parameters including the enum options and defaults. The description only reinforces the session/appointment compatibility filters, which is baseline-level added value rather than new syntax or semantics.

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?

Specific verb (List) plus resource (membership plans the studio sells) and it enumerates the plan subtypes and the fields surfaced (pricing, duration, credits, usage limits, trial/intro flags). This lets an agent distinguish it from momence_list_member_memberships (a member's owned plans) without opening a schema, though it never names that sibling explicitly.

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 states one conditional use case – optionally narrowing to plans usable for a given session or appointment – which maps to the compatibility filters. However there is no explicit when-not guidance or named alternative for retrieving a member's existing memberships versus the studio's catalog.

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