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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so safety is covered. The description adds genuinely new behavioral context — the 15-minute background refresh cadence — but says nothing about latency, whether the refresh is synchronous, or how the call behaves if the brokerage connection is stale or broken.

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?

One sentence, front-loaded with the verb and the resources fetched. The trailing parenthetical is slightly awkwardly phrased ('when asked about'), but it carries real information and no sentence 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?

For a zero-parameter read tool with full annotation coverage and no output schema, the description supplies the purpose and the refresh cadence an agent needs to decide whether to call it. Missing only a note on latency or failure modes for an unmounted brokerage.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate. Baseline 4 applies since no parameter semantics are needed.

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?

States a specific verb and resource: pulls latest holdings, balances and transactions from brokerages on demand. It is distinguishable from cache-reading siblings like my_portfolio or my_transactions, though it never names them explicitly to sharpen the boundary.

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?

The parenthetical 'they also refresh on their own every 15 minutes' implies this call is for when a fresh read is required immediately, which is implicit guidance on when it is unnecessary. However, there is no explicit 'use this when X, use my_portfolio instead when Y' routing.

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