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

Annotations already establish that this is a read-only, closed-world lookup, so the lower bar applies. The description does add useful behavioral context beyond them — that results carry a verification date, a T-bill benchmark, and procedural guidance — but says nothing about response format, coverage of unsupported brokers, or how the 'date verified' freshness varies.

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 return contents are front-loaded and useful, but the trailing list of twelve broker names consumes roughly half the description without helping an agent call a free-text broker lookup; that space would be better spent on usage or format guidance.

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 one-parameter read tool with annotations covering the safety profile, the description is adequate: it conveys what comes back in lieu of an output schema. However, the unfulfilled 'by account type' promise and the absence of any fallback behavior for unknown brokers leave small but real gaps.

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 100% and the single broker parameter is documented with naming examples, so the baseline is 3. The description's claim that results are broken out 'by account type' implies a dimension that the schema exposes no parameter for, which adds confusion rather than meaning about the one input.

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 a specific resource (brokerage default cash / sweep rate) and enumerates what is returned: rate, account type, date verified, Treasury bill comparison, and move-cash steps. It is clearly not the same as get_treasury_yields or compare_after_tax, though it never explicitly contrasts itself with those siblings.

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 guidance, no conditions for choosing this over get_cash_rates or compare_after_tax, and no stated prerequisites (e.g., that the broker must be a supported name). Usage is only inferable from the subject matter.

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