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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered elsewhere. The description contributes only pagination behavior (default 50, max 100), and says nothing about ordering, whether an empty list is possible, or how pagination should terminate — though the output schema covers the return shape.

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-line purpose followed by a compact Args block; the purpose sentence is front-loaded and there is no filler. The Args repetition of defaults already present in the schema costs a little, but the block stays short.

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?

The tool is simple and an output schema exists, so return values need not be described. Still, for a paginated list tool the description never explains paging strategy or whether a page smaller than limit signals the end, which is the main thing an agent needs to call it repeatedly and correctly.

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 33%, so the description carries real weight: it documents offset and limit and adds a 'max 100' constraint that the schema does not express. However, it ignores strategy_id entirely, which is the only parameter with a schema description and the most semantically ambiguous one available.

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 ('List the authenticated user's portfolios') and the ownership scope is explicit, which separates it from generic portfolio data tools like get_portfolio_statistics. It does not explicitly contrast with siblings such as list_watchlists or list_strategies, but the resource noun is unambiguous enough that an agent can select it.

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 or when-not-to-use guidance is given, and no alternative is named even though the sibling set contains list_watchlists, list_screeners, list_strategies and get_positions. The agent must infer that this tool is the portfolio enumeration path purely from the name.

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