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

The description explicitly discloses read-only behavior (consistent with readOnlyHint annotation), requires OAuth read:portfolios, and warns that partial provider holdings make duplicate exposure a lower bound. This goes beyond the annotation by adding a reliability limitation and auth requirement.

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?

Three sentences with no filler; purpose is front-loaded, and each sentence adds behavioral or technical context. Efficient and well-structured.

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 well-covered: purpose, inputs (implicitly), required auth, read-only status, and a key limitation are all disclosed. The presence of an output schema means return values don't need description. No significant gaps remain for a read-only analysis 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 only 40% (portfolioId and candidateTicker have descriptions), while days, candidateWeightPct, and includeLookThrough lack explicit semantics. The description broadly references price-history and look-through but doesn't map these to parameters or explain units/meaning of candidateWeightPct or days.

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 clearly states the tool analyzes an ETF candidate against a user's portfolio, combining price-history fit metrics (correlation, beta, pro-forma volatility) with holdings look-through for duplicate exposure. This distinguishes it from sibling tools like analyze_etf_overlap and get_portfolio_analytics.

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 implies use when evaluating a candidate ETF for a specific portfolio, mentioning the look-through and coverage limitations. It names the required OAuth scope and read-only nature, providing clear context, though it doesn't explicitly contrast with alternatives like analyze_etf_overlap.

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