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

Annotations already fully declare the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description only needs to add context. It adds the tenant-ownership constraint but leaves the term "session preview" undefined and says nothing about ordering, default result count, or pagination behavior.

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?

A single front-loaded sentence with no filler, which is appropriately compact for a list tool. It is arguably too terse rather than verbose, but no wording is wasted.

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?

With no output schema, the description should explain what a "session preview" actually contains (start time, recurrence, status?), and it does not. Combined with the unexplained limit parameter and no ordering semantics, an agent can invoke the tool but cannot predict or interpret results.

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 0%, so the description must carry the burden. It clarifies that webinarId targets a tenant-owned webinar, but the limit parameter (default 10, max 20) is never mentioned, leaving one of two parameters undocumented in both schema and description.

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 opens with a specific verb ("List") and a specific resource ("upcoming session previews"), scoped to a single tenant-owned webinar, so an agent knows exactly what it returns. It does not explicitly distinguish itself from siblings such as webinarstack.webinars.list or webinarstack.webinars.summary, which keeps it from 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?

There is no explicit when-to-use or when-not-to-use guidance and no named alternative for retrieving schedule data versus plain webinar metadata. At best the phrase "for one tenant-owned WebinarStack webinar" implies a precondition (the webinar must belong to the caller's tenant), but nothing tells the agent what to do otherwise.

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