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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds useful content scope — it discloses that the response includes the money-back promise, contact paths, and links to main site pages, which goes beyond the annotations and tells the agent what payload to expect.

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 sentences, both dense with content and zero filler. The content inventory comes first and the routing instruction ("Start here...") is front-loaded at the end where it is most actionable.

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 carries the burden of describing what comes back, and it does so concretely (overview text, promise details, contact, page links). For a zero-parameter informational tool with full annotation coverage, nothing an agent needs in order to call it correctly is missing.

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?

There are zero parameters and the schema is fully specified, so the baseline of 4 applies. Nothing in the description conflicts with or needs to compensate for the empty input schema.

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 names the specific resource (UBM itself) and enumerates the exact contents: what it is, who it's for, how it works, the money-back promise, contact info, and links to main pages. This clearly separates it from transactional siblings like ubm_quote_plan or ubm_start_signup, which handle pricing and signup rather than orientation.

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?

"Start here when someone asks what UBM is or does" gives an explicit entry condition and routing trigger. It stops short of naming when to hand off to a specific sibling (e.g., pricing questions to ubm_list_packages), so it is clear context without full exclusions.

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