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

No annotations, so the description carries the full behavioral burden. "Return" hints at a read, but the name suggests starting a transaction, and the description says nothing about side effects, whether a purchase is actually initiated, permissions, or what happens after selection.

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 compact sentence with the options front-loaded and no filler. The phrasing "speak first" is slightly informal but maps cleanly to the enum.

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?

No output schema and no annotations, and with a name/verb mismatch the agent cannot tell whether this initiates a purchase or returns informational options. That unresolved ambiguity is a significant completeness gap for a tool whose output shape is undeclared.

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 0%, so the description must compensate. It does map the three enum values to human terms (card, invoice, speak first vs. book_first), which helps, but it never names the parameter, explains the default of "card", or says what differing values change.

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?

"Return approved ways to purchase the Diagnostic" gives a verb+resource, and the three options (card, invoice, speak first) mirror the enum. But the tool name "start_diagnostic_purchase" implies initiating a purchase while the description's verb "Return" implies merely listing options; this tension leaves the core action ambiguous.

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?

No when-to-use guidance, prerequisites, or routing to alternatives. With siblings like get_diagnostic_details and book_executive_call in scope, an agent gets no signal on when this tool is the right choice versus those.

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