List my portfolios

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

Goes well beyond the readOnly/non-destructive annotations by disclosing the OAuth requirement and read:portfolios scope, that only the authenticated user's own data is returned, and the privacyMode default ('full' returns absolute $ vs 'weights_only' strips cash/value/cost basis). These are material behavioral facts an agent cannot infer from structured fields.

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?

Front-loaded with the 'Use when...' trigger and concrete user phrasings, then routing, then auth/privacy caveats. Each sentence serves a purpose, though the long list of example utterances and the return-field enumeration make it denser than strictly necessary.

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 compensates by enumerating the returned fields and noting position counts and computed summaries. Combined with the routing guidance, auth requirements, and default privacy behavior, an agent has everything needed to invoke it correctly and interpret the result.

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 already 100% for the single privacyMode parameter, but the description adds practical meaning: that the default is 'full' and what 'weights_only' actually hides versus preserves. It does not add example values or caveats beyond that, so it is a modest improvement over the schema rather than a full substitute.

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 ('Lists') and resource ('signed-in Bullrun user's virtual portfolios') and enumerates the computed fields returned (value, day change, cost basis, return, position counts). It is clearly distinguished from siblings like get_portfolio_context and get_portfolio_analytics by positioning itself as the entry point that yields a portfolioId for those tools.

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?

Explicitly names the triggering situations with concrete example utterances ('my portfolios', 'how are my investments doing'), and gives a routing rule: use this first when no specific portfolio is named, then pass the resulting portfolioId to the context/analytics tools. Alternatives and the condition selecting them are both stated.

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