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

Annotations already declare readOnlyHint=true, so the description doesn't need to reiterate safety. However, it adds critical behavioral context: the response always returns a complete holdings list with matched/unmatched flags, a coverage summary, and warns against presenting matched-only figures as the whole portfolio. This is valuable beyond the annotation.

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 description is somewhat long but well-structured: usage guidance first, followed by response structure details, caveats, and alternative tool reference. Every sentence adds value, though it could be slightly tighter without losing clarity.

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?

Given no output schema, the description fully explains the return shape (summary, holdings, insights, coverage banner). It also covers privacyMode and clarifies that holdings may lack weight/sector/insight for unmatched items. This is exceptionally complete for a non-trivial tool.

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% (each parameter has a description). The description adds value by explaining portfolioId's origin ('from list_portfolios'), clarifying days as a look-back window, and illustrating privacyMode's effect on output format. This enriches the schema's baseline.

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 starts with explicit use cases ('Use when the user asks to look at, review, or analyze THEIR portfolio / holdings / positions') and provides concrete example queries. It clearly distinguishes the tool from siblings like get_portfolio_analytics by naming that alternative for risk/diversification analysis.

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 description explicitly states when to use (portfolio review/analysis), when not to use for risk analytics (points to get_portfolio_analytics), and instructs to call list_portfolios first if portfolio ID is unknown. This provides clear decision guidance.

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