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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered structurally. The description adds that these are previews and confirmation links (i.e., non-mutating informational output) plus the self-describing "help" affordance, but says nothing about auth requirements, rate limits, or what the link actions actually return.

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 "help" hint is well placed and useful, but the nine action names are recited verbatim from the enum, which is redundant bulk in an otherwise short description. Front-loading is weak because the lead sentence is a fragment that lists outputs before stating the tool's role.

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 two-parameter dispatcher with an opaque additionalProperties object and no output schema, deferring field discovery to action "help" is a defensible strategy, and the annotations cover safety. Still missing is any indication of what the preview/link actions return or how the nested params differ per action, leaving the agent dependent on a second round trip.

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 50% (the params object is documented, the action enum is not), and the description's enumeration of the nine action values merely duplicates the enum already present in the schema, adding no semantic detail. Its only genuine contribution is pointing at action "help" for the opaque nested params object, so it neither compensates for nor worsens the coverage gap.

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 identifies this as a read-only preview surface for plan/term/Premium upgrade changes, cancellation questions, and confirmation links, which separates it from the write-side manage_membership sibling. However the opening is a sentence fragment that lists returned artifacts rather than stating a clear verb+resource, so the purpose is inferred rather than declared.

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 tells the agent to call with action "help" to discover each action's fields, which is a usable invocation guideline, but it never states when to use get_membership versus manage_membership or when a preview should precede an actual change. Usage is only implied by the read-only framing.

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